ADAS1000-2BCPZ [ADI]
Low Power, Five Electrode Electrocardiogram (ECG) Analog Front End;
| 型号： | ADAS1000-2BCPZ |
| 厂家： | 
ADI |
| 描述： | Low Power, Five Electrode Electrocardiogram (ECG) Analog Front End |
| 文件： | 总80页 (文件大小：1673K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Low Power, Five Electrode
Electrocardiogram (ECG) Analog Front End
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
The ADAS1000 is a full-featured, 5-channel ECG including
respiration and pace detection, while the ADAS1000-1 offers
only ECG channels with no respiration or pace features. Similarly,
FEATURES
Biopotential signals in; digitized signals out
5 acquisition (ECG) channels and one driven lead
Parallel ICs for up to 10+ electrode measurements
Master ADAS1000 or ADAS1000-1 used with slave
ADAS1000-2
the ADAS1000-2 is a subset of the main device and is configured
for gang purposes with only the ECG channels enabled (no
respiration, pace, or right leg drive).
AC and dc lead-off detection
Internal pace detection algorithm on 3 leads
Support for user’s own pace
Thoracic impedance measurement (internal/external path)
Selectable reference lead
Scalable noise vs. power control, power-down modes
Low power operation from
The ADAS1000/ADAS1000-1/ADAS1000-2 are designed to
simplify the task of acquiring and ensuring quality ECG signals.
They provide a low power, small data acquisition system for
biopotential applications. Auxiliary features that aid in better
quality ECG signal acquisition include multichannel averaged
driven lead, selectable reference drive, fast overload recovery,
flexible respiration circuitry returning magnitude and phase
information, internal pace detection algorithm operating on
three leads, and the option of ac or dc lead-off detection. Several
digital output options ensure flexibility when monitoring and
analyzing signals. Value-added cardiac post processing is
executed externally on a DSP, microprocessor, or FPGA.
11 mW (1 lead), 15 mW (3 leads), 21 mW (all electrodes)
Lead or electrode data available
Supports AAMI EC11:1991/(R)2001/(R)2007, AAMI EC38
R2007, EC13:2002/(R)2007, IEC60601-1 ed. 3.0 b:2005,
IEC60601-2-25 ed. 2.0 :2011, IEC60601-2-27 ed. 2.0
b:2005, IEC60601-2-51 ed. 1.0 b: 2005
Fast overload recovery
Because ECG systems span different applications, the
ADAS1000/ADAS1000-1/ADAS1000-2 feature a power/noise
scaling architecture where the noise can be reduced at the
expense of increasing power consumption. Signal acquisition
channels can be shut down to save power. Data rates can be
reduced to save power.
Low or high speed data output rates
Serial interface SPI-/QSPI™-/DSP-compatible
56-lead LFCSP package (9 mm × 9 mm)
64-lead LQFP package (10 mm × 10 mm body size)
APPLICATIONS
ECG: monitor and diagnostic
Bedside patient monitoring, portable telemetry, Holter,
AED, cardiac defibrillators, ambulatory monitors, pace
maker programmer, patient transport, stress testing
To ease manufacturing tests and development as well as offer
holistic power-up testing, the ADAS1000/ADAS1000-1/
ADAS1000-2 offer a suite of features, such as dc and ac test
excitation via the calibration DAC and cyclic redundancy check
(CRC) redundancy testing, in addition to readback of all
relevant register address space.
GENERAL DESCRIPTION
The input structure is a differential amplifier input, thereby
allowing users a variety of configuration options to best suit
their application.
The ADAS1000/ADAS1000-1/ADAS1000-2 measure electro
cardiac (ECG) signals, thoracic impedance, pacing artifacts,
and lead-on/lead-off status and output this information in the
form of a data frame supplying either lead/vector or electrode
data at programmable data rates. Its low power and small size
make it suitable for portable, battery-powered applications.
The high performance also makes it suitable for higher end
diagnostic machines.
The ADAS1000/ADAS1000-1/ADAS1000-2 are available in two
package options, a 56-lead LFCSP package and a 64-lead LQFP
package. Both packages are specified over a −40°C to +85°C
temperature range.
Rev. B
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Technical Support
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ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Pacing Artifact Detection Function (ADAS1000 Only) ....... 42
Biventricular Pacers ................................................................... 45
Pace Detection Measurements ................................................. 45
Evaluating Pace Detection Performance................................. 45
Pace Width .................................................................................. 45
Pace Latency................................................................................ 45
Applications....................................................................................... 1
General Description......................................................................... 1
Revision History ............................................................................... 3
Functional Block Diagram .............................................................. 4
Specifications..................................................................................... 5
Noise Performance ....................................................................... 9
Timing Characteristics .............................................................. 10
Absolute Maximum Ratings.......................................................... 13
Thermal Resistance .................................................................... 13
ESD Caution................................................................................ 13
Pin Configurations and Function Descriptions ......................... 14
Typical Performance Characteristics ........................................... 18
Applications Information .............................................................. 25
Overview...................................................................................... 25
ECG Inputs—Electrodes/Leads................................................ 28
ECG Channel .............................................................................. 29
Electrode/Lead Formation and Input Stage Configuration.. 30
Defibrillator Protection ............................................................. 34
ESIS Filtering............................................................................... 34
ECG Path Input Multiplexing................................................... 34
Common-Mode Selection and Averaging .............................. 35
Wilson Central Terminal (WCT)............................................. 36
Right Leg Drive/Reference Drive ............................................. 36
Calibration DAC......................................................................... 37
Gain Calibration......................................................................... 37
Lead-Off Detection .................................................................... 37
Shield Driver ............................................................................... 38
Respiration (ADAS1000 Model Only)..................................... 38
Evaluating Respiration Performance ....................................... 41
Extend Switch On Respiration Paths ....................................... 41
Pace Detection via Secondary Serial Interface (ADAS1000
and ADAS1000-1 Only) ............................................................ 45
Filtering ....................................................................................... 46
Voltage Reference....................................................................... 47
Gang Mode Operation............................................................... 47
Interfacing in Gang Mode......................................................... 49
Serial Interfaces............................................................................... 50
Standard Serial Interface ........................................................... 50
Secondary Serial Interface......................................................... 54
RESET
.......................................................................................... 54
Function................................................................................ 54
PD
SPI Output Frame Structure (ECG and Status Data) ................ 55
SPI Register Definitions and Memory Map................................ 56
Control Registers Details............................................................... 57
Examples of Interfacing to the ADAS1000 ............................. 74
Software Flowchart .................................................................... 77
Power Supply, Grounding, and Decoupling Strategy............ 78
AVDD .......................................................................................... 78
ADCVDD and DVDD Supplies............................................... 78
Unused Pins/Paths ..................................................................... 78
Layout Recommendations ........................................................ 78
Outline Dimensions....................................................................... 79
Ordering Guide .......................................................................... 80
Rev. B | Page 2 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
REVISION HISTORY
6/14—Rev. A to Rev. B
1/13—Rev. 0 to Rev. A
Moved Revision History...................................................................3
Change to AC Lead-Off, Frequency Range Parameter, Table 2..7
Changes to Figure 17 ......................................................................18
Changes to Figure 40 and Figure 41 .............................................22
Changes to ECG Channel Section ................................................29
Replaced Figure 57..........................................................................30
Added Figure 58, Figure 59, Figure 60, Figure 61, and Figure 62;
Renumbered Sequentially ..............................................................31
Deleted Figure 63, Figure 64, and Figure 65; Renumbered
Sequentially......................................................................................35
Change to Figure 65, Figure 66, and Figure 67 ...........................35
Changes to Lead-Off Detection Section, Added Figure 68;
Renumbered Sequentially ..............................................................37
Changes to Respiration (ADAS1000 Model Only) Section and
Figure 69, Figure 70, and Figure 71; Added Table 13 and
Table 14; Renumbered Sequentially..............................................39
Changes to Pacing Artifact Detection Function (ADAS1000
Only) Section ...................................................................................42
Changes to Evaluating Pace Detection Performance Section ...45
Added Pace Width Section ............................................................45
Changes to Standard Serial Interface Section..............................50
Changes to Features Section............................................................1
Changes to Table 1 ............................................................................3
Changes to Excitation Current, Test Conditions/Comments,
Table 2.................................................................................................5
Added Table 3; Renumbered Sequentially.....................................9
Changes to Respiration (ADAS1000 Model Only) Section,
Figure 66, and Internal Respiration Capacitors Section ............37
Changes to Figure 67 ......................................................................38
Changes to Figure 68 ......................................................................39
Added Evaluating Pace Detection Performance Section...........43
Added Table 15................................................................................47
Changes to Clocks Section.............................................................51
Changes to RESPAMP Name, Function, Table 28......................57
Changes to Bits[14:9], Function, Table 30 ...................................59
Changes to Ordering Guide...........................................................78
8/12—Revision 0: Initial Version
DRDY
Changes to Data Ready (
) Section.....................................52
Changes to Secondary Serial Interface Section and Table 25....54
Change to Bit 3, Table 28................................................................57
Changes to Table 43 ........................................................................67
Change to Table 45..........................................................................68
Changes to Table 50 ........................................................................70
Changes to Table 52 ........................................................................71
Changes to Table 53 ........................................................................72
Rev. B | Page 3 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
FUNCTIONAL BLOCK DIAGRAM
REFIN REFOUT CAL_DAC_IO RLD_SJ
RLD_OUT CM_IN
CM_OUT/WCT
SHIELD
AVDD
IOVDD
DRIVEN
LEAD
AMP
–
SHIELD
DRIVE
AMP
VREF
ADCVDD
ADCVDD, DVDD
1.8V
REGULATORS
DVDD
CALIBRATION
DAC
+
VCM_REF
(1.3V)
RESPIRATION
DAC
COMMON-
MODE AMP
AC
LEAD-OFF
DAC
AC
LEAD-OFF
DETECTION
10kΩ
BUFFER
PACE
DETECTION
CS
MUXES
SCLK
5× ECG PATH
AMP
ELECTRODES
×5
SDI
FILTERS,
CONTROL,
AND
INTERFACE
LOGIC
ADC
SDO
DRDY
GPIO0/MCS
GPIO1/MSCLK
GPIO2/MSDO
GPIO3
EXT_RESP_LA
EXT_RESP_LL
ADC
AMP
EXT_RESP_RA
CLOCK GEN/OSC/
EXTERNAL CLK
SOURCE
CLK_IO
RESPIRATION PATH
ADAS1000
XTAL1
XTAL2
Figure 1. ADAS1000 Full Featured Model
Table 1. Overview of Features Available from ADAS1000 Generics
Pace
Detection
Shield
Driver
Master
Package
Option
Generic1
ECG
Operation
Master/slave
Master/slave
Slave
Right Leg Drive
Respiration
Interface2
Yes
ADAS1000
5 ECG channels
5 ECG channels
5 ECG channels
3 ECG channels
3 ECG channels
Yes
Yes
Yes
Yes
Yes
LFCSP, LQFP
LFCSP
ADAS1000-1
ADAS1000-2
ADAS1000-3
ADAS1000-4
Yes
Yes
LFCSP, LQFP
LFCSP, LQFP
LFCSP, LQFP
Master/slave
Master/slave
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
1 The ADAS1000-2 is a companion device for increased channel count purposes. It has a subset of features and is not intended for standalone use. It can be used in
conjunction with any master device.
2 Master interface is provided for users wishing to utilize their own digital pace algorithm; see the Secondary Serial Interface section.
Rev. B | Page 4 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
SPECIFICATIONS
AVDD = 3.3 V 5%, IOVDD = 1.65 V to 3.6 V, AGND = DGND = 0 V, REFIN tied to REFOUT, externally supplied crystal/clock =
8.192 MHz. Decoupling for reference and supplies as noted in the Power Supply, Grounding, and Decoupling Strategy section. TA =
−40°C to +85°C, unless otherwise noted. Typical specifications are mean values at TA = 25°C.
For specified performance, internal ADCVDD and DVDD linear regulators have been used. They may be supplied from external
regulators. ADCVDD = 1.8 V 5%, DVDD = 1.8 V 5%.
Front-end gain settings: GAIN 0 = ×1.4, GAIN 1 = ×2.1, GAIN 2 = ×2.8, GAIN 3 = ×4.2.
Table 2.
Parameter
Min
Typ
Max
Unit
Test Conditions/Comments
ECG CHANNEL
These specifications apply to the following pins:
ECG1_LA, ECG2_LL, ECG3_RA, ECG4_V1, ECG5_V2,
CM_IN (CE mode), EXT_RESP_xx pins when used in
extend switch mode
Electrode Input Range
Independent of supply
GAIN 0 (gain setting ×1.4)
GAIN 1 (gain setting ×2.1)
GAIN 2 (gain setting ×2.8)
GAIN 3 (gain setting ×4.2)
0.3
1.3
1.3
1.3
1.3
1
2.3
V
0.63
0.8
1.97
1.8
V
V
0.97
−40
1.63
+40
V
Input Bias Current
Input Offset
nA
Relates to each electrode input; over operating range;
dc and ac lead-off are disabled
−200
+200
nA
AGND to AVDD
−7
mV
Electrode/vector mode with VCM = VCM_REF GAIN 3
−7
mV
GAIN 2
GAIN 1
GAIN 0
−15
−22
2
mV
mV
Input Offset Tempco1
μV/°C
GΩ||pF
Input Amplifier Input
1||10
At 10 Hz
Impedance2
CMRR2
105
110
dB
51 kΩ imbalance, 60 Hz with 300 mV differential dc
offset; per AAMI/IEC standards; with driven leg loop closed
Crosstalk1
Resolution2
80
19
18
16
dB
Between channels
Bits
Bits
Bits
Electrode/vector mode, 2 kHz data rate, 24-bit data-word
Electrode/vector mode, 16 kHz data rate, 24-bit data-word
Electrode/analog lead mode, 128 kHz data rate, 16-bit
data-word
Integral Nonlinearity Error
Differential Nonlinearity Error
Gain2
30
5
ppm
ppm
GAIN 0; all data rates
GAIN 0
Referred to input. (2 × VREF)/Gain/(2N − 1); applies after
factory calibration; user calibration adjusts this number
GAIN 0 (×1.4)
GAIN 1 (×2.1)
GAIN 2 (×2.8)
GAIN 3 (×4.2)
4.9
µV/LSB
μV/LSB
μV/LSB
μV/LSB
μV/LSB
μV/LSB
μV/LSB
μV/LSB
μV/LSB
μV/LSB
At 19-bit level in 2 kHz data rate
At 18-bit level in 16 kHz data rate
At 16-bit level in 128 kHz data rate
At 19-bit level in 2 kHz data rate
At 18-bit level in 16 kHz data rate
At 16-bit level in 128 kHz data rate
At 19-bit level in 2 kHz data rate
At 18-bit level in 16 kHz data rate
At 16-bit level in 128 kHz data rate
9.81
39.24
3.27
6.54
26.15
2.45
4.9
19.62
1.63
No factory calibration for this gain setting
At 19-bit level in 2 kHz data rate
3.27
μV/LSB
μV/LSB
%
At 18-bit level in 16 kHz data rate
At 16-bit level in 128 kHz data rate
13.08
+0.01
Gain Error
−1
−2
+1
+2
GAIN 0 to GAIN 2, factory calibrated; programmable
user or factory calibration option enables; factory gain
calibration applies only to standard ECG interface
+0.1
%
GAIN 3 setting, no factory calibration for this gain
Rev. B | Page 5 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Parameter
Min
−0.1
−0.5
Typ
+0.02
+0.1
25
Max
+0.1
+0.5
Unit
%
Test Conditions/Comments
GAIN 0 to GAIN 2
GAIN 3
Gain Matching
%
Gain Tempco1
Input Referred Noise1
ppm/°C
GAIN 2, 2 kHz data rate, see Table 4
Analog Lead Mode
6
μV p-p
μV p-p
μV p-p
μV p-p
μV p-p
μV p-p
μV p-p
dB
0.5 Hz to 40 Hz; high performance mode
0.05 Hz to 150 Hz; high performance mode
0.05 Hz to 150 Hz; low power mode
0.05 Hz to 150 Hz; high performance mode
0.05 Hz to 150 Hz; low power mode
0.05 Hz to 150 Hz; high performance mode
0.05 Hz to 150 Hz; low power mode
At 120 Hz
10
12
11
12
14
16
100
65
104
100
Electrode Mode
Digital Lead Mode
Power Supply Sensitivity2
Analog Channel Bandwidth1
Dynamic Range1
Signal-to-Noise Ratio1
COMMON-MODE INPUT
Input Voltage Range
Input Impedance2
kHz
dB
GAIN 0, 2 kHz data rate, −0.5 dBFS input signal, 10 Hz
−0.5 dB FS input signal
dB
CM_IN pin
0.3
2.3
V
1||10
1
GΩ||pF
nA
Input Bias Current
−40
+40
Over operating range; dc and ac lead-off disabled
AGND to AVDD
−200
+200
nA
COMMON-MODE OUTPUT
VCM_REF
CM_OUT pin
1.28
0.3
1.3
1.3
0.75
4
1.32
2.3
V
Internal voltage; independent of supply
No dc load
Output Voltage, VCM
Output Impedance1
Short Circuit Current1
V
kΩ
mA
%
Not intended to drive current
Electrode Summation
Weighting Error2
1
Resistor matching error
RESPIRATION FUNCTION
(ADAS1000 ONLY)
These specifications apply to the following pins:
EXT_RESP_LA, EXT_RESP_LL, EXT_RESP_RA and selected
internal respiration paths (Lead I, Lead II, Lead III)
Input Voltage Range
0.3
2.3
V
AC-coupled, independent of supply
Programmable gain (10 states)
Input Voltage Range (Linear
Operation)
1.8/gain
V p-p
Input Bias Current
Input Referred Noise1
Frequency2
−10
1
+10
nA
Applies to EXT_RESP_xx pins over AGND to AVDD
0.85
μV rms
kHz
46.5 to 64
Programmable frequency, see Table 30
Excitation Current
Respiration drive current corresponding to differential
voltage programmed by RESPAMP bits in RESPCTL
register. Internal respiration mode, cable 5 kΩ/200 pF,
1.2 kΩ chest impedance
64
32
16
8
μA p-p
μA p-p
μA p-p
μA p-p
bits
Drive Range A
Drive Range B2
Drive Range C2
Drive Range D2
Update rate 125 Hz
Resolution2
Measurement Resolution1
24
0.2
Ω
Cable <5 kΩ/200 pF per electrode, body resistance
modeled as 1.2 kΩ
0.02
Ω
No cable impedance, body resistance modeled as 1.2 kΩ
Digitally programmable in steps of 1
In-Amp Gain1
Gain Error
1 to 10
1
%
LSB weight for GAIN 0 setting
Gain Tempco1
25
2
ppm/C
RIGHT LEG DRIVE/DRIVEN LEAD
(ADAS1000/ADAS1000-1 ONLY)
Output Voltage Range
0.2
−5
AVDD − 0.2
+5
V
RLD_OUT Short Circuit Current
mA
External protection resistor required to meet regulatory
patient current limits; output shorted to AVDD/AGND
Closed-Loop Gain Range2
Slew Rate2
Input Referred Noise1
Amplifier GBP2
25
V/V
200
8
mV/ms
μV p-p
MHz
0.05 Hz to 150 Hz
1.5
Rev. B | Page 6 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
Parameter
Min
Typ
Max
Unit
Test Conditions/Comments
DC LEAD-OFF
Internal current source, pulls up open ECG pins;
programmable in 10 nA steps: 10 nA to 70 nA
Lead-Off Current Accuracy
High Threshold Level1
10
%
V
Of programmed value
2.4
Inputs are compared to threshold levels; if inputs
exceed levels, lead-off flag is raised
Low Threshold Level1
Threshold Accuracy
AC LEAD-OFF
0.2
25
V
mV
Programmable in 4 steps: 12.5 nA rms, 25 nA rms,
50 nA rms, 100 nA rms
Frequency Range
Lead-Off Current Accuracy
REFIN
2.039
10
kHz
%
Fixed frequency
Of programmed value, measured into low impedance
Input Range2
1.76
450
1.8
1.84
950
V
Channel gain scales directly with REFIN
Per active ADC
Input Current
113
675
μA
μA
5 ECG channels and respiration enabled
REFOUT
On-chip reference voltage for ADC; not intended to
drive other components reference inputs directly,
must be buffered externally
Output Voltage, VREF
Reference Tempco1
Output Impedance2
Short Circuit Current1
Voltage Noise1
1.785
1.8
10
1.815
V
ppm/°C
Ω
0.1
4.5
33
mA
Short circuit to ground
μV p-p
μV p-p
0.05 Hz to 150 Hz (ECG band)
0.05 Hz to 5 Hz (respiration)
17
CALIBRATION DAC
Available on CAL_DAC_IO (output for master, input
for slave)
DAC Resolution
10
Bits
V
Full-Scale Output Voltage
Zero-Scale Output Voltage
DNL
2.64
0.24
−1
2.7
0.3
2.76
0.36
+1
No load, nominal FS output is 1.5 × REFOUT
No load
V
LSB
kΩ
Output Series Resistance2
10
5
Not intended to drive low impedance load, used for
slave CAL_DAC_IO configured as an input
Input Current
nA
When used as input
CALIBRATION DAC TEST TONE
Output Voltage
0.9
1
1.1
mV p-p
Hz
Rides on common-mode voltage, VCM_REF = 1.3 V
Square Wave
1
Low Frequency Sine Wave
High Frequency Sine Wave
10
150
Hz
Hz
SHIELD DRIVER (ADAS1000/
ADAS1000-1 ONLY)
Output Voltage Range
Gain
0.3
2.3
V
Rides on common-mode voltage, VCM
1
V/V
mV
μA
nF
Offset Voltage
−20
+20
25
Short Circuit Current
Stable Capacitive Load2
CRYSTAL OSCILLATOR
Frequency2
15
Output current limited by internal series resistance
Applied to XTAL1 and XTAL2
10
8.192
15
MHz
ms
Start-Up Time2
Internal startup
CLOCK_IO
External clock source supplied to CLK_IO; this pin
is configured as an input when the device is
programmed as a slave
Operating Frequency2
Input Duty Cycle2
Output Duty Cycle2
8.192
50
MHz
%
20
80
%
DIGITAL INPUTS
Applies to all digital inputs
Input Low Voltage, VIL
Input High Voltage, VIH
Input Current, IIH, IIL
0.3 × IOVDD
V
0.7 × IOVDD
V
−1
+1
μA
μA
pF
−20
+20
RESET
has an internal pull-up
Pin Capacitance2
3
Rev. B | Page 7 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Parameter
Min
Typ
Max
Unit
Test Conditions/Comments
DIGITAL OUTPUTS
Output Low Voltage, VOL
Output High Voltage, VOH
Output Rise/Fall Time
DVDD REGULATOR
Output Voltage
0.4
V
ISINK = 1 mA
IOVDD − 0.4
1.75
V
ISOURCE = −1 mA
4
ns
Capacitive load = 15 pF, 20% to 80%
Internal 1.8 V regulator for DVDD
1.8
1
1.85
1.85
V
Available Current1
mA
mA
Droop < 10 mV; for external device loading purposes
Short Circuit Current limit
ADCVDD REGULATOR
40
Internal 1.8 V regulator for ADCVDD; not
recommended as a supply for other circuitry
Output Voltage
Short Circuit Current Limit
POWER SUPPLY RANGES2
AVDD
1.75
1.8
40
V
mA
3.15
1.65
1.71
1.71
3.3
5.5
V
V
V
V
IOVDD
3.6
ADCVDD
1.8
1.8
1.89
1.89
If applied by external 1.8 V regulator
If applied by external 1.8 V regulator
DVDD
POWER SUPPLY CURRENTS
AVDD Standby Current
IOVDD Standby Current
785
1
975
60
μA
μA
EXTERNALLY SUPPLIED ADCVDD
AND DVDD
All 5 channels enabled, RLD enabled, pace enabled
AVDD Current
ADCVDD Current
DVDD Current
3.4
3.1
4.25
6.2
4.7
7
6.25
5.3
6.3
9
mA
mA
mA
mA
mA
mA
mA
mA
mA
High performance mode
Low performance mode
High performance mode, respiration enabled
High performance mode
6.5
9
Low performance mode
High performance mode, respiration enabled
High performance mode
2.7
1.4
3.4
5
3.5
5.5
Low performance mode
High performance mode, respiration enabled
All 5 channels enabled, RLD enabled, pace enabled
INTERNALLY SUPPLIED ADCVDD
AND DVDD
AVDD Current
12.5
9.4
15.3
12.4
17.3
mA
mA
mA
High performance mode
Low performance mode
14.8
High performance mode, respiration enabled
All 5 channels enabled, RLD enabled, pace enabled
POWER DISSIPATION
Externally Supplied ADCVDD
and DVDD3
All 5 Input Channels and RLD
27
21
mW
mW
High performance (low noise)
Low power mode
Internally Supplied ADCVDD
and DVDD
All 5 channels enabled, RLD enabled, pace enabled
All 5 Input Channels and RLD
41
31
mW
mW
High performance (low noise)
Low power mode
OTHER FUNCTIONS4
Power Dissipation
Respiration
7.6
mW
μW
Shield Driver
150
1 Guaranteed by characterization, not production tested.
2 Guaranteed by design, not production tested.
3 ADCVDD and DVDD can be powered from an internal LDO or, alternatively, can be powered from external 1.8 V rail, which may result in a lower power solution.
4 Pace is a digital function and incurs no power penalty.
Rev. B | Page 8 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
NOISE PERFORMANCE
Table 3. Typical Input Referred Noise over 0.5 Second Window (µV p-p)1
GAIN 0 (×1.4) GAIN 1 (×2.1) GAIN 2 (×2.8) GAIN 3 (×4.2)
1 VCM 0.67 VCM 0.5 VCM 0.3 VCM
Mode
Analog Lead Mode3
Data Rate2
High Performance Mode
2 kHz (0.5 Hz to 40 Hz)
2 kHz (0.05 Hz to 150 Hz)
8
14
6
11
5
9
4
7.5
1 Typical values measured at 25°C, not subject to production test.
2 Data gathered using the 2 kHz packet/frame rate is measured over 0.5 seconds. The ADAS1000 internal programmable low-pass filter is configured for either 40 Hz or
150 Hz bandwidth. The data is gathered and post processed using a digital filter of either 0.05 Hz or 0.5 Hz to provide data over noted frequency bands.
3 Analog lead mode as shown in Figure 58.
Table 4. Typical Input Referred Noise (μV p-p)1
GAIN 0 (×1.4) GAIN 1 (×2.1) GAIN 2 (×2.8) GAIN 3 (×4.2)
Mode
Data Rate2
1 VCM
0.67 VCM
0.5 VCM
0.3 VCM
Analog Lead Mode3
High Performance Mode
2 kHz (0.5 Hz to 40 Hz)
2 kHz (0.05 Hz to 150 Hz)
2 kHz (0.05 Hz to 250 Hz)
2 kHz (0.05 Hz to 450 Hz)
16 kHz
12
20
27
33.5
95
8.5
14.5
18
24
65
6
10
14.5
19
50
5
8.5
10.5
13.5
39
128 kHz
180
13
22
110
215
130
9.5
15.5
75
105
7.5
12
59
116
80
5.5
9
45
85
Low Power Mode
2 kHz (0.5 Hz to 40 Hz)
2 kHz (0.05 Hz to 150 Hz)
16 kHz
128 kHz
145
Electrode Mode4
High Performance Mode
2 kHz (0.5 Hz to 40 Hz)
2 kHz (0.05 Hz to 150 Hz)
2 kHz (0.05 Hz to 250 Hz)
2 kHz (0.05 Hz to 450 Hz)
16 kHz
13
21
26
34.5
100
190
14
22
110
218
9.5
15
19
25
70
139
9.5
15.5
75
8
11
5.5
9
11.5
14.5
41
15.5
20.5
57
110
7.5
12
128 kHz
85
Low Power Mode
2 kHz (0.5 Hz to 40 Hz)
2 kHz (0.05 Hz to 150 Hz)
16 kHz
5.5
9.5
45
60
120
128 kHz
145
88
Digital Lead Mode5, 6
High Performance Mode
2 kHz (0.5 Hz to 40 Hz)
2 kHz (0.05 Hz to 150 Hz)
2 kHz (0.05 Hz to 250 Hz)
2 kHz (0.05 Hz to 450 Hz)
16 kHz
2 kHz (0.5 Hz to 40 Hz)
2 kHz (0.05 Hz to 150 Hz)
16 kHz
16
25
34
46
130
18
30
11
19
23
31
90
12.5
21
9
6.5
10
13
17.5
50
7
15
18
24
70
10
16
80
Low Power Mode
11
58
145
100
1 Typical values measured at 25°C, not subject to production test.
2 Data gathered using the 2 kHz packet/frame rate is measured over 20 seconds. The ADAS1000 internal programmable low-pass filter is configured for either 40 Hz or
150 Hz bandwidth. The data is gathered and post processed using a digital filter of either 0.05 Hz or 0.5 Hz to provide data over noted frequency bands.
3 Analog lead mode as shown in Figure 58.
4 Single-ended input electrode mode as shown in Figure 61. Electrode mode refers to common electrode A, common electrode B, and single-ended input electrode
configurations. See Electrode/Lead Formation and Input Stage Configuration section.
5 Digital lead mode as shown in Figure 59.
6 Digital lead mode is available in 2 kHz and 16 kHz data rates.
Rev. B | Page 9 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
TIMING CHARACTERISTICS
Standard Serial Interface
AVDD = 3.3 V 5%, IOVDD = 1.65 V to 3.6 V, AGND = DGND = 0 V, REFIN tied to REFOUT, externally supplied crystal/clock =
8.192 MHz. TA = −40°C to +85°C, unless otherwise noted. Typical specifications are mean values at TA = 25°C.
Table 5.
IOVDD
2.5 V
Parameter1
Output Rate2
3.3 V
1.8 V
Unit
Description
2
128
kHz
Across specified IOVDD supply range; three programmable output data
rates available as configured in FRMCTL register (see Table 37) 2 kHz,
16 kHz, 128 kHz; use skip mode for slower rates
SCLK Cycle Time
25
8.5
3
40
9.5
3
50
12
3
ns min
ns min
ns min
ns min
ns min
ns typ
ns max
ns min
ns min
ns min
ns min
ns min
See Table 21 for details on SCLK vs. packet data rates
CS valid setup time to rising SCLK
CS valid hold time to rising SCLK
SCLK high time
tCSSA
tCSHA
tCH
tCL
tDO
8
8
8.5
11
2
8
8
11.5
19
2
8
8
20
24
2
SCLK low time
SCLK falling edge to SDO valid delay; SDO capacitance of 15 pF
tDS
tDH
tCSSD
tCSHD
tCSW
SDI valid setup time from SCLK rising edge
SDI valid hold time from SCLK rising edge
CS valid setup time from SCLK rising edge
CS valid hold time from SCLK rising edge
2
2
2
2
2
2
2
2
2
25
40
50
CS high time between writes (if used). Note that CS is an optional input,
it may be tied permanently low. See a full description in the Serial
Interfaces section.
2
tDRDY_CS
0
0
0
ns min
ns typ
ns min
DRDY to CS setup time
tCSO
6
7
9
Delay from CS assert to SDO active
Minimum pulse width; RESET is edge triggered
RESET Low Time2
20
20
20
1 Guaranteed by characterization, not production tested.
2 Guaranteed by design, not production tested.
SCLK
tCSSA
tCSHA
tCSSD
tCH tCL
tCSHD
CS
tCSW
tDS
tDH
MSB
LSB
DB[31]
DB[30]
DB[29]
DB[25]
DB[24]
DB[23]
DB[1]
DB[0]
SDI
R/W
ADDRESS
DATA
tCSO
LSB
MSB
DO_1LAST
DO_0LAST
DRDV
DO_31LAST
DO_30LAST
DO_29LAST
DO_25LAST
SDO
tDO
Figure 2. Data Read and Write Timing Diagram (CPHA = 1, CPOL = 1)
Rev. B | Page 10 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
tDRDY_CS
DRDY
SCLK
tCH
tCL
tCSSA
tCSSD
tCSHD
tCSHA
CS
tCSW
tDS
tDH
LSB
MSB
LSB
MSB
DB[1] DB[0]
N + 1
N + 1
DB[30]
N + 1
DB[31]
N
DB[30]
N
DB[29]
N
DB[25]
N
DB[24]
N
DB[31]
N + 1
SDI
DB[1]
DB[23]
DATA = NOP or 0x40
MSB
R/W
ADDRESS = 0x40 (FRAMES)
DATA
tCSO
MSB
LSB
LSB
DB[24]
N – 1
DB[31]
N – 1
DB[30]
N – 1
DB[25]
N – 1
DB[23]
N – 1
DB[1]
N – 1
DB[0]
N – 1
DB[31]
N
DB[30]
N
DB[1]
N
DB[0]
N
SDO
DRDY
tDO
PREVIOUS DATA
HEADER (FIRST WORD OF FRAME)
Figure 3. Starting Read Frame Data (CPHA = 1, CPOL = 1)
tCH
SCLK
tCSSD
t
tCL
CSSA
t
CSHA
tCSHD
CS
tCSW
tDH
tDS
LSB
DB[0]
MSB
DB[31]
DB[30]
DB[29]
DB[28]
DB[24]
DB[1]
DB[2]
SDI
R/W
ADDRESS
DATA
tDO
MSB
LSB
DO_0
DO_31LAST
DO_1
DO_30
DO_29
DO_28
LAST
SDO
LAST
LAST
LAST
LAST
tDO
Figure 4. Data Read and Write Timing Diagram (CPHA = 0, CPOL = 0)
Rev. B | Page 11 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Secondary Serial Interface (Master Interface for Customer-Based Digital Pace Algorithm) ADAS1000/ADAS1000-1 Only
AVDD = 3.3 V 5%, IOVDD = 1.65 V to 3.6 V, AGND = DGND = 0 V, REFIN tied to REFOUT, externally supplied crystal/clock =
8.192 MHz. TA = −40°C to +85°C, unless otherwise noted. Typical specifications are mean values at TA = 25°C. The following timing
specifications apply for the master interface when ECGCTL register is configured for high performance mode (ECGCTL[3] = 1), see
Table 28.
Table 6.
Parameter1
Min Typ
Max Unit Description
Output Frame Rate2
128
2.5 × crystal
kHz
All five 16-bit ECG data-words are available at frame rate of 128 kHz only
2
fSCLK
MHz Crystal frequency = 8.192 MHz
frequency
tMCSSA
tMDO
tMCSHD
tMCSW
24.4
ns
ns
ns
ns
MCS valid setup time
0
48.8
MSCLK rising edge to MSDO valid delay
MCS valid hold time from MSCLK falling edge
2173
MCS high time, SPIFW = 0, MCS asserted for entire frame as shown in
Figure 5, and configured in Table 33
2026
ns
MCS high time, SPIFW = 1, MCS asserted for each word in frame as shown in
Figure 6 and configured in Table 33
1 Guaranteed by characterization, not production tested.
2 Guaranteed by design, not production tested.
tMSCLK
2
tMSCLK
MSCLK
tMCSSA
tMCSHD
MCS
tMCSW
SPIFW = 0*
MSB
LSB
MSB
LSB
MSB
LSB
MSDO
D0_15
D5_0
D0_14
D0_1
tMDO
D0_0
D1_15
D1_14
D6_15
D6_14
D6_0
16-BIT CRC WORD
HEADER: 0xF AND 12-BIT COUNTER
5 × 16-BIT ECG DATA
*SPIFW = 0 PROVIDES MCS FOR EACH FRAME, SCLK STAYS HIGH FOR 1/2 MSCLK CYCLE BETWEEN EACH WORD.
Figure 5. Data Read and Write Timing Diagram for SPIFW = 0, Showing Entire Packet of Data (Header, 5 ECG Words, and CRC Word)
tMSCLK
MSCLK
tMCSSA
tMSCLK
tMCSHD
MCS
tMCSW
SPIFW = 1*
MSB
LSB
D0_0
MSB
D1_15
LSB
D5_0
MSB
LSB
MSDO
D0_15
D0_14
D0_1
tMDO
D1_14
D6_15
D6_14
D6_0
HEADER: 0xF AND 12-BIT COUNTER
5 × 16-BIT ECG DATA
16-BIT CRC WORD
*SPIFW = 1 PROVIDES MCS FOR EACH FRAME, SCLK STAYS HIGH FOR 1 MSCLK CYCLE BETWEEN EACH WORD.
Figure 6. Data Read and Write Timing Diagram for SPIFW = 1, Showing Entire Packet of Data (Header, 5 ECG Words, and CRC Word)
Rev. B | Page 12 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
ABSOLUTE MAXIMUM RATINGS
Table 7.
THERMAL RESISTANCE
θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.
Parameter
Rating
AVDD to AGND
−0.3 V to +6 V
Table 8. Thermal Resistance1
Package Type
56-Lead LFCSP
64-Lead LQFP
IOVDD to DGND
ADCVDD to AGND
DVDD to DGND
REFIN/REFOUT to REFGND
ECG and Analog Inputs to AGND
Digital Inputs to DGND
REFIN to ADCVDD
AGND to DGND
REFGND to AGND
−0.3 V to +6 V
−0.3 V to +2.5 V
−0.3 V to +2.5 V
−0.3 V to +2.1 V
−0.3 V to AVDD + 0.3 V
−0.3 V to IOVDD + 0.3 V
ADCVDD + 0.3 V
−0.3 V to + 0.3 V
−0.3 V to + 0.3 V
10 mA
θJA
35
42.5
Unit
°C/W
°C/W
1 Based on JEDEC standard 4-layer (2S2P) high effective thermal conductivity
test board (JESD51-7) and natural convection.
ESD CAUTION
ECG Input Continuous Current
Storage Temperature Range
−65°C to +125°C
Operating Junction Temperature Range −40°C to +85°C
Reflow Profile
Junction Temperature
J-STD 20 (JEDEC)
150°C max
ESD
HBM
FICDM
2500 V
1000 V
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Rev. B | Page 13 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
1
2
AGND
ECG5_V2
ECG4_V1
ECG3_RA
ECG2_LL
ECG1_LA
REFIN
REFOUT
REFGND
42
41
40
PIN 1
DGND
IOVDD
GPIO0/MCS
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
INDICATOR
3
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
1
2
NC
NC
4
39 GPIO1/MSCLK
PIN 1
AGND
DGND
IOVDD
SDO
5
38
37
36
35
34
33
32
31
30
29
GPIO2/MSDO
GPIO3
DGND
CS
DRDY
SDI
SCLK
SDO
IOVDD
DGND
ADAS1000
3
6
RESPDAC_RA
EXT_RESP_RA
56-LEAD LFCSP
7
4
8
TOP VIEW
(Not to Scale)
5
SCLK
EXT_RESP_LL
EXT_RESP_LA
REFGND
9
6
10
11
12
13
14
SDI
EXT_RESP_LA
EXT_RESP_LL
EXT_RESP_RA
RESPDAC_RA
AGND
7
DRDY
ADAS1000
64-LEAD LQFP
8
REFOUT
CS
9
TOP VIEW
(Not to Scale)
REFIN
DGND
GPIO3
GPIO2/MSDO
GPIO1/MSCLK
GPIO0/MCS
IOVDD
DGND
NC
10
11
ECG1_LA
ECG2_LL
ECG3_RA 12
13
14
15
16
ECG4_V1
ECG5_V2
AGND
NC
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
NOTES
1. THE EXPOSED PADDLE IS ON THE TOP OF THE PACKAGE;
IT IS CONNECTED TO THE MOST NEGATIVE POTENTIAL, AGND.
NOTES
1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN.
Figure 8. ADAS1000 56-Lead LFCSP Pin Configuration
Figure 7. ADAS1000 64-Lead LQFP Pin Configuration
1
2
42
41
40
39
38
37
36
35
34
33
32
31
30
29
AGND
ECG5_V2
ECG4_V1
ECG3_RA
ECG2_LL
ECG1_LA
REFIN
REFOUT
REFGND
NC
DGND
PIN 1
INDICATOR
IOVDD
GPIO0/MCS
GPIO1/MSCLK
GPIO2/MSDO
GPIO3
DGND
CS
DRDY
SDI
SCLK
SDO
IOVDD
DGND
3
4
5
ADAS1000-1
6
56-LEAD LFCSP
7
8
TOP VIEW
(Not to Scale)
9
10
11
12
13
14
NC
NC
NC
AGND
NOTES
1. THE EXPOSED PADDLE IS ON THE TOP OF THE PACKAGE;
IT IS CONNECTED TO THE MOST NEGATIVE POTENTIAL, AGND.
Figure 9. ADAS1000-1 56-Lead LFCSP Pin Configuration
Rev. B | Page 14 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
1
2
NC
NC
PIN 1
AGND
DGND
IOVDD
SDO
42
41
40
39
38
37
36
DGND
IOVDD
GPIO0
GPIO1
GPIO2
GPIO3
DGND
1
2
PIN 1
AGND
ECG5
ECG4
ECG3
ECG2
ECG1
REFIN
REFOUT
REFGND
NC
INDICATOR
3
NC
NC
3
4
4
5
SCLK
SDI
NC
5
ADAS1000-2
6
NC
6
56-LEAD LFCSP
7
DRDY
CS
REFGND
REFOUT
REFIN
ECG1
7
ADAS1000-2
35 CS
34 DRDY
33 SDI
32 SCLK
31 SDO
30 IOVDD
29 DGND
64-LEAD LQFP
8
8
TOP VIEW
(Not to Scale)
9
9
DGND
GPIO3
GPIO2
GPIO1
GPIO0
IOVDD
DGND
NC
TOP VIEW
(Not to Scale)
10
11
12
13
10
NC
NC
NC
ECG2 11
ECG3
ECG4
ECG5
AGND
NC
12
13
14
15
16
AGND 14
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
NOTES
1. THE EXPOSED PADDLE IS ON THE TOP OF THE PACKAGE;
IT IS CONNECTED TO THE MOST NEGATIVE POTENTIAL, AGND.
2. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN.
NOTES
1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN.
Figure 10. ADAS1000-2 Companion 64-Lead LQFP Pin Configuration
Figure 11. ADAS1000-2 Companion 56-Lead LFCSP Pin Configuration
Table 9. Pin Function Descriptions
ADAS1000
ADAS1000-1
ADAS1000-2
LQFP
LFCSP
LFCSP
LQFP
LFCSP
Mnemonic
Description
18, 23,
58, 63
15, 20,
51, 56
15, 20, 51, 56
18, 23,
58, 63
15, 20,
51, 56
AVDD
Analog Supply. See recommendations for bypass capacitors in the Power
Supply, Grounding, and Decoupling Strategy section.
35, 46
30, 41
30, 41
23, 48
35, 46
30, 41
IOVDD
Digital Supply for Digital Input/Output Voltage Levels. See recommendations
for bypass capacitors in the Power Supply, Grounding, and Decoupling
Strategy section.
26, 55
23, 48
26, 55
23, 48
ADCVDD
Analog Supply for ADC. There is an on-chip linear regulator providing the
supply voltage for the ADCs. This pin is primarily provided for decoupling
purposes; however, the pin may also be supplied by an external 1.8 V supply if
the user wants to use a more efficient supply to minimize power dissipation.
In this case, use the VREG_EN pin tied to ground to disable the ADCVDD
and DVDD regulators. Do not use the ADCVDD to supply other functions.
See recommendations for bypass capacitors in the Power Supply,
Grounding, and Decoupling Strategy section.
30, 51
27, 44
27, 44
30, 51
27, 44
DVDD
Digital Supply. There is an on-chip linear regulator providing the supply
voltage for the digital core. This pin is primarily provided for decoupling
purposes; however, the pin can also be overdriven, supplied by an
external 1.8 V supply if the user wants to use a more efficient supply to
minimize power dissipation. In this case, use the VREG_EN pin tied to
ground to disable the ADCVDD and DVDD regulators. See recommendations
for bypass capacitors in the Power Supply, Grounding, and Decoupling
Strategy section.
2, 15,
24, 25,
56, 57
1, 14,
21, 22,
49, 50
1, 14, 21, 22,
49, 50
2, 15,
24, 25,
56, 57
1, 14, 21,
22, 49,
50
AGND
Analog Ground.
31, 34,
40, 47,
50
28, 29,
36, 42,
43
28, 29, 36, 42,
43
31, 34,
40, 47,
50
28, 29,
36, 42,
43
DGND
Digital Ground.
59
19
19
59
19
VREG_EN
Enables or disables the internal voltage regulators used for ADCVDD and
DVDD. Tie this pin to AVDD to enable or tie this pin to ground to disable
the internal voltage regulators.
10
11
12
13
14
6
5
4
3
2
6
5
4
3
2
ECG1_LA
ECG2_LL
ECG3_RA
ECG4_V1
ECG5_V2
Analog Input, Left Arm (LA).
Analog Input, Left Leg (LL).
Analog Input, Right Arm (RA).
Analog Input, Chest Electrode 1 or Auxiliary Biopotential Input (V1).
Analog Input, Chest Electrode 2 or Auxiliary Biopotential Input (V2).
Rev. B | Page 15 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
ADAS1000
LQFP LFCSP
ADAS1000-1
LFCSP
ADAS1000-2
LQFP
LFCSP
Mnemonic
ECG1
Description
10
11
12
13
14
6
5
4
3
2
Analog Input 1.
ECG2
Analog Input 2.
ECG3
Analog Input 3.
ECG4
Analog Input 4.
ECG5
Analog Input 5.
4
12
11
10
16
EXT_RESP_RA
EXT_RESP_LL
EXT_RESP_LA
RESPDAC_LL
Optional External Respiration Input.
Optional External Respiration Input.
Optional External Respiration Input.
5
6
62
Optional path for higher performance respiration resolution, respiration
DAC drive, Negative Side 0.
60
18
SHIELD/
Shared Pin (User-Configured).
RESPDAC_LA
Output of Shield Driver (SHIELD).
Optional Path for Higher Performance Respiration Resolution, Respiration
DAC Drive, Negative Side 1 (RESPDAC_LA).
3
13
52
RESPDAC_RA
CM_OUT/WCT
Optional Path for Higher Performance Respiration Resolution, Respiration
DAC Drive, Positive Side.
22
52
Common-Mode Output Voltage (Average of Selected Electrodes). Not
intended to drive current.
19
21
20
61
55
53
54
17
55
53
54
17
19
21
55
53
CM_IN
Common-Mode Input.
RLD_SJ
Summing Junction for Right Leg Drive Amplifier.
Output and Feedback Junction for Right Leg Drive Amplifier.
RLD_OUT
CAL_DAC_IO
Calibration DAC Input/Output. Output for a master device, input for a
slave. Not intended to drive current.
9
7
7
9
7
REFIN
Reference Input. For standalone mode, use REFOUT connected to REFIN.
External 10 μF with ESR < 0.2 Ω in parallel with 0.1 μF bypass capacitors to
GND are required and must be placed as close to the pin as possible. An
external reference can be connected to REFIN.
8
8
8
8
7
8
9
REFOUT
Reference Output.
7
9
9
REFGND
Reference Ground. Connect to a clean ground.
27, 28
47, 46
47, 46
XTAL1, XTAL2
External crystal connects between these two pins; apply external clock
drive to CLK_IO. Each XTAL pin requires 15 pF to ground.
29
41
44
45
35
32
45
35
32
CLK_IO
CS
Buffered Clock Input/Output. Output for a master device; input for a slave.
Powers up in high impedance.
41
44
35
32
CS
Chip Select and Frame Sync, Active Low. can be used to frame each
word or to frame the entire suite of data in framing mode.
SCLK
Clock Input. Data is clocked into the shift register on a rising edge and
clocked out on a falling edge.
43
53
45
33
25
31
33
25
31
43
53
45
33
25
31
SDI
PD
Serial Data Input.
Power-Down, Active Low.
SDO
Serial Data Output. This pin is used for reading back register configuration
data and for the data frames.
42
34
34
42
34
DRDY
Digital Output. This pin indicates that conversion data is ready to be read
back when low, busy when high. When reading packet data, the entire
DRDY
packet must be read to allow
to return high.
54
52
24
26
24
26
54
52
24
26
RESET
Digital Input. This pin has an internal pull-up. This pin resets all internal
nodes to their power-on reset values.
SYNC_GANG
Digital Input/Output (Output on Master, Input on Slave). Used for
synchronization control where multiple devices are connected together.
Powers up in high impedance.
36
37
38
39
40
39
38
37
40
39
38
37
MCS
CS
General-Purpose I/O or Master 128 kHz SPI .
GPIO0/
GPIO1/MSCLK
GPIO2/MSDO
GPIO3
General-Purpose I/O or Master 128 kHz SPI SCLK.
General-Purpose I/O or Master 128 kHz SPI SDO.
General-Purpose I/O.
Rev. B | Page 16 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
ADAS1000
ADAS1000-1
LFCSP
ADAS1000-2
LQFP
LFCSP
LQFP
1, 3, 4,
LFCSP
Mnemonic
Description
1, 16,
10, 11, 12,
13, 16
10, 11,
NC
No connect. Do not connect to these pins (see Figure 7, Figure 9,
Figure 10, and Figure 11).
17, 32,
33, 48,
49, 64
5, 6, 16, 12, 13,
17, 20,
22, 27,
28, 32,
33, 48,
49, 60,
62, 64
16, 18,
46, 47,
52, 54
36
37
38
39
40
39
38
37
GPIO0
General-Purpose I/O.
General-Purpose I/O.
General-Purpose I/O.
General-Purpose I/O.
Output of Shield Driver.
GPIO1
GPIO2
GPIO3
18
57
SHIELD
CAL_DAC_IN
61
29
17
Calibration DAC Input. Input for companion device. Calibration signal
comes from the master.
45
57
CLK_IN
EPAD
Buffered Clock Input. Drive this pin from the master CLK_IO pin.
57
Exposed Pad. The exposed paddle is on the top of the package; it is
connected to the most negative potential, AGND.
Rev. B | Page 17 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
8
15
10
5
0.5Hz TO 40Hz
GAIN SETTING 0 = 1.4
DATA RATE = 2kHz
10 SECONDS OF DATA
6
4
2
0
0
–5
–10
–15
–2
–4
–6
0.5Hz TO 150Hz
GAIN SETTING 3 = 4.2
DATA RATE = 2kHz
10 SECONDS OF DATA
0
1
2
3
4
5
6
7
8
9
10
0
1
2
3
4
5
6
7
8
9
10
TIME (Seconds)
TIME (Seconds)
Figure 12. Input Referred Noise for 0.5 Hz to 40 Hz Bandwidth, 2 kHz Data
Rate, GAIN 0 (1.4)
Figure 15. Input Referred Noise for 0.5 Hz to 150 Hz Bandwidth, 2 kHz Data
Rate, GAIN 3 (4.2)
8
25
0.5Hz TO 40Hz
LA 150Hz
LA 40Hz
GAIN SETTING 3 = 4.2
DATA RATE = 2kHz
6
10 SECONDS OF DATA
20
15
10
5
4
2
0
–2
–4
–6
0
0
1
2
3
4
5
6
7
8
9
10
GAIN 0
GAIN 1
GAIN 2
GAIN 3
TIME (Seconds)
GAIN SETTING
Figure 13. Input Referred noise for 0.5 Hz to 40 Hz Bandwidth, 2 kHz Data
Rate, GAIN 3 (4.2)
Figure 16. ECG Channel Noise Performance over a 0.5 Hz to 40 Hz or 0.5 Hz to
150 Hz Bandwidth vs. Gain Setting
15
10
5
0.020
AVDD = 3.3V
GAIN SETTING 0 = 1.4
0.018
0.016
0.014
0.012
0.010
0
–5
–10
–15
0.5Hz TO 150Hz
GAIN SETTING 0 = 1.4
DATA RATE = 2kHz
10 SECONDS OF DATA
0
1
2
3
4
5
6
7
8
9
10
LA
LL
RA
V1
V2
ELECTRODE INPUT
TIME (Seconds)
Figure 14. Input Referred Noise for 0.5 Hz to 150 Hz Bandwidth,
2 kHz Data Rate, GAIN 0 (1.4)
Figure 17. Typical Gain Error Across Channels
Rev. B | Page 18 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
0.121
0.215
AVDD = 3.3V
AVDD = 3.3V
0.210
0.205
0.200
0.195
0.190
0.101
0.081
0.061
0.041
0.021
0.001
0.185
ECG DC LEAD-OFF THRESHOLD
RLD DC LEAD-OFF THRESHOLD
0.180
GAIN 0
GAIN 1
GAIN 2
GAIN 3
–40
–20
0
20
40
60
80
GAIN SETTING
TEMPERATURE (°C)
Figure 18. Typical Gain Error vs. Gain
Figure 21. DC Lead-Off Comparator Low Threshold vs. Temperature
0.15
0.10
2.420
AVDD = 3.3V
AVDD = 3.3V
GAIN SETTING 0 = 1.4
GAIN SETTING 1 = 2.1
GAIN SETTING 2 = 2.8
GAIN SETTING 3 = 4.2
2.415
2.410
2.405
2.400
2.395
2.390
2.385
0.05
0
–0.05
–0.10
–0.15
–0.20
–0.25
–0.30
–0.35
GAIN ERROR G0
GAIN ERROR G1
GAIN ERROR G2
GAIN ERROR G3
2.380
ECG DC LEAD-OFF THRESHOLD
RLD DC LEAD-OFF THRESHOLD
2.375
–40
–20
0
20
40
60
80
–40
–20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
Figure 19. Typical Gain Error for All Gain Settings Across Temperature
Figure 22. DC Lead-Off Comparator High Threshold vs. Temperature
5
0
AVDD = 3.3V
GAIN SETTING 0 = 1.4
+85°C
+55°C
+25°C
–5°C
AVDD = 3.3V
4
3
–1
–2
–40°C
2
–3
1
–4
0
–5
–1
–2
–3
–4
–5
–6
–7
–8
–9
–10
0.3
0.8
1.3
1.8
2.3
1
10
100
FREQUENCY (Hz)
1k
VOLTAGE (V)
Figure 20. Typical ECG Channel Leakage Current over Input Voltage Range vs.
Temperature
Figure 23. Filter Response with 40 Hz Filter Enabled, 2 kHz Data Rate; See
Figure 75 for Digital Filter Overview
Rev. B | Page 19 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
0
–1
–2
–3
–4
–5
–6
0
AVDD = 3.3V
–1
–2
–3
–4
–5
–6
–7
–8
–9
–10
AVDD = 3.3V
10
1
100
1k
10k
100k
1
10
100
1k
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 24. Filter Response with 150 Hz Filter Enabled, 2 kHz Data Rate;
See Figure 75 for Digital Filter Overview
Figure 27. Analog Channel Bandwidth
0
–1
–2
–3
–4
–5
–6
–7
–8
–9
0
–1
–2
–3
–4
–5
–6
–7
–8
–9
–10
AVDD = 3.3V
1
10
100
1k
10k
100k
1
10
100
1k
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 25. Filter Response with 250 Hz Filter Enabled, 2 kHz Data Rate;
See Figure 75 for Digital Filter Overview
Figure 28. Filter Response Running at 128 kHz Data Rate; See Figure 75 for
Digital Filter Overview
0
1.8010
1.8005
1.8000
1.7995
1.7990
1.7985
1.7980
1.7975
1.7970
1.7965
AVDD = 3.3V
–1
–2
–3
–4
–5
–6
–7
–8
–9
–10
1
10
100
1k
–40
–20
0
20
40
60
80
FREQUENCY (Hz)
TEMPERATURE (°C)
Figure 26. Filter Response with 450 Hz Filter Enabled, 2 kHz Data Rate;
See Figure 75 for Digital Filter Overview
Figure 29. Typical Internal VREF vs. Temperature
Rev. B | Page 20 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
805
1.3010
AVDD = 3.3V
AVDD = 3.3V
800
795
790
785
780
775
770
765
1.3005
1.3000
1.2995
1.2990
1.2985
1.2980
1.2975
1.2970
–40
–20
0
20
40
60
80
–40
–20
0
40
TEMPERATURE (°C)
60
80
20
TEMPERATURE (°C)
Figure 30. VCM_REF vs. Temperature
Figure 33. Typical AVDD Supply Current vs. Temperature in Standby Mode
12.65
12.50
12.45
12.40
12.35
12.30
12.25
12.20
LOW NOISE/HIGH
AVDD = 3.3V
PERFORMANCE MODE
5 ECG CHANNELS ENABLED
INTERNAL LDO UTILIZED
HIGH PERFORMANCE/LOW NOISE MODE
12.60
12.55
12.50
12.45
12.40
12.35
3.0
3.5
4.0
4.5
5.0
5.5
6.0
–40
–20
0
20
40
60
80
VOLTAGE (V)
TEMPERATURE (°C)
Figure 31. Typical AVDD Supply Current vs. Temperature, Using Internal
ADVCDD/DVDD Supplies
Figure 34. Typical AVDD Supply Current vs. AVDD Supply Voltage
3.430
0.142955
AVDD = 3.3V
AVDD = 3.3V
ECG PATH/DEFIB/CABLE IMPEDANCE = 0 Ω
PATIENT IMPEDANCE = 1kΩ
5 ECG CHANNELS ENABLED
ADCVDD AND DVDD SUPPLIED EXTERNALLY
HIGH PERFORMANCE/LOW NOISE MODE
RESPIRATION RATE = 10RESPPM
RESPAMP = 11 = 60µA p-p
RESPGAIN = 0011 = 4
3.425
0.142950
0.142945
0.142940
0.142935
0.142930
0.142925
3.420
3.415
3.410
3.405
3.400
3.395
–40
–20
0
20
40
60
80
0
5
10
15
20
25
30
TEMPERATURE (°C)
TIME (Seconds)
Figure 32. Typical AVDD Supply Current vs. Temperature, Using Externally
Supplied ADVCDD/DVDD
Figure 35. Respiration with 200 mΩ Impedance Variation, Using Internal
Respiration Paths and Measured with a 0 Ω Patient Cable
Rev. B | Page 21 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
0.121145
0.517390
AVDD = 3.3V
AVDD = 3.3V
ECG PATH/DEFIB/CABLE IMPEDANCE = 5k Ω/250pF
PATIENTIMPEDANCE = 1kΩ
EXTCAP = 100pF
ECG PATH/DEFIB/CABLE IMPEDANCE = 0Ω
PATIENT IMPEDANCE = 1kΩ
RESPIRATION RATE = 10RESPPM
RESPAMP = 11 = 60µA p-p
RESPGAIN = 0011 = 4
0.121140
0.517385 RESPIRATION RATE = 10RESPPM
0.121135
0.121130
0.121125
0.121120
0.121115
0.517380
0.517375
0.517370
0.517365
RESPAMP = 11 = 60µA p-p
RESPGAIN = 0011 = 4
0.517360
0
5
10
15
20
25
30
0
5
10
15
20
25
30
TIME (Seconds)
TIME (Seconds)
Figure 36. Respiration with 100 mΩ Impedance Variation, Using Internal
Respiration Paths and Measured with a 0 Ω Patient Cable
Figure 39. Respiration with 200 mΩ Impedance Variation, Using External
Respiration DAC Driving 100 pF External Capacitor and Measured with a
5 kΩ Patient Cable
0.159775
0.663160
AVDD = 3.3V
AVDD = 3.3V
ECG PATH/DEFIB/CABLE IMPEDANCE = 5k Ω
PATIENT IMPEDANCE = 1kΩ
ECG PATH/DEFIB/CABLE IMPEDANCE = 1.5k Ω/600pF
PATIENT IMPEDANCE = 1kΩ
EXTCAP = 1nF
RESPIRATION RATE = 10RESPPM
RESPAMP = 11 = 60µA p-p
RESPGAIN = 0011 = 4
0.159770
0.159765
0.159760
0.159755
0.159750
0.159745
0.663155
0.663150
0.663145
0.663140
0.663135
0.663130
RESPIRATION RATE = 10RESPPM
RESPAMP = 11
RESPGAIN = 0001 = 1
0
5
10
15
20
25
30
0
5
10
15
20
25
30
TIME (Seconds)
TIME (Seconds)
Figure 37. Respiration with 200 mΩ Impedance Variation, Using Internal
Respiration Paths and Measured with a 5 kΩ Patient Cable
Figure 40. Respiration with 200 mΩ Impedance Variation, Using External
Respiration DAC Driving 1 nF External Capacitor and Measured with a 1.5 kΩ
Patient Cable
0.062365
0.062360
0.062355
0.062350
0.062345
0.159126
AVDD = 3.3V
ECG PATH/DEFIB/CABLE IMPEDANCE = 1.5kΩ/600pF
PATIENT IMPEDANCE = 1kΩ
0.159125
0.159124
0.159123
0.159122
0.159121
0.159120
AVDD = 3.3V
ECG PATH/DEFIB/CABLE IMPEDANCE = 0Ω
PATIENT IMPEDANCE = 1kΩ
0.062340
EXTCAP = 100pF
RESPIRATION RATE = 10RESPPM
RESPAMP = 11 = 60µA p-p
RESPGAIN = 0011 = 4
EXTCAP= 1nF
0.159119
RESPIRATION RATE = 10RESPPM
RESPAMP = 11
RESPGAIN = 0001 = 1
0.062335
0.159118
0
5
10
15
20
25
30
0
5
10
15
20
25
30
TIME (Seconds)
TIME (Seconds)
Figure 38. Respiration with 200 mΩ Impedance Variation, Using External
Respiration DAC Driving 100 pF External Capacitor and Measured with a 0 Ω
Patient Cable
Figure 41. Respiration with 100 mΩ Impedance Variation, Using External
Respiration DAC Driving 1 nF External Capacitor and Measured with a 1.5 kΩ
Patient Cable
Rev. B | Page 22 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
50
150
LA
LL
RA
V1
V2
LA
LL
RA
V1
V2
AVDD = 3.3V
AVDD = 3.3V
40
30
100
50
20
10
0
0
–10
–20
–30
–40
–50
–50
–100
–150
0.3
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
2.1
2.3
0.3
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
2.1
2.3
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Figure 42. DNL vs. Input Voltage Range Across Electrodes at 25°C
Figure 45. INL vs. Input Voltage Across Electrode Channel for 2 kHz Data Rate
150
50
AVDD = 3.3V
GAIN0
GAIN1
GAIN2
GAIN3
–40°C
–5°C
+25°C
+55°C
+85°C
AVDD = 3.3V
40
30
100
50
20
10
0
0
–10
–20
–30
–40
–50
–50
–100
0.3
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
2.1
2.3
0.3
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
2.1
2.3
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Figure 43. DNL vs. Input Voltage Range Across Temperature
Figure 46. INL vs. Input Voltage Across Gain Setting for 16 kHz Data Rate
150
150
AVDD = 3.3V
GAIN0
GAIN1
GAIN2
GAIN3
AVDD = 3.3V
GAIN0
GAIN1
GAIN2
GAIN3
100
50
100
50
0
0
–50
–100
–150
–50
–100
–150
0.3
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
2.1
2.3
0.3
0.5
0.7
0.9
1.1
1.3
1.5
1.7
1.9
2.1
2.3
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Figure 44. INL vs. Input Voltage Across Gain Setting for 2 kHz Data Rate
Figure 47. INL vs. Input Voltage Across Gain Setting for 128 kHz Data Rate
Rev. B | Page 23 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
0
120
100
80
AVDD = 3.3V
GAIN 0
–20
–40
DATA RATE = 2kHz
FILTER SETTING = 150Hz
60
–60
40
–80
20
–100
–120
–140
–160
–180
0
–20
–40
–60
–80
100m
1
10
100
1k
10k 100k 1M 10M 100M 1G
0
50
100 150 200 250 300 350 400 450 500
FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 51. Open-Loop Gain Response of ADAS1000 Right Leg Drive Amplifier
Without Loading
Figure 48. FFT with 60 Hz Input Signal
150
0
AVDD = 3.3V
–0.5dBFS
10Hz INPUT SIGNAL
–50
–100
–150
–200
–250
–300
–350
100
50
SNR
0
–50
–100
THD
GAIN 0
GAIN 1
GAIN 2
GAIN 3
100m
1
10
100
1k
10k 100k 1M 10M 100M 1G
GAIN SETTING
FREQUENCY (Hz)
Figure 52. Open-Loop Phase Response of ADAS1000 Right Leg Drive Amplifier
Without Loading
Figure 49. SNR and THD Across Gain Settings
AVDD = 3.3V
DRDY
AVDD
2
1
CH1 2.00V
M1.00ms
22.1%
A CH1
2.48V
CH2 1.00V
T
DRDY
Figure 50. Power Up AVDD Line to
Going Low (Ready)
Rev. B | Page 24 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
APPLICATIONS INFORMATION
diagnostic applications. Value-added cardiac post processing
can be executed externally on a DSP, microprocessor, or FPGA.
The ADAS1000/ADAS1000-1/ADAS1000-2 are designed for
operation in both low power, portable telemetry applications
and line powered systems; therefore, the parts offer power/noise
scaling to ensure suitability to these varying requirements.
OVERVIEW
The ADAS1000/ADAS1000-1/ADAS1000-2 are electro cardiac
(ECG) front-end solutions targeted at a variety of medical appli-
cations. In addition to ECG measurements, the ADAS1000 version
also measures thoracic impedance (respiration) and detects
pacing artifacts, providing all the measured information to the
host controller in the form of a data frame supplying either
lead/vector or electrode data at programmable data rates. The
ADAS1000/ADAS1000-1/ADAS1000-2 are designed to simplify
the task of acquiring ECG signals for use in both monitor and
The devices also offer a suite of dc and ac test excitation via
a calibration DAC feature and CRC redundancy checks in
addition to readback of all relevant register address space.
REFIN REFOUT CAL_DAC_IO RLD_SJ
RLD_OUT CM_IN
CM_OUT/WCT
SHIELD
AVDD
IOVDD
DRIVEN
LEAD
SHIELD
DRIVE
AMP
VREF
AMP
ADCVDD
DVDD
ADCVDD, DVDD
1.8V
REGULATORS
–
CALIBRATION
DAC
+
+
–
VCM_REF
(1.3V)
ADAS1000
RESPIRATION
DAC
COMMON-
MODE AMP
VCM
AC
AC
LEAD-OFF
DAC
LEAD-OFF
DETECTION
VREF
PACE
DETECTION
DC LEAD-
OFF/MUXES
ECG PATH
AMP
ECG1_LA
ADC
ADC
ADC
ADC
ADC
CS
ECG2_LL
ECG3_RA
ECG4_V1
ECG5_V2
SCLK
SDI
AMP
AMP
AMP
AMP
SDO
FILTERS,
CONTROL,
AND
INTERFACE
LOGIC
DRDY
PD
RESET
SYNC_GANG
GPIO0/MCS
GPIO1/MSCLK
GPIO2/MSDO
GPIO3
EXT_RESP_LA
EXT_RESP_LL
AMP
ADC
EXT_RESP_RA
RESPDAC_LA
MUX
CLOCK GEN/OSC/
EXTERNAL CLK
SOURCE
CLK_IO
RESPIRATION PATH
RESPDAC_LL
RESPDAC_RA
XTAL1 XTAL2
REFGND
AGND
DGND
Figure 53. ADAS1000 Simplified Block Diagram
Rev. B | Page 25 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
REFIN REFOUT CAL_DAC_IO RLD_SJ
RLD_OUT CM_IN
CM_OUT/WCT
SHIELD
AVDD
IOVDD
DRIVEN
LEAD
AMP
VREF
SHIELD
DRIVE
AMP
ADCVDD
DVDD
ADCVDD, DVDD
1.8V
REGULATORS
CALIBRATION
DAC
VCM_REF
(1.3V)
ADAS1000-1
COMMON-
MODE AMP
VCM
AC
LEAD-OFF
DAC
VREF
AC
LEAD-OFF
DETECTION
ECG PATH
ECG1_LA
AMP
AMP
AMP
AMP
AMP
ADC
CS
ECG2_LL
ECG3_RA
ECG4_V1
ECG5_V2
SCLK
SDI
ADC
ADC
ADC
ADC
SDO
FILTERS,
CONTROL,
AND
INTERFACE
LOGIC
DC LEAD-
OFF/MUXES
DRDY
PD
RESET
SYNC_GANG
GPIO0/MCS
GPIO1/MSCLK
GPIO2/MSDO
GPIO3
CLOCK GEN/OSC/
EXTERNAL CLK
SOURCE
CLK_IO
REFGND
AGND
DGND
XTAL1 XTAL2
Figure 54. ADAS1000-1 Simplified Block Diagram
Rev. B | Page 26 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
AVDD
IOVDD
CM_IN
REFIN REFOUT CAL_DAC_IN
RLD_SJ
VREF
ADCVDD, DVDD
1.8V
REGULATORS
ADCVDD
DVDD
COMMON-
MODE AMP
AC
LEAD-OFF
DAC
ADAS1000-2
VREF
AC
LEAD-OFF
DETECTION
ECG PATH
ECG1
AMP
AMP
AMP
AMP
AMP
ADC
CS
ECG2
ECG3
ECG4
ECG5
SCLK
SDI
ADC
ADC
ADC
ADC
SDO
DRDY
FILTERS,
CONTROL,
AND
DC LEAD-
OFF/MUXES
INTERFACE
LOGIC
PD
RESET
SYNC_GANG
GPIO0
GPIO1
GPIO2
GPIO3
REFGND
AGND
DGND
Figure 55. ADAS1000-2 Slave Device Simplified Block Diagram
Rev. B | Page 27 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
ADAS1000-1/ADAS1000-2. Note that in 128 kHz data rate, lead
data is only available when configured in analog lead mode, as
shown in Figure 58. Digital lead mode is not available for this
data rate.
ECG INPUTS—ELECTRODES/LEADS
The ADAS1000/ADAS1000-1/ADAS1000-2 ECG product
consists of 5 ECG inputs and a reference drive, RLD (right leg
drive). In a typical 5-lead/vector application, four of the ECG
inputs (ECG3_RA, ECG1_LA, ECG2_LL, ECG4_V1) are used
in addition to the RLD path. This leaves one spare ECG path
(which can be used for other purposes, such as calibration or
temperature measurement). Both V1 and V2 input channels can
be used for alternative measurements, if desired. When used in
this way, the negative terminal of the input stage can be switched to
the fixed internal VCM_REF = 1.3 V; see details in Table 50.
A 12-lead (10-electrode) system can be achieved using one
ADAS1000 or ADAS1000-1 device ganged together with one
ADAS1000-2 slave device as described in the Gang Mode
Operation section. Here, 9 ECG electrodes and one RLD
electrode achieve the 10 electrode system, again leaving one
spare ECG channel that can be used for alternate purposes as
suggested previously. In such a system, having nine dedicated
electrodes benefits the user by delivering lead information
based on electrode measurements and calculations rather
than deriving leads from other lead measurements.
In a 5-lead system, the ADAS1000/ADAS1000-1/ADAS1000-2
can provide Lead I, Lead II, and Lead III data or electrode data
directly via the serial interface at all frame rates. The other ECG
leads can be calculated by the user’s software from either the
lead data or the electrode data provided by the ADAS1000/
Table 10 outlines the calculation of the leads (vector) from the
individual electrode measurements.
Table 10. Lead Composition1
Lead Name
Composition
Equivalent
ADAS1000 or ADAS1000-1
I
LA – RA
II
LL – RA
III
LL – LA
aVR2
aVL2
aVF2
V1’
V2’
V3’
V4’
V5’
V6’
RA – 0.5 × (LA + LL)
LA – 0.5 × (LL + RA)
LL – 0.5 × (LA + RA)
V1 – 0.333 × (LA + RA + LL)
V2 – 0.333 × (LA + RA + LL)
V3 – 0.333 × (LA + RA + LL)
V4 – 0.333 × (LA + RA + LL)
V5 – 0.333 × (LA + RA + LL)
V6 – 0.333 × (LA + RA + LL)
−0.5 × (I + II)
0.5 × (I − III)
0.5 × (II + III)
12 Leads Achieved by Adding ADAS1000-2 Slave
1 These lead compositions apply when the master ADAS1000 device is configured into lead mode (analog lead mode or digital lead mode) with VCM = WCT = (RA + LA
+ LL)/3. When configured for 12-lead operation with a master and slave device, the VCM signal derived on the master device (CM_OUT) is applied to the CM_IN of the
slave device. For correct operation of the slave device, the device must be configured in electrode mode (see the FRMCTL register in Table 37).
2 These augmented leads are not calculated within the ADAS1000, but can be derived in the host DSP/microcontroller/FPGA.
Rev. B | Page 28 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
selected electrodes to the internal 1.3 V level, VCM_REF,
maximizing each channel’s available signal range.
ECG CHANNEL
The ECG channel consists of a programmable gain, low noise,
differential preamplifier; a fixed gain anti-aliasing filter; buffers;
and an ADC (see Figure 56). Each electrode input is routed to
its PGA noninverting input. Internal switches allow the inverting
inputs of the PGA to be connected to other electrodes and/or
the Wilson central terminal (WCT) to provide differential
analog processing (analog lead mode), to a computed average of
some or all electrodes, or the internal 1.3 V common-mode
reference (VCM_REF). The latter two modes support digital
lead mode (leads computed on-chip) and electrode mode (leads
calculated off-chip). In all cases, the internal reference level is
removed from the final lead data.
All ECG channel amplifiers use chopping to minimize 1/f noise
contributions in the ECG band. The chopping frequency of
~250 kHz is well above the bandwidth of any signals of interest.
The 2-pole anti-aliasing filter has ~65 kHz bandwidth to support
digital pace detection while still providing greater than 80 dB of
attenuation at the ADC’s sample rate. The ADC itself is a 14-bit,
2 MHz SAR converter; 1024 × oversampling helps achieve the
required system performance. The full-scale input range of the
ADC is 2 × VREF, or 3.6 V, although the analog portion of the
ECG channel limits the useful signal swing to about 2.8 V. The
ADAS1000 contains flags to indicate whether the ADC data is
out of range, indicating a hard electrode off state. Programmable
overrange and underrange thresholds are shown in the LOFFUTH
and LOFFLTH registers (see Table 39 and Table 40, respectively).
The ADC out of range flag is contained in the header word (see
Table 54).
The ADAS1000/ADAS1000-1/ADAS1000-2 implementation
uses a dc-coupled approach, which requires that the front end
be biased to operate within the limited dynamic range imposed
by the relatively low supply voltage. The right leg drive loop
performs this function by forcing the electrical average of all
ADAS1000
TO COMMON-MODE AMPLIFIER
FOR DRIVEN LEG AND
SHIELD DRIVER
AVDD
PREAMP
fS
VREF
G = 1, 1.5, 2, 3
PATIENT
CABLE
DIFF AMP
BUFFER
G = 1.4
EXTERNAL
RFI AND DEFIB
PROTECTION
FILTER
+
–
ELECTRODE
ELECTRODE
ADC
14
ELECTRODE
EXTERNAL
RFI AND DEFIB
PROTECTION
VCM
SHIELD DRIVER
Figure 56. Simplified Schematic of a Single ECG Channel
Rev. B | Page 29 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Digital Lead Mode and Calculation
ELECTRODE/LEAD FORMATION AND INPUT
STAGE CONFIGURATION
When the ADAS1000/ADAS1000-1/ADAS1000-2 are configured
for digital lead mode (see the FRMCTL register, Register 0x0A[4],
Table 37), the digital core calculates each lead from the electrode
signals. This is straightforward for Lead I/ Lead II/Lead III.
Calculating V1’ and V2’ requires WCT, which is also computed
internally for this purpose. This mode ignores the common-
mode configuration specified in the CMREFCTL register
(Register 0x05). Digital lead calculation is only available in
2 kHz and 16k Hz data rates (see Figure 59).
The input stage of the ADAS1000/ADAS1000-1/ADAS1000-2
can be arranged in several different manners. The input amplifi-
ers are differential amplifiers and can be configured to generate
the leads in the analog domain, before the ADCs. In addition
to this, the digital data can be configured to provide either
electrode or lead format under user control as described in
Table 37. This allows maximum flexibility of the input stage
for a variety of applications.
Electrode Mode: Single-Ended Input Electrode
Configuration
Analog Lead Mode and Calculation
Leads are configured in the analog input stage when CHCONFIG
= 1, as shown in Figure 58. This uses a traditional in-amp structure
where lead formation is performed prior to digitization, with
WCT created using the common-mode amplifier. While this
results in the inversion of Lead II in the analog domain, this is
digitally corrected so output data have the proper polarity.
In this mode, the electrode data are digitized relative to the
common-mode signal, VCM, which can be arranged to be any
combination of the contributing ECG electrodes. Common-
mode generation is controlled by the CMREFCTL register as
described in Table 32 (see Figure 61).
Electrode Mode: Common Electrode A and Electrode B
Configurations
In this mode, all electrodes are digitized relative to a common
electrode, for example, RA. Standard leads must be calculated by
post processing the output data of the ADAS1000/ADAS1000-1/
ADAS1000-2 (see Figure 60 and Figure 62).
0x0A 0x01 0x05
MODE
COMMENT
WORD1
WORD2
WORD3
WORD4
WORD5
1
2
3
[8]
[4]
[10]
LEAD I
(LA − RA)
LEAD II
(LL − RA)
LEAD III
(LL − LA)
V1’
(V1 − VCM)
V2’
(V2 − VCM)
ANALOG LEAD
ANALOG LEAD
0
1
0
0
DIGITAL LEAD
SINGLE-ENDED
INPUT, DIGITALLY
CALCULATED LEADS
LEAD I
LEAD II
LEAD III
V1’
V2’
0
0
0
0
4
4
(LA − RA)
(LL − RA)
(LL − LA)
(V1 − WCT )
(V2 − WCT )
COMMON
COMMON
LEAD I
LEAD II
V3’
V1’
V2’
1
ELECTRODE A
ELECTRODE (CE)
LEADS (HERE RA
ELECTRODE IS
CONNECTED TO THE
CE ELECTRODE
(CM_IN) AND V3 IS ON
ECG3 INPUT)
(LA − RA)
(LL − RA)
(V3 – RA) − (LA − RA) − (LL − RA) (V1 − RA) − (LA − RA) + (LL − RA) (V2 − RA) − (LA − RA) + (LL − RA)
3
3
3
SINGLE-ENDED
INPUT
SINGLE-ENDED
INPUT ELECTRODE
RELATIVE TO VCM
LA − VCM
LA − CE
LL − VCM
LL − CE
RA − VCM
V1 − CE
V1 − VCM
V2 − CE
V2 − VCM
V3 − CE
1
1
0
0
0
1
ELECTRODE
COMMON
ELECTRODE B
LEADS FORMED
RELATIVE TO A
COMMON
ELECTRODE (CE)
1
2
3
4
REGISTER FRMCTL, BIT DATAFMT: 0 = LEAD/VECTOR MODE; 1 = ELECTRODE MODE.
REGISTER ECGCTL, BIT CHCONFIG: 0 = SINGLE ENDED INPUT (DIGITAL LEAD MODE OR ELECTRODE MODE); 1 = DIFFERENTIAL INPUT (ANALOG LEAD MODE).
REGISTER CMREFCTL, BIT CEREFEN: 0 = CE DISABLED; 1 = CE ENABLED.
WILSON CENTRAL TERMINAL (WCT) = (RA + LA + LL)/3, THIS IS A DIGITALLY CALCULATED WCT BASED ON THE RA, LA, LL MEASUREMENTS.
Figure 57. Electrode and Lead Configurations
Rev. B | Page 30 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
VCM = WCT = (LA + LL + RA)/3
CM_OUT/WCT
COMMON-
MODE AMP
LEAD I
ECG1_LA
ECG2_LL
ECG3_RA
ECG4_V1
ECG5_V2
+
(LA – RA)
ADC
AMP
–
LEAD III
(LL – LA)
+
AMP
–
ADC
LEAD II
(LL – RA)*
+
AMP
–
ADC
*GETS MULITPLED
BY –1 IN DIGITAL
+
AMP
–
V1’ = V1 – WCT
ADC
WCT = (LA + LL + RA)/3
+
AMP
–
V2’ = V2 – WCT
ADC
WCT = (LA + LL + RA)/3
CM_IN
FOR EXAMPLE RA
COMMON
ELECTRODE CE IN
0x0A 0x01 0x05
MODE
COMMENT
WORD1
WORD2
WORD3
WORD4
WORD5
1
2
3
[8]
[4]
[10]
LEAD I
(LA − RA)
LEAD II
(LL − RA)
LEAD III
(LL − LA)
V1’
(V1 − VCM)
V2’
(V2 − VCM)
ANALOG LEAD
ANALOG LEAD
0
1
0
1
REGISTER FRMCTL, BIT DATAFMT: 0 = LEAD/VECTOR MODE; 1 = ELECTRODE MODE.
2
3
REGISTER ECGCTL, BIT CHCONFIG: 0 = SINGLE ENDED INPUT (DIGITAL LEAD MODE OR ELECTRODE MODE); 1 = DIFFERENTIAL INPUT (ANALOG LEAD MODE).
REGISTER CMREFCTL, BIT CEREFEN: 0 = CE DISABLED; 1 = CE ENABLED.
Figure 58. Electrode and Lead Configurations, Analog Lead Mode
VCM = WCT = (LA + LL + RA)/3
CM_OUT/WCT
COMMON-
MODE AMP
LEAD I
ECG1_LA
ECG 2_LL
ECG3_RA
ECG4_V1
ECG5_V2
+
LA – RA
ADC
ADC
AMP
–
LEAD II
LL – RA
+
AMP
–
LEAD III
LL – LA
DIGITAL DOMAIN
CALCULATIONS
+
AMP
–
ADC
ADC
ADC
+
AMP
–
V1 – WCT
V2 – WCT
+
AMP
–
CM_IN
FOR EXAMPLE, RA
COMMON
ELECTRODE CE IN
0x0A 0x01 0x05
MODE
COMMENT
WORD1
WORD2
WORD3
WORD4
WORD5
[4]1 [10]2
[8]3
DIGITAL LEAD
SINGLE-ENDED
INPUT, DIGITALLY
CALCULATED LEADS
LEAD I
(LA − RA)
LEAD II
(LL − RA)
LEAD III
(LL − LA)
V1’
(V1 − WCT4)
V2’
(V2 − WCT4)
0
0
0
1REGISTER FRMCTL, BIT DATAFMT: 0 = LEAD/VECTOR MODE; 1 = ELECTRODE MODE.
2REGISTER ECGCTL, BIT CHCONFIG: 0 = SINGLE ENDED INPUT (DIGITAL LEAD MODE OR ELECTRODE MODE); 1 = DIFFERENTIAL INPUT (ANALOG LEAD MODE).
3REGISTER CMREFCTL, BIT CEREFEN: 0 = CE DISABLED; 1 = CE ENABLED.
4WILSON CENTRAL TERMINAL (WCT) = (RA + LA + LL)/3, THIS IS A DIGITALLY CALCULATED WCT BASED ON THE RA, LA, LL MEASUREMENTS.
Figure 59. Electrode and Lead Configurations, Digital Lead Mode
Rev. B | Page 31 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
VCM = RA
CM_OUT/WCT
COMMON-
MODE AMP
ECG1_LA
ECG2_LL
+
LEAD I
LEAD II
ADC
ADC
ADC
ADC
ADC
AMP
–
+
AMP
–
DIGITAL DOMAIN
CALCULATIONS
+
AMP
–
V3’
V1’
V2’
ECG3_RA = V3
ECG4_V1
+
AMP
–
+
AMP
–
ECG5_V2
CM_IN = RA
COMMON
ELECTRODE CE IN
0x0A 0x01 0x05
MODE
COMMENT
WORD1
WORD2
WORD3
WORD4
WORD5
[4]1 [10]2
[8]3
COMMON
ELECTRODE A
COMMON
LEAD I
LEAD II
V3’
V1’
V2’
0
0
1
ELECTRODE (CE)
LEADS (HERE RA
ELECTRODE IS
CONNECTED TO THE
CE ELECTRODE
(CM_IN) AND V3 IS ON
ECG3 INPUT)
(LA − RA)
(LL − RA)
(V3 – RA) − (LA − RA) − (LL − RA) (V1 − RA) − (LA − RA) + (LL − RA) (V2 − RA) − (LA − RA) + (LL − RA)
3
3
3
1REGISTER FRMCTL, BIT DATAFMT: 0 = LEAD/VECTOR MODE; 1 = ELECTRODE MODE.
2REGISTER ECGCTL, BIT CHCONFIG: 0 = SINGLE ENDED INPUT (DIGITAL LEAD MODE OR ELECTRODE MODE); 1 = DIFFERENTIAL INPUT (ANALOG LEAD MODE).
3REGISTER CMREFCTL, BIT CEREFEN: 0 = CE DISABLED; 1 = CE ENABLED.
Figure 60. Electrode and Lead Configurations, Common Electrode A
VCM = ( LA+ LL + RA + V1)/
4 IN THIS CASE
CM_OUT/WCT
VCM COMMON MODE
CAN BE ANY COMBINATION
OF ELECTRODES
COMMON-
MODE AMP
ECG1_LA
ECG 2_LL
ECG3_RA
ECG4_V1
ECG5_V2
+
LA – VCM
LL – VCM
ADC
ADC
AMP
–
+
AMP
–
+
AMP
–
RA – VCM
V1 – VCM
V2 – VCM
ADC
ADC
ADC
+
AMP
–
+
AMP
–
CM_IN
FOR EXAMPLE, RA
COMMON
ELECTRODE CE IN
0x0A 0x01 0x05
MODE
COMMENT
WORD1
WORD2
WORD3
WORD4
WORD5
[4]1 [10]2
[8]3
SINGLE-ENDED
INPUT
ELECTRODE
SINGLE-ENDED
INPUT ELECTRODE
RELATIVE TO VCM
LA − VCM
LL − VCM RA − VCM
V1 − VCM
V2 − VCM
1
0
0
1REGISTER FRMCTL, BIT DATAFMT: 0 = LEAD/VECTOR MODE; 1 = ELECTRODE MODE.
2REGISTER ECGCTL, BIT CHCONFIG: 0 = SINGLE ENDED INPUT (DIGITAL LEAD MODE OR ELECTRODE MODE); 1 = DIFFERENTIAL INPUT (ANALOG LEAD MODE).
3REGISTER CMREFCTL, BIT CEREFEN: 0 = CE DISABLED; 1 = CE ENABLED.
Figure 61. Electrode and Lead Configurations, Single-Ended Input Electrode
Rev. B | Page 32 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
VCM = CE = RA
CM_OUT/WCT
COMMON-
MODE AMP
ECG1_LA
ECG2_LL
+
LA – RA
ADC
AMP
–
+
AMP
–
LL – RA
ADC
+
V3 – RA
ADC
ECG3_RA = V3
ECG4_V1
AMP
–
+
AMP
–
V1 – RA
ADC
+
AMP
–
ECG5_V2
V2 – RA
ADC
CM_IN = RA
COMMON
ELECTRODE CE IN
0x0A 0x01 0x05
MODE
COMMENT
WORD1
WORD2
WORD3
WORD4
WORD5
[4]1 [10]2
[8]3
COMMON
ELECTRODE B
LEADS FORMED
RELATIVE TO A
COMMON
LA − CE
LL − CE
V1 − CE
V2 − CE
V3 − CE
1
0
1
ELECTRODE (CE)
1REGISTER FRMCTL, BIT DATAFMT: 0 = LEAD/VECTOR MODE; 1 = ELECTRODE MODE.
2REGISTER ECGCTL, BIT CHCONFIG: 0 = SINGLE ENDED INPUT (DIGITAL LEAD MODE OR ELECTRODE MODE); 1 = DIFFERENTIAL INPUT (ANALOG LEAD MODE).
3REGISTER CMREFCTL, BIT CEREFEN: 0 = CE DISABLED; 1 = CE ENABLED.
Figure 62. Electrode and Lead Configurations, Common Electrode B
Rev. B | Page 33 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
ESIS FILTERING
DEFIBRILLATOR PROTECTION
The ADAS1000/ADAS1000-1/ADAS1000-2 do not include
electrosurgical interference suppression (ESIS) protection on
chip. Any ESIS protection required by the application requires
external components.
The ADAS1000/ADAS1000-1/ADAS1000-2 do not include
defibrillation protection on chip. Any defibrillation protection
required by the application requires external components.
Figure 63 and Figure 64 show examples of external defibrillator
protection, which is required on each ECG channel, in
the RLD path and in the CM_IN path if using the CE input
mode. Note that, in both cases, the total ECG path resistance is
assumed to be 5 kΩ. The 22 MΩ resistors shown connected to
RLD are optional and used to provide a safe termination voltage
for an open ECG electrode; they may be larger in value. Note
that, if using these resistors, the dc lead-off feature works best
with the highest current setting.
ECG PATH INPUT MULTIPLEXING
As shown in Figure 65, signal paths for numerous functions are
provided on each ECG channel (except respiration, which only
connect to the ECG1_LA, ECG2_LL, and ECG3_RA pins).
Note that the channel enable switch occurs after the RLD
amplifier connection, thus allowing the RLD to be connected
(re-directed into any one of the ECG paths). The CM_IN path
is treated the same as the ECG signals.
PATIENT
CABLE
4kΩ
500Ω
500Ω
ECG1
ELECTRODE
AVDD
1
22MΩ
ARGON/NEON
BULB
ADAS1000/
ADAS1000-1/
ADAS1000-2
RLD
1
SP724
500Ω
PATIENT
22MΩ
CABLE
4kΩ
500Ω
AVDD
ELECTRODE
ECG2
ARGON/NEON
BULB
SP724
1
OPTIONAL.
Figure 63. Possible Defibrillation Protection on ECG Paths Using Neon Bulbs
PATIENT
CABLE
4.5kΩ
AVDD
500Ω
ELECTRODE
ECG1
1
22MΩ
2
SP724
ADAS1000/
ADAS1000-1/
ADAS1000-2
RLD
1
22MΩ
PATIENT
CABLE
4.5kΩ
500Ω
ELECTRODE
ECG2
AVDD
2
SP724
1
OPTIONAL.
2
TWO LITTELFUSE SP724 CHANNELS PER ELECTRODE MAY PROVIDE
BEST PROTECTION.
Figure 64. Possible Defibrillation Protection on ECG Paths Using Diode Protection
ACLO
CURRENT
RESPIRATION
INPUT
DCLO
CURRENT
RLD AMP
CALDAC
11.3pF
INPUT AMPLIFIER
ECG PIN
+
–
CHANNEL
ENABLE
TO
FILTERING
MUX FOR LEAD CONFIG,
COMMON ELECTRODE
ANALOG
LEAD
(RA/LA/LL)
+
–
1.3V VCM_REF
VCM
FROM CM
AVERAGING
TO CM
AVERAGING
ADAS1000
Figure 65. Typical ECG Channel Input Multiplexing
Rev. B | Page 34 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
common-mode block. If the physical connection to each
electrode is buffered, these buffers are omitted for clarity.
COMMON-MODE SELECTION AND AVERAGING
The common-mode signal can be derived from any combina-
tion of one or more electrode channel inputs, the fixed internal
common-mode voltage reference, VCM_REF, or an external
source connected to the CM_IN pin. One use of the latter
arrangement is in gang mode where the master device creates
the Wilson central terminal for the slave device or devices. The
fixed reference option is useful when measuring the calibration
DAC test tone signals or while attaching electrodes to the patient,
where it allows a usable signal to be obtained from just two
electrodes.
There are several restrictions on the use of the switches:
If SW1 is closed, SW7 must be open.
If SW1 is open, at least one electrode switch (SW2 to SW7)
must be closed.
SW7 can be closed only when SW2 to SW6 are open, so
that the 1.3 V VCM_REF gets summed in only when all
ECG channels are disconnected.
The CM_OUT output is not intended to supply current or drive
resistive loads, and its accuracy is degraded if it is used to drive
anything other than the slave ADAS1000-2 devices. An external
buffer is required if there is any loading on the CM_OUT pin.
The flexible common-mode generation allows complete
user control over the contributing channels. It is similar to,
but independent of, circuitry that creates the right leg drive
(RLD) signal. Figure 66 shows a simplified version of the
ADAS1000
CM_IN
SW1
SW2
VCM
+
–
CM_OUT
ECG1_LA
SW3
ECG2_LL
SW4
ECG3_RA
SW5
ECG4_V1
SW6
ECG5_V2
SW7
VCM_REF = 1.3V
(WHEN SELECTED, IT GETS
SUMMED IN ON EACH ECG CHANNEL)
Figure 66. Common-Mode Generation Block
Table 11. Truth Table for Common-Mode Selection
ECGCTL
Address
0x011
CMREFCTL Address 0x052
PWREN
DRVCM EXTCM LACM LLCM RACM V1CM V2CM On Switch
Description
0
1
1
1
1
X
X
0
0
0
X
0
0
0
0
X
0
1
1
1
X
0
0
1
1
X
0
0
0
1
X
0
0
0
0
X
0
0
0
0
Powered down, paths disconnected
Internal VCM_REF = 1.3 V is selected
Internal CM selection: LA contributes to VCM
Internal CM selection: LA and LL contribute to VCM
Internal CM selection: LA, LL, and RA contribute to
VCM (WCT)
SW7
SW2
SW2, SW3
SW2, SW3,
SW4
.
.
.
.
.
.
.
.
.
.
1
X
1
X
X
X
X
X
SW1
External VCM selected
1 See Table 28.
2 See Table 32.
Rev. B | Page 35 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
instrument design and cable set. In some cases, adding lead
WILSON CENTRAL TERMINAL (WCT)
compensation proves necessary, while in others, lag compensation
is more appropriate. The summing junction of the RLD amplifier is
brought out to a package pin (RLD_SJ) to facilitate compensation.
The flexibility of the common-mode selection averaging allows
the user to achieve a Wilson central terminal voltage from the
ECG1_LA, ECG2_LL, ECG3_RA electrodes.
The short circuit current capability of the RLD amplifier
exceeds regulatory limits. A patient protection resistor is
required to achieve compliance.
RIGHT LEG DRIVE/REFERENCE DRIVE
The right leg drive amplifier or reference amplifier is used as
part of a feedback loop to force the patient’s common-mode
voltage close to the internal 1.3 V reference level (VCM_REF)
of the ADAS1000/ADAS1000-1/ADAS1000-2. This centers all
the electrode inputs relative to the input span, providing
maximum input dynamic range. It also helps to reject noise
and interference from external sources such as fluorescent
lights or other patient-connected instruments, and absorbs
the dc or ac lead-off currents injected on the ECG electrodes.
Within the RLD block, there is lead-off comparator circuitry
that monitors the RLD amplifier output to determine whether
the patient feedback loop is closed. An open-loop condition,
typically the result of the right leg electrode (RLD_OUT) becoming
detached, tends to drive the output of the amplifier low. This type
of fault is flagged in the header word (see Table 54), allowing the
system software to take action by notifying the user, redirecting the
reference drive to another electrode via the internal switches of
the ADAS1000/ ADAS1000-1/ADAS1000-2, or both. The
detection circuitry is local to the RLD amplifier and remains
functional with a redirected reference drive. Table 32 provides
details on reference drive redirection.
The RLD amplifier can be used in a variety of ways as shown in
Figure 67. Its input can be taken from the CM_OUT signal
using an external resistor. Alternatively, some or all of the
electrode signals can be combined using the internal switches.
The DC gain of the RLD amplifier is set by the ratio of the external
feedback resistor (RFB) to the effective input resistor, which can
be set by an external resistor, or alternatively, a function of the
number of selected electrodes as configured in the CMREFCTL
register (see Table 32). In a typical case, using the internal resistors
for RIN, all active electrodes are used to derive the right leg drive,
resulting in a 2 kΩ effective input resistor. Achieving a typical
dc gain of 40 dB thus requires a 200 kΩ feedback resistor.
While reference drive redirection can be useful in the event that
the right leg electrode cannot be reattached, some precautions
must be observed. Most important is the need for a patient
protection resistor. Because this is an external resistor, it does
not follow the redirected reference drive; some provision for
continued patient protection is needed external to the ADAS1000/
ADAS1000-1/ADAS1000-2. Any additional resistance in the
ECG paths certainly interferes with respiration measurement
and may also result in an increase in noise and decrease in CMRR.
The dynamics and stability of the RLD loop depend on the chosen
dc gain and the resistance and capacitance of the patient cabling.
In general, loop compensation using external components is
required, and must be determined experimentally for any given
The RLD amplifier is designed to stably drive a maximum
capacitance of 5 nF based on the gain configuration (see
Figure 67) and assuming a 330 kΩ patient protection resistor.
EXTERNALLY SUPPLIED COMPONENTS
TO SET RLD LOOP GAIN
CZ
2nF
100kΩ
RZ
40kΩ
IN
4MΩ
RFB*
R
*
RLD_SJ
RLD_OUT
CM_OUT/WCT
ADAS1000
–
+
SW1
10kΩ
10kΩ
10kΩ
10kΩ
10kΩ
ELECTRODE LA
ELECTRODE LL
ELECTRODE RA
ELECTRODE V1
ELECTRODE V2
SW2
SW3
SW4
SW5
SW6
10kΩ
CM_IN OR
CM BUFFER OUT
VCM_REF
(1.3V)
RLD_INT_REDIRECT
*EXTERNAL RESISTOR R IS OPTIONAL. IF DRIVING RLD FROM
IN
THE ELECTRODE PATHS, THEN THE SERIES RESISTANCE WILL
CONTRIBUTE TO THE R IMPEDANCE. WHERE SW1 TO SW5
IN
ARE CLOSED, R = 2kΩ. RFB SHOULD BE CHOSEN
IN
ACCORDINGLY FOR DESIRED RLD LOOP GAIN.
Figure 67. Right Leg Drive—Possible External Component Configuration
Rev. B | Page 36 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
In a typical ECG configuration, the electrodes RA, LA, and LL
are used to generate a common mode of Wilson Central Terminal
(WCT). If one of these electrodes is off, this affects the WCT
signal and any lead measurements that it contributes to. As a
result, the ECG measurements on these signals are expected to
degrade. The user has full control over the common mode
amplifier and can adjust the common-mode configuration to
remove that electrode from the common-mode generation. In
this way, the user can continue to make measurements on the
remaining connected leads.
CALIBRATION DAC
Within the ADAS1000/ADAS1000-1, there are a number of
calibration features.
The 10-bit calibration DAC can be used to correct channel gain
errors (to ensure channel matching) or to provide several test
tones. The options are as follows:
•
DC voltage output (range: 0.3 V to 2.7 V). The DAC
transfer function for dc voltage output is
code
0.3 V+ 2.4 V×
DC Lead-Off Detection
210 −1
This method injects a small programmable dc current into each
input electrode. When an electrode is properly connected, the
current flows into the right leg (RLD_OUT) and produces a
minimal voltage shift. If an electrode is off, the current charges
the capacitance of that pin, causing the voltage at the pin to float
positive and create a large voltage change that is detected by the
comparators in each channel. These comparators use fixed,
gain-independent upper and lower threshold voltages of 2.4 V
and 0.2 V, respectively. If the input exceeds either of these levels,
the lead-off flag is raised. The lower threshold is included in the
event that something pulls the electrode down to ground.
•
•
1 mV p-p sine wave of 10 Hz or 150 Hz
1 mV 1 Hz square wave
Internal switching allows the calibration DAC signals to be
routed to the input of each ECG channel (see Figure 65).
Alternatively, it can be driven out from the CAL_DAC_IO
pin, enabling measurement and correction for external error
sources in the entire ECG signal chain and/or for use as an
input to the ADAS1000-2 companion chip calibration input.
To ensure a successful update of the calibration DAC (see
Table 36), the host controller must issue four additional SCLK
cycles after writing the new calibration DAC register word.
The dc lead-off detection current can be programmed via the
serial interface. Typical currents range from 10 nA to 70 nA in
10 nA steps. All input pins (RA, LA, LL, V1, V2, and CM_IN)
use identical dc lead-off detection circuitry.
GAIN CALIBRATION
The gain for each ECG channel can be adjusted to correct for
gain mismatches between channels. Factory trimmed gain
correction coefficients are stored in nonvolatile memory
on-chip for GAIN 0, GAIN 1, and GAIN 2; there is no factory
calibration for GAIN 3. The default gain values can be
overwritten by user gain correction coefficients, which are
stored in volatile memory and available by addressing the
appropriate gain control registers (see Table 51). The gain
calibration applies to the ECG data available on the standard
interface and applies to all data rates.
Detecting if the right-leg electrode has fallen off is necessarily
different as RLD_OUT is a low impedance amplifier output. A
pair of fixed threshold comparators monitor the output voltage
to detect amplifier saturation that would indicate a lead-off
condition. This information is available in the DCLEAD-OFF
register (Register 0x1E) along with the lead-off status of all the
input pins.
The propagation delay for detecting a dc lead-off event depends
on the cable capacitance and the programmed current. It is
approximately
LEAD-OFF DETECTION
An ECG system must be able to detect if an electrode is no
longer connected to the patient. The ADAS1000/ADAS1000-1/
ADAS1000-2 support two methods of lead-off detection, ac
lead-off detection and dc lead-off detection. The two systems
are independent and can be used singly or together under the
control of the serial interface (see Table 29).
Delay = Voltage × Cable Capacitance/Programmed Current
For example:
Delay = 1.2 V × (200 pF/70 nA) = 3.43 ms
DC Lead-Off and High Gains
Using dc lead-off at high gains can result in failure of the circuit
to flag a lead-off condition. The chopping nature of the input
amplifier stage contributes to this situation. When the electrode
is off, the electrode is pulled up; however, in this gain setting,
the first stage amplifier goes into saturation before the input
signal crosses the DCLO upper threshold, resulting in no lead-
off flag. This affects the gain setting GAIN 3 (4.2) and partially
GAIN 2 (2.8).
A lead-off event sets a flag in the frame header word (see Table 54).
Identification of which electrode is off is available as part of the
data frame or as a register read from the lead-off status register
(Register LOFF, see Table 47). In the case of ac lead-off, infor-
mation about the amplitude of the lead-off signal or signals can
be read back through the serial interface (see Table 52).
Rev. B | Page 37 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Increasing the AVDD voltage raises the voltage at which the input
amplifiers saturate, allowing the off electrode voltage to rise high
enough to trip the DCLO comparator (fixed upper threshold of
2.4 V). The ADAS1000 operates over a voltage range of 3.15 V
to 5.5 V. If using GAIN 2/GAIN 3 and dc lead-off, an increased
AVDD supply voltage (minimum 3.6 V) allows dc lead-off to
flag correctly at higher gains.
This gives simple dynamic thresholding that automatically
compensates for many of the circuit variables.
The lower threshold is added for cases where the only ac lead-off
is in use and for situations where an electrode cable has been off
for a long time. In this case, the dc voltage has saturated to a rail,
or the electrode cable has somehow shorted to a supply. In either
case, there is no ac signal present, yet the electrode may not be
connected. The lower threshold checks for a minimum signal level.
AC Lead-Off Detection
The alternative method of sensing if the electrodes are connected
to the patient is based on injecting ac currents into each channel
and measuring the amplitudes of the resulting voltages. The
system uses a fixed carrier frequency at 2.039 kHz, which is
high enough to be removed by the ADAS1000/ADAS1000-1/
ADAS1000-2 on-chip digital filters without introducing phase
or amplitude artifacts into the ECG signal.
In addition to the lead-off flag, the user can also read back the
resulting voltage measurement available on a per channel basis.
The measured amplitude for each of the individual electrodes is
available in Register 0x31 through Register 0x35 (LOAMxx
registers, see Table 52).
The propagation delay for detecting an ac lead-off event is <10 ms.
Note that the ac lead-off function is disabled when the
calibration DAC is enabled.
AC LO
DAC
ADC Out of Range
When multiple leads are off, the input amplifiers may run into
saturation. This results in the ADC outputting out of range data
with no carrier to the leads off algorithm. The ac lead-off algorithm
then reports little or no ac amplitude. The ADAS1000 contains
flags to indicate if the ADC data is out of range, indicating a hard
electrode off state. There are programmable overrange and under-
range thresholds that can be seen in the LOFFUTH and LOFFLTH
registers (see Table 39 and Table 40, respectively). The ADC out
of range flag is contained in the header word (see Table 54).
2.039kHz
12.5nA TO
100nA rms
11kΩ
11kΩ
11kΩ
11kΩ
11kΩ
11kΩ
LA
LL
RA
V1
V2
CM
Figure 68. Simplified AC Lead-Off Configuration
The amplitude of the signal is nominally 2 V p-p and is centered
on 1.3 V relative to the chip AGND level. It is ac-coupled into each
electrode. The polarity of the ac lead-off signal can be configured
on a per-electrode basis through Bits[23:18] of the LOFFCTL
register (see Table 29). All electrodes can be driven in phase, and
some can be driven with reversed polarity to minimize the total
injected ac current. Drive amplitude is also programmable. AC
lead-off detection functions only on the input pins (LA, LL, RA,
V1, V2, and CM_IN) and is not supported for the RLD_OUT pin.
SHIELD DRIVER
The shield drive amplifier is a unity gain amplifier. Its purpose
is to drive the shield of the ECG cables. For power consumption
purposes, it can be disabled if not in use. Note that the SHIELD
pin is shared with the respiration pin function, where it can be
muxed to be one of the pins for external capacitor connection.
If the pin is being used for the respiration feature, the shield
function is not available. In this case, if the application requires
a shield drive, an external amplifier connected to the CM_OUT
pin can be used.
The resulting analog input signal applied to the ECG channels is
I/Q demodulated and amplitude detected. The resulting amplitude
is low pass filtered and sent to the digital threshold detectors.
AC lead-off detection offers user programmable dedicated
upper and lower threshold voltages (see Table 39 and Table 40).
Note that these programmed thresholds voltage vary with the
ECG channel gain. The threshold voltages are not affected by
the current level that is programmed. All active channels use
the same detection thresholds.
RESPIRATION (ADAS1000 MODEL ONLY)
The respiration measurement is performed by driving a high
frequency (programmable from 46.5 kHz to 64 kHz) differential
current into two electrodes; the resulting impedance variation
caused by breathing causes the differential voltage to vary at the
respiration rate. The signal is ac-coupled onto the patient. The
acquired signal is AM, with a carrier at the driving frequency
and a shallow modulation envelope at the respiration frequency.
The modulation depth is greatly reduced by the resistance of the
customer-supplied RFI and ESIS protection filters, in addition
to the impedance of the cable and the electrode to skin interface
(see Table 12). The goal is to measure small ohm variation to sub
ohm resolution in the presence of large series resistance. The
circuit itself consists of a respiration DAC that drives the ac-
coupled current at a programmable frequency onto the chosen
pair of electrodes. The resulting variation in voltage is amplified,
A properly connected electrode has a very small signal as the
drive current flows into the right leg (RL), whereas a disconnected
electrode has a larger signal as determined by a capacitive
voltage divider (source and cable capacitance).
If the signal measured is larger than the upper threshold, then
the impedance is high, so a wire is probably off. Selecting the
appropriate threshold setting depends on the particular cable/
electrode/protection scheme, as these parameters are typically
unique for the specific use case. This can take the form of starting
with a high threshold and ratcheting it down until a lead-off is
detected, then increasing the threshold by some safety margin.
Rev. B | Page 38 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
filtered, and synchronously demodulated in the digital domain;
the result is a digital signal that represents the total thoracic or
respiration impedance, including cable and electrode contri-
butions. While it is heavily low-pass filtered on-chip, the user is
required to further process it to extract the envelope and perform
the peak detection needed to establish breathing (or lack thereof).
Internal Respiration Capacitors
The internal respiration function uses an internal RC network
(5 kΩ/100 pF), and this circuit is capable of 200 mΩ resolution
(with up to 5 kΩ total path and cable impedance). The current
is ac-coupled onto the same pins that the measurement is sensed
back on. Figure 69 shows the measurement on Lead I, but,
similarly, the measurement can be configured to measure on
either Lead II or Lead III. The internal capacitor mode requires
no external capacitors and produces currents of ~64 µA p-p
amplitude when configured for maximum amplitude setting
( 1V) through the RESPCTRL register (see Table 30).
Respiration measurement is available on one of the leads (Lead I,
Lead II, or Lead III) or on an external path via a pair of dedicated
pins (EXT_RESP_LA, EXT_RESP_RA, or EXT_RESP_LL).
Only one lead measurement can be made at one time. The
respiration measurement path is not suited for use as additional
ECG measurements because the internal configuration and
demodulation do not align with an ECG measurement; however,
the EXT_RESP_LA, EXT_RESP_RA, or EXT_RESP_LL paths
can be multiplexed into one of the ECG ADC paths, if required,
as discussed in the Extend Switch On Respiration Paths section.
External Respiration Path
The EXT_RESP_xx pins are provided for use either with the
ECG electrode cables or, alternatively, with a dedicated external
sensor independent of the ECG electrode path. Additionally, the
EXT_RESP_xx pins are provided so the user can measure the
respiration signal at the patient side of any input filtering on the
front end. In this case, the user must continue to take precautions
to protect the EXT_RESP_xx pins from any signals applied that
are in excess of the operating voltage range (for example, ESIS
or defibrillator signals).
The respiration signal processing path is not reconfigurable for
ECG measurements, as it is specifically designed for the respiration
signal measurement.
Table 12. Maximum Allowable Cable and Thoracic Loading
Cable Resistance
Cable Capacitance
R < 1 kΩ
C < 1200 pF
1 kΩ < R < 2.5 kΩ
2.5 kΩ < R < 5 kΩ
C < 400 pF
C < 200 pF
RTHORACIC < 2 kΩ
±1V
46.5kHz TO
64kHz
RESPIRATION DAC
DRIVE +
ADAS1000
5kΩ
100pF
CABLE AND ELECTRODE
RESPIRATION
MEASURE
IMPEDANCE < 5kΩ
ECG1_LA
EXT_RESP_LA
ECG2_LL
LA CABLE
FILTER
FILTER
FILTER
IN-AMP AND
ANTI-ALIASING
OVERSAMPLED
HPF
LL CABLE
RA CABLE
MAGNITUDE
AND
SAR
ADC
EXT_RESP_LL
ECG3_RA
PHASE
LPF
7Hz
fc=150kHz fc=10kHz
EXT_RESP_RA
100pF
5kΩ
RESPIRATION DAC
DRIVE–
46.5kHz TO
64kHz
±1V
Figure 69. Simplified Respiration Block Diagram
Rev. B | Page 39 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
External Respiration Capacitors
only one lead (at one time); therefore, only one pair of external
respiration paths (and external capacitors) is required.
If necessary, the ADAS1000 allows the user to connect external
capacitors into the respiration circuit to achieve higher resolution
(<200 mΩ). This level of resolution requires that the cable
impedance be ≤1 kΩ. The diagram in Figure 70 shows the
connections at RESPDAC_xx paths for the extended respiration
configuration. Again, the EXT_RESP_xx paths can be connected
at the patient side of any filtering circuit; however, the user must
provide protection for these pins. While this external capacitor
mode requires external components, it can deliver a larger signal-
to-noise ratio. Note again that respiration can be measured on
If required, further improvements in respiration performance
may be possible with the use of an instrumentation amplifier
and op amp external to the ADAS1000. The instrumentation
amplifier must have sufficiently low noise performance to meet
the target performance levels. This mode uses the external
capacitor mode configuration and is shown in Figure 71. Bit 14
of the RESPCTL register (Address 0x03; see Table 30) allows the
user to bypass the on-chip amplifier when using an external
instrumentation amplifier.
±1V
46.5kHz TO
64kHz
RESPIRATION DAC
DRIVE +
ADAS1000
1nF TO 10nF
1kΩ
RESPDAC_LA
RESPDAC_LL
1kΩ
5kΩ
100pF
MUTUALLY
EXCLUSIVE
CABLE AND ELECTRODE
RESPIRATION
MEASURE
IMPEDANCE < 1kΩ
ECG1_LA
EXT_RESP_LA
ECG2_LL
LA CABLE
LL CABLE
RA CABLE
FILTER
IN-AMP AND
ANTI-ALIASING
OVERSAMPLED
HPF
MAGNITUDE
AND
PHASE
FILTER
FILTER
SAR
ADC
EXT_RESP_LL
ECG3_RA
LPF
7Hz
fc=150kHz fc=10kHz
EXT_RESP_RA
MUTUALLY
EXCLUSIVE
100pF
5kΩ
1nF TO 10nF
1kΩ
RESPDAC_RA
RESPIRATION DAC
DRIVE –
46.5kHz TO
64kHz
±1V
Figure 70. Respiration Measurement Using External Capacitor
50kHz TO
56kHz
ADAS1000
1nF TO 10nF
100Ω
RESPDAC_LA
EXT_RESP_LA
1kΩ
±1V
RESPIRATION DAC
DRIVE + ve
CABLE AND ELECTRODE
RESPIRATION
MEASURE
IMPEDANCE < 1kΩ
LA CABLE
RA CABLE
IN-AMP AND
ANTI-ALIASING
OVERSAMPLED
10kΩ
10kΩ
HPF
MAGNITUDE
AND
PHASE
SAR
ADC
GAIN
LPF
7Hz
fc=150kHz fc=10kHz
EXT_RESP_RA
REFOUT = 1.8V
1/2 OF AD8606
1nF TO 10nF
10kΩ
46.5kHz TO
64kHz
0.9V
100Ω
1kΩ
10kΩ
RESPDAC_RA
±1V
RESPIRATION DAC
DRIVE – ve
1/2 OF AD8606
Figure 71. Respiration Using External Capacitor and External Amplifiers
Rev. B | Page 40 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
Respiration Carrier Frequency
EVALUATING RESPIRATION PERFORMANCE
The frequency of the respiration carrier is programmable and
can be varied through the RESPCTL register (Address 0x03, see
Table 30). The status of the HP bit in the ECGCTL register also
has an influence on the carrier frequency as shown in Table 13.
ECG simulators offer a convenient means of studying the
performance of the ADAS1000. While many simulators offer a
variable-resistance respiration capability, care must be taken
when using this feature.
Some simulators use electrically programmable resistors, often
referred to as digiPOTs, to create the time-varying resistance to
be measured by the respiration function. The capacitances at the
terminals of the digiPOT are often unequal and code-dependent,
and these unbalanced capacitances can give rise to unexpectedly
large or small results on different leads for the same programmed
resistance variation. Best results are obtained with a purpose-
built fixture that carefully balances the capacitance presented to
each ECG electrode.
Table 13. Control of Respiration Carrier Frequencies.
Respiration
RESP- Carrier
RESPALTFREQ1 RESPEXTSYNC1
HP2 FREQ1 Frequency
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
00
01
10
11
00
01
10
11
00
01
10
11
00
01
10
11
56
54
52
50
56
54
52
50
EXTEND SWITCH ON RESPIRATION PATHS
There is additional multiplexing on the external respiration inputs
to allow them to serve as additional electrode inputs to the existing
five ECG ADC channels. This approach allows a user to configure
eight electrode inputs; however, it is not intended as a true
8-channel/12-lead solution. Time overheads are required to
reconfigure the multiplexer arrangement using the serial interface
in addition to filter the latency as described in Table 16.
64
56.9
51.2
46.5
32
28
25.5
23
The user has full control over the SW1/SW2/SW3 configuration
as outlined in Table 50.
SW1a
1 Control bits from RESPCTL (Register 0x03).
2 Control bit from ECGCTL (Register 0x01).
TO ECG1_LA CHANNEL
SW2a
SW3a
In applications where an external signal generator is used to
develop a respiration carrier signal, that external signal source
can be synchronized to the internal carrier using the signal
available on GPIO3 when Bit 7, RESPEXTSEL, is enabled in
the respiration control register (see Table 30).
SW1b
TO ECG2_LL CHANNEL
SW2b
SW3b
SW1c
TO ECG3_RA CHANNEL
SW2c
SW3c
Table 14. Control of Respiration Carrier Frequency
Available on GPIO3
SW1d
TO ECG4_V1 CHANNEL
SW2d
SW3d
RESPALT- RESPEXT-
RESP- Respiration Carrier
FREQ1
SYNC1
HP2 FREQ1 Frequency on GPIO3
SW1e
TO ECG5_V2 CHANNEL
SW2e
SW3e
0
1
1
1
1
1
1
1
1
X3
1
1
1
1
1
1
1
1
X3
1
1
1
1
0
0
0
0
XX3
00
01
10
11
00
01
10
11
64
64
56
51.2
46.5
32
28
25.5
23
TO RESPIRATION CIRCUITRY
EXT_RESP_RA
EXT_RESP_LA
EXT_RESP_LL
Figure 72. Alternative Use of the Respiration Paths
1 Control bits from RESPCTL (Register 0x03).
2 Control bit from ECGCTL (Register 0x01).
3 X = don’t care.
Rev. B | Page 41 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
The on-chip filtering contributes some delay to the pace signal
(see the Pace Latency section).
PACING ARTIFACT DETECTION FUNCTION
(ADAS1000 ONLY)
Choice of Leads
The pacing artifact validation function qualifies potential
pacing artifacts and measures the width and amplitude of valid
pulses. These parameters are stored in and available from any of
the pace data registers (Address 0x1A, and Address 0x3A to
Address 0x3C). This function runs in parallel with the ECG
channels. Digital detection is performed using a state machine
operating on the 128 kHz 16-bit data from the ECG decimation
chain. The main ECG signals are further decimated before
appearing in the 2 kHz output stream so that detected pace
signals are not perfectly time-aligned with fully-filtered ECG
data. This time difference is deterministic and can be
compensated for.
Three identical and independent state machines are available
and can be configured to run on up to three of four possible
leads (Lead I, Lead II, Lead III, and aVF) for pacing artifact
detection. Any necessary lead calculations are performed
internally and are independent of ECG channel settings for
output data rate, low-pass filter cutoff, and mode (electrode,
analog lead, common electrode). These calculations take into
account the available front-end configurations as detailed in
Table 15.
The pace detection algorithm searches for pulses by analyzing
samples in the 128 kHz ECG data stream. The algorithm
searches for a leading edge, a peak, and a trailing edge as
defined by values in the PACEEDGETH, PACEAMPTH, and
PACELVLTH registers, along with fixed width qualifiers. The
post-reset default register values can be overwritten via the SPI
bus, and different values can be used for each of the three pace
detection state machines.
The pacing artifact validation function can detect and
measure pacing artifacts with widths from 100 μs to 2 ms
and with amplitudes of <400 μV to >1000 mV. Its filters are
designed to reject heartbeat, noise, and minute ventilation
pulses. The flowchart for the pace detection algorithm is
shown in Figure 74.
The ADAS1000 pace algorithm can operate with the ac lead-off
and respiration impedance measurement circuitry enabled.
Some users may not want to use three pace leads for detection.
In this case, Lead II is the vector of choice, because this lead is
likely to display the best pacing artifact. The other two pace
instances can be disabled if not in use.
Once a valid pace is detected in the assigned leads, the pace-
detected flags appear in the header word (see Table 54) at the
start of the packet of ECG words. These bits indicate that a pace
is qualified. Further information on height and width of pace is
available by reading the contents of Address 0x1A (PACEDATA
register, see Table 44). This word can be included in the ECG
data packet/frame as dictated by the frame control register (see
Table 37). The data available in the PACEDATA register is
limited to seven bits total for width and height information;
therefore, if more resolution is required on the pace height
and width, this is available by issuing read commands of the
PACExDATA registers (Address 0x3A to Address 0x3C) as
shown in Table 53.
The first step in pace detection is to search the data stream for a
valid leading edge. Once a candidate edge is detected, the algorithm
begins searching for a second, opposite-polarity edge that meets
with pulse width criteria and passes the (optional) noise filters.
Only those pulses meeting all the criteria are flagged as valid
pace pulses. Detection of a valid pace pulse sets the flag or flags
in the frame header register and stores amplitude and width
information in the PACEDATA register (Address 0x1A; see
Table 44). The pace algorithm looks for a negative or positive pulse.
Table 15. Pace Lead Calculation
0x04 [8:3]3
00
01
10
11
Lead I
(LA − RA)
Lead II
(LL − RA)
Lead III
(LL − LA)
aVF
0x01 [10]1 0x05 [8]2 Configuration
(Lead II + Lead III)/2
0
0
1
0
1
X
Digital leads
LA – RA
LL – RA
LL – LA
LL − (LA + RA)/2
CH2 − (CH1 + CH3)/2
CH1 − CH3 CH2 − CH3 CH2 − CH1
Common
Lead I
Lead II
CH2
Lead II – Lead I
CH2 − CH1
Lead II − 0.5 × Lead I
CH2 − 0.5 × CH1
electrode lead A CH1
Analog leads
Lead I
CH1
Lead II
−CH3
Lead III
CH2
Lead II − 0.5 × Lead I − CH3 − 0.5 × CH1
1 Register ECGCTL, Bit CHCONFIG, see Table 28.
2 Register CMREFCTL, Bit CEREFEN, see Table 32.
3 Register PACECTL, Bit PACExSEL [1:0], see Table 31.
Rev. B | Page 42 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
START
Detection Algorithm Overview
The pace pulse amplitude and width varies over a wide range,
while its shape is affected by both the internal filtering arising
from the decimation process and the low pass nature of the
electrodes, cabling, and components used for defibrillation and
ESIS protection. The ADAS1000 provides user programmable
variables to optimize the performance of the algorithm within
the ECG system, given all these limiting elements. The default
parameter values are probably not optimal for any particular
system design; experimentation and evaluation are needed to
ensure robust performance.
ENABLE PACE DETECTION
SELECT LEADS
START PACE DETECTION
ALGORITHM
FIND
LEADING EDGE
NO
A > PACEEDGETH?
YES
START PULSE
WIDTH TIMER
PACE
PULSE
FIND
END OF
NO
LEADING EDGE
B < PACELVL
PACELVLTH
YES
START NOISE
FILTERS (if enabled)
LEADING EDGE
YES
LEADING EDGE STOP
PACEAMPTH
TRAILING
EDGE
DETECTED?
NO
NO
PACEEDGETH
YES
PACE WIDTH
PACE AMPLITUDE
> PACEAMPTH
RECHARGE
PULSE
YES
Figure 73. Typical Pace Signal
NO
NO
NOISE FILTER
PASSED?
The first step in pace detection is to search the data stream for a
valid leading edge. Once a candidate edge is detected, the algorithm
verifies that the signal looks like a pulse and then begins searching
for a second, opposite polarity edge that meets the pulse width
and amplitude criteria and passes the optional noise filters. Only
the pulses meeting all requirements are flagged as valid pace pulses.
Detection of a valid pace pulse sets the flag or flags in the frame
header register and stores amplitude and width information in
the PACEDATA register (Address 0x1A; see Table 34).
YES
PULSE WIDTH
> 100µs AND <2ms
YES
FLAG PACE DETECTED
UPDATE REGISTERS WITH
WIDTH AND HEIGHT
The pace algorithm detects pulses of both negative and positive
polarity using a single set of parameters by tracking the slope of
the leading edge and making the necessary adjustments to internal
parameter signs. This frees the user to concentrate on determining
appropriate threshold values based on pulse shape without
concern for pulse polarity.
Figure 74. Overview of Pace Algorithm
The three user controlled parameters for the pace detection
algorithm are Pace Amplitude Threshold (PACEAMPTH), Pace
Level Threshold (PACELVLTH), and Pace Edge Threshold
(PACEEDGETH).
Rev. B | Page 43 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Pace Edge Threshold
Pace Amplitude Threshold
This programmable level (Address 0x0E, see Table 41) is used to
find a leading edge, signifying the start of a potential pace pulse. A
candidate edge is one in which the leading edge crosses a threshold
PACEEDGETH from the recent baseline. PACEEDGETH can
be assigned any value between 0 and 255. Setting PACEEDGETH
to 0 forces it to the value PACEAMPTH/2 (see equation).
Non-zero values give the following:
This register (Address 0x07, see Table 34) sets the minimum
valid pace pulse amplitude. PACEAMPTH is an unsigned 8-bit
number. The programmed height is given by:
2×N ×VREF
PACEAMPTH setting =
,
GAIN ×216
where:
N is the 8-bit programmed PACEAMPTH value (1 ≤ N ≤ 255).
VREF is the ADAS1000 reference voltage of 1.8 V.
GAIN is the programmed gain of the ECG channel.
N ×VREF
PACEEDGETH setting =
GAIN ×216
where:
The minimum threshold for ×1.4 gain is 19.6 µV, while the
maximum for the same gain setting is 5.00 m V. PACEAMPTH
is typically set to the minimum expected pace amplitude and
must be larger than the value of PACEEDGETH.
N is the 8-bit programmed PACEEDGETH value (1 ≤ N ≤ 255).
VREF is the ADAS1000 reference voltage of 1.8 V.
GAIN is the programmed gain of the ECG channel.
The minimum threshold for ×1.4 gain is 19.6 µV, while the
maximum for the same gain setting is 5.00 m V.
The default register setting of N = 0x24 results in 706 μV for a
gain = 1 setting. An initial PACEAMPTH setting between
700 µV and 1 mV provides a good starting point for both
unipolar and biventricular pacing detection. Values below
250 µV are not recommended because they greatly increase
sensitivity to ambient noise from the patient. The amplitude
may need to be adjusted much higher than 1 mV when other
medical devices are connected to the patient.
Pace Level Threshold
This programmable level (Address 0x0F, see Table 42) is used to
detect when the leading edge of a candidate pulse ends. In general,
a pace pulse is not perfectly square, and the top, meaning the
portion after the leading edge, may continue to increase slightly
or droop back towards the baseline. PACELVLTH defines an
allowable slope for this portion of the candidate pulse, where
the slope is defined as the change in value over an internally-
fixed interval after the pace edge is qualified.
Pace Validation Filters
A candidate pulse that successfully passes the combined tests of
PACEEDGETH, PACELVLTH, and PACEAMPTH is next passed
through two optional validation filters. These filters are used to
reject sub-threshold pulses such as minute ventilation (MV) pulse
and signals from inductively coupled implantable telemetry
systems. These filters perform different tests of pulse shape
using a number of samples. Both filters are enabled by default;
Filter 1 is controlled by Bit 9 in the PACECTL register (see
Table 31) and Filter 2 is controlled by Bit 10 in the same register.
These filters are not available on a lead by lead basis; if enabled,
they are applied to all leads being used for pace detection.
PACELVLTH is an 8-bit, twos complement number. Positive
values represent movement away from the baseline (pulse
amplitude is still increasing) while negative values represent
droop back towards the baseline.
N ×VREF
PACELVLTH setting =
GAIN ×216
where:
N is the 8-bit programmed PACELVLTH value (−128 ≤ N ≤ 127).
VREF is the ADAS1000 reference voltage of 1.8 V.
GAIN is the programmed gain of the ECG channel.
Pace Width Filter
A candidate pulse that successfully passes the edge, amplitude, and
noise filters is finally checked for width. When this final filter is
enabled, it checks that the candidate pulse is between 100 μs
and 2 ms wide. When a valid pace width is detected, the width
is stored. Disabling this filter affects only the minimum width
(100 µs) determination; the maximum width detection portion
of the filter is always active. This filter is controlled by the
PACECTL register, Bit 11 (see Table 31).
The minimum value for ×1.4 gain is 9.8 µV, while the maximum
for the same gain setting is 2.50 m V.
An additional qualification step, performed after PACELVLTH
is satisfied, rejects pulses with a leading edge transition time greater
than about 156 µs. This filter improves immunity to motion and
other artifacts and cannot be disabled. Overly aggressive ESIS
filtering causes this filter to disqualify valid pace pulses. In such
cases, increasing the value of PACEEDGETH provides more
robust pace pulse detection. Although counterintuitive, this
change forces a larger initial deviation from the recent baseline
before the pace detection algorithm starts, reducing the time
until PACELVLTH comes into play and shortening the apparent
leading edge transition. Increasing the value of PACEEDGETH
may require a reduction in PACEAMPTH.
Rev. B | Page 44 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
BIVENTRICULAR PACERS
PACE WIDTH
As described previously, the pace algorithm expects the pace pulse
to be less than 2 ms wide. In a pacer where both ventricles are
paced, they can be paced simultaneously. Where they fall within
the width and height limits programmed into the algorithm, a
valid pace is flagged, but only one pace pulse may be visible.
The ADAS1000 is capable of measuring pace widths of 100 μs
to 2.00 ms. The measured pace width is available through the
PACExDATA registers. These registers have limited resolution.
The minimum pace width is 101.56 μs and the maximum is
2.00 ms. The pace detection algorithm always returns a width
greater than what is measured at the 50% point, ensuring that
the algorithm is capable of measuring a narrow 100 μs pulse. A
valid pulse width of 100 μs is reported as 101.56 μs. Any valid
pace pulses ≥ 2.00 ms and ≤ 2.25 ms are reported as 2.00 ms.
With the pace width filter enabled, the pace algorithm seeks
pace pulse widths within a 100 μs to 2 ms window. Assuming
that this filter is enabled and in a scenario where two ventricle
pacer pulses fire at slightly different times, resulting in the pulse
showing in the lead as one large, wider pulse, a valid pace is
flagged so long as the total width does not exceed 2 ms.
PACE LATENCY
The pace algorithm always examines 128 kHz, 16-bit ECG data,
regardless of the selected frame rate and ECG filter setting. A
pace pulse is qualified when a valid trailing edge is detected and
is flagged in the next available frame header. Pace and ECG data
is always correctly time-aligned at the 128 kHz frame rate, but
the additional filtering inherent in the slower frame rates delays
the ECG data of the frame relative to the pace pulse flag. These
delays are summarized in Table 16 and must be taken into account
to enable correct positioning of the pace event relative to the
ECG data.
PACE DETECTION MEASUREMENTS
Design verification of the ADAS1000 digital pace algorithm
includes detection of a range of simulated pace signals in
addition to using the ADAS1000 and evaluation board with
one pacemaker device connected to various simulated loads
(approximately 200 Ω to over 2 kΩ) and covering the following
4 waveform corners.
•
Minimum pulse width (100 μs), minimum height (to
<300 μV)
There is an inherent one-frame-period uncertainty in the exact
location of the pace trailing edge.
•
Minimum pulse width (100 μs), maximum height (up to
1.0 V)
PACE DETECTION VIA SECONDARY SERIAL
INTERFACE (ADAS1000 AND ADAS1000-1 ONLY)
•
•
Maximum pulse width (2 ms), minimum height (to <300 μV)
Maximum pulse width (2 ms), maximum height (up to 1.0 V)
The ADAS1000/ADAS1000-1 provide a second serial interface
for users who want to implement their own pace detection
schemes. This interface is configured as a master interface. It
provides ECG data at the 128 kHz data rate only. The purpose
of this interface is to allow the user to access the ECG data at a
rate sufficient to allow them to run their own pace algorithm,
while maintaining all the filtering and decimation of the ECG
data that the ADAS1000/ADAS1000-1 offer on the standard
serial interface (2 kHz and 16 kHz data rates). This dedicated
pace interface uses three of the four GPIO pins, leaving one
GPIO pin available even when the secondary serial interface
is enabled. Note that the on-chip digital calibration to ensure
channel gain matching does not apply to data that is available
on this interface. This interface is discussed in more detail in
the Secondary Serial Interface section.
These scenarios passed with acceptable results. The use of the
ac lead-off function had no obvious impact on the recorded
pace height, width, or the ability of the pace detection algorithm
to identify a pace pulse. The pace algorithm was also evaluated
with the respiration carrier enabled; again, no differences in the
threshold or pacer detect were noted from the carrier.
While these experiments validate the pace algorithm over a
confined set of circumstances and conditions, they do not
replace end system verification of the pacer algorithm. This
can be performed in only the end system, using the system
manufacturer’s specified cables and validation data set.
EVALUATING PACE DETECTION PERFORMANCE
ECG simulators offer a convenient means of studying the perfor-
mance and ability of the ADAS1000 to capture pace signals over
the range of widths and heights defined by the various regulatory
standards. While the pace detection algorithm of the ADAS1000
is designed to conform to medical instrument standards (pace
widths of 100 μs to 2.00 ms and with amplitudes of <400 μV to
>1000 mV), some simulators put out signals wider or narrower
than called for in the standards. The pace detection algorithm
has been designed to measure a maximum pace widths of 2 ms
with a margin of 0.25 ms to allow for simulator variations.
Rev. B | Page 45 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
The amount of decimation depends on the selected data rate,
with more decimation for the lower data rates.
FILTERING
Figure 75 shows the ECG digital signal processing. The ADC
sample rate is programmable. In high performance mode, it
is 2.048 MHz; in low power mode, the sampling rate is reduced
to 1.024 MHz. The user can tap off framing data at one of three
data rates, 128 kHz, 16 kHz, or 2 kHz. Note that although the
data-word width is 24 bits for the 2 kHz and 16 kHz data rate,
the usable bits are 19 and 18, respectively.
Four selectable low-pass filter corners are available at the 2 kHz
data rate.
Filters are cleared by a reset. Table 16 shows the filter latencies
at the different data rates.
AC LEAD-OFF
DETECTION
2.048MHz
ADC DATA
PACE
14-BITS
128kHz
–3dB AT 13kHz
DETECTION
2.048MHz
AVAILABLE DATA RATE
CHOICE OF 1:
128kHz DATA RATE
16-BITS WIDE
ACLO
CARRIER
NOTCH
2kHz
128kHz
16kHz DATA RATE
24-BITS WIDE
18 USABLE BITS
16kHz
–3dB AT 3.5kHz
16kHz
2kHz DATA RATE
24-BITS WIDE
2kHz
–3dB AT 450Hz
19 USABLE BITS
40Hz
150Hz
CALIBRATION
31.25Hz DATA RATE
24-BITS WIDE
250Hz
(PROGRAMMABLE BESSEL )
~22 USABLE BITS
~7Hz
Figure 75. ECG Channel Filter Signal Flow
Table 16. Relationship of ECG Waveform to Pace Indication1, 2, 3
Data Rate
Conditions
Apparent Delay of ECG Data Relative to Pace Event4
2 kHz
450 Hz ECG bandwidth
250 Hz ECG bandwidth
150 Hz ECG bandwidth
40 Hz ECG bandwidth
0.984 ms
1.915 ms
2.695 ms
7.641 ms
109 μs
16 kHz
128 kHz
0
1 ECG waveform delay is the time required to reach 50% of final value following a step input.
2 Guaranteed by design, not subject to production test.
3 There is an unavoidable residual uncertainty of 8 μs in determining the pace pulse trailing edge.
4 Add 38 μs to obtain the absolute delay for any setting.
Rev. B | Page 46 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
When a device is configured as a slave (ADAS1000-2), the
SYNC_GANG and CLK_IO pins are set as inputs.
VOLTAGE REFERENCE
The ADAS1000/ADAS1000-1/ADAS1000-2 have a high
performance, low noise, on-chip 1.8 V reference for use in
the ADC and DAC circuits. The REFOUT of one device is
intended to drive the REFIN of the same device. The internal
reference is not intended to drive significant external current;
for optimum performance in gang operation with multiple
devices, each device should use its own internal reference.
Synchronizing Devices
The ganged devices need to share a common clock to ensure
that conversions are synchronized. One approach is to drive
the slave CLK_IO pins from the master CLK_IO pin. Alter-
natively, an external 8.192 MHz clock can be used to drive
the CLK_IO pins of all devices. The CLK_IO powers up high
impedance until configured in gang mode.
An external 1.8 V reference can be used to provide the
required VREF. In such cases, there is an internal buffer pro-
vided for use with external reference. The REFIN pin is a
dynamic load with an average input current of approximately
100 μA per enabled channel, including respiration. When
the internal reference is used, the REFOUT pin requires
decoupling with a10 μF capacitor with low ESR (0.2 Ω
maximum) in parallel with 0.01 μF capacitor to REFGND,
these capacitors should be placed as close to the device pins
as possible and on the same side of the PCB as the device.
In addition, the SYNC_GANG pin is used to synchronize
the start of the ADC conversion across multiple devices. The
SYNC_GANG pin is automatically driven by the master and
is an input to all the slaves. SYNC_GANG is in high
impedance until enabled via gang mode.
When connecting devices in gang mode, the SYNC_GANG
output is triggered once when the master device starts to convert.
Therefore, to ensure that the slave device or devices receive this
synchronization signal, configure the slave device first for oper-
ation and enable conversions, followed by issuing the conversion
signal to the ECGCTL register in the master device.
GANG MODE OPERATION
While a single ADAS1000 or ADAS1000-1 provides the ECG
channels to support a five-electrode and one-RLD electrode
(or up to 8-lead) system, the device has also been designed so
that it can easily extend to larger systems by paralleling up
multiple devices. In this mode of operation, an ADAS1000 or
ADAS1000-1 master device can easily be operated with one
or more ADAS1000-2 slave devices. In such a configuration,
one of the devices (ADAS1000 or ADAS1000-1) is designated
as master, and any others are designated as slaves. It is
MASTER
SLAVE 0
CLK_OI
CLK_IO
SYNC_GANG
CM_OUT
SYNC_GANG
CM_IN
CAL_DAC_IO
CAL_DAC_IO
SLAVE 1
important that the multiple devices operate well together;
with this in mind, the pertinent inputs/outputs to interface
between master and slave devices have been made available.
CLK_IO
SYNC_GANG
CM_IN
CAL_DAC_IO
Note that when using multiple devices, the user must collect
the ECG data directly from each device. If using a traditional
12-lead arrangement where the Vx leads are measured relative to
WCT, the user must configure the ADAS1000 or ADAS1000-1
master device in lead mode with the slave ADAS1000-2
device configured for electrode mode. The LSB size for
electrode and lead data differs (see Table 43 for details).
Figure 76. Master/Slave Connections in Gang Mode, Using Multiple
ADAS1000/ADAS1000-1/ADAS1000-2 Devices
Calibration
The calibration DAC signal from one device (master) can be
output on the CAL_DAC_IO pin and used as the calibration
input for other devices (slaves) when used in the gang mode
of operation. This ensures that they are all being calibrated
using the same signal which results in better matching across
channels. This does not happen automatically in gang mode
but, rather, must be configured via Table 36.
In gang mode, all devices must be operated in the same
power mode (either high performance or low power) and
the same data rate.
Master/Slave
The ADAS1000 or ADAS1000-1 can be configured as a
master or slave, while the ADAS1000-2 can only be config-
ured as a slave. A device is selected as a master or slave using
Bit 5, master, in the ECGCTL register (see Table 28). Gang
mode is enabled by setting Bit 4, gang, in the same register.
When a device is configured as a master, the SYNC_GANG
pin is automatically set as an output.
Rev. B | Page 47 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Common Mode
Right Leg Drive
The ADAS1000/ADAS1000-1 have a dedicated CM_OUT pin
serving as an output and a CM_IN pin as an input. In gang
mode, the master device determines the common-mode voltage
based on the selected input electrodes. This common-mode
signal (on CM_OUT) can then be used by subsequent slave
devices (applied to CM_IN) as the common-mode reference.
All electrodes within the slave device are then measured with
respect to the CM_IN signal from the master device. See the
CMREFCTL register in Table 32 for more details on the control
via the serial interface. Figure 77 shows the connections
between a master and slave device using multiple
The right leg drive comes from the master device. If the internal
RLD resistors of the slave device are to contribute to the RLD
loop, tie the RLD_SJ pins of master and slave together.
Sequencing Devices into Gang Mode
When entering gang mode with multiple devices, both
devices can be configured for operation, but the conversion
enable bit (ECGCTL register, Bit 2, Table 28) of the master
device should be set after the conversion enable bit of the
slave device. When the master device conversion signal is set,
the master device generates one edge on its SYNC_GANG
pin. This applies to any slave SYNC_GANG inputs, allowing
the devices to synchronize ADC conversions.
ADAS1000/ADAS1000-2 devices.
CM_IN
RLD_OUT
CM_OUT/
WCT
REFOUT
VREF
SHIELD
AVDD
IOVDD
REFIN
CAL_DAC_IO
DRIVEN
LEAD AMP
ADCVDD
(optional)
ADCVDD, DVDD
1.8V
REGULATORS
CALIBRATION
DAC
SHIELD
DRIVE
AMP
DVDD
(optional)
VCM_REF
(1.3V)
RESPIRATION
DAC
ADAS1000
COMMON-
MODE AMP
AC
LEAD-OFF
DAC
LEAD-OFF
DETECTION
10kΩ
PACE
DETECTION
CS
MUXES
SCLK
SDI
SDO
DRDY
SYNC_GANG
5 × ECG PATH
AMP
TAKE LEAD
DATA
ELECTRODES
FILTERS,
CONTROL,
AND
INTERFACE
LOGIC
×5
ADC
EXT RESP_LA
EXT RESP LL
EXT RESP_RA
AMP
ADC
CLK_IO
CLOCK GEN/OSC/
EXTERNAL CLK
SOURCE
RESPIRATION PATH
XTAL1 XTAL2
AVDD
IOVDD
REFIN
REFOUT
VREF
CAL_DAC_IN
RLD_SJ
CM_IN
ADCVDD
(optional)
ADCVDD, DVDD
1.8V
REGULATORS
DVDD
(optional)
VCM_REF
(1.3V)
ADAS1000-2
SLAVE
AC
COMMON-
MODE AMP
LEAD-OFF
DAC
LEAD-OFF
DETECTION
PACE
DETECTION
CS
MUXES
SCLK
SDI
SDO
DRDY
SYNC_GANG
5 × ECG PATH
AMP
TAKE
ELECTRODE
DATA
FILTERS,
CONTROL,
AND
INTERFACE
LOGIC
ELECTRODES
×5
ADC
CLK_IO
CLOCK GEN/OSC/
EXTERNAL CLK
SOURCE
Figure 77. Configuring Multiple Devices to Extend Number of Electrodes/Leads
(This Example Uses ADAS1000 as Master and ADAS1000-2 as Slave. Similarly the ADAS1000-1 Could be Used as Master.)
Rev. B | Page 48 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
have the relevant synchronized data. Alternative methods might
use individual controllers for each device or separate SDO
paths.
INTERFACING IN GANG MODE
As shown in Figure 77, when using multiple devices, the
user must collect the ECG data directly from each device.
The example shown in Figure 78 illustrates one possibility
of how to approach interfacing to a master and slave device.
For some applications, digital isolation is required between
the host and the ADAS1000. The example shown illustrates a
means to ensure that the number of lines requiring isolation
is minimized.
Note that SCLK, SDO, and SDI are shared here with
CS
individual
lines. This requires the user to read the data on
both devices twice as fast to ensure that they can capture all
the data to maintain the chosen data rate and ensure they
Table 17. Some Possible Arrangements for Gang Operation
Master
Slave 1
Slave 2
Features
Number of Electrodes
10 ECG, CM_IN, RLD
15 ECG, CM_IN, RLD
8 ECG, CM_IN, RLD
10 ECG, CM_IN, RLD
8 ECG, CM_IN, RLD
8 ECG, CM_IN, RLD
Number of Leads
ADAS1000
ADAS1000
ADAS1000
ADAS1000-1
ADAS1000-3
ADAS1000-4
ADAS1000-2
ADAS1000-2
ADAS1000-3
ADAS1000-2
ADAS1000-2
ADAS1000-2
ECG, respiration, pace
ECG, respiration, pace
ECG, respiration, pace
ECG
12-lead + spare ADC channel
15-lead + 3 spare ADC channels
12-lead (derived leads)
12-lead + spare ADC channel
12-lead (derived leads)
ADAS1000-2
ECG
ECG, respiration, pace
12-lead (derived leads)
SCLK
SDI
MICROCRONTROLLER/
DSP
CS1
CS2
SDO
MASTER
SCLK
SLAVE
SCLK
SDI
SDI
CS
CS
DRDY (OPTIONAL)
DRDY (OPTIONAL)
SDO
SDO
Figure 78. One Method of Interfacing to Multiple Devices
Rev. B | Page 49 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
SERIAL INTERFACES
The ADAS1000/ADAS1000-1/ADAS1000-2 are controlled via
a standard serial interface allowing configuration of registers
and readback of ECG data. This is an SPI-compatible interface
that can operate at SCLK frequencies up to 40 MHz.
MICROCONTROLLER/
DSP
ADAS1000
SCLK
CS
SCLK
CS
MOSI
MISO
GPIO
SDI
SDO
DRDY
The ADAS1000/ADAS1000-1 also provide an optional secondary
serial interface that is capable of providing ECG data at the
128 kHz data rate for users wishing to apply their own digital
pace detection algorithm. This is a master interface that
operates with an SCLK of 20.48 MHz.
Figure 79. Serial Interface
Write Mode
The serial word for a write is 32 bits long, MSB first. The
serial interface works with both a continuous and a burst
(gated) serial clock. The falling edge of
cycle. Serial data applied to SDI is clocked into the ADAS1000/
ADAS1000-1/ADAS1000-2 on rising SCLK edges. At least 32
rising clock edges must be applied to SCLK to clock in 32 bits of
STANDARD SERIAL INTERFACE
CS
starts the write
The standard serial interface is LVTTL-compatible when operating
from a 2.3 V to 3.6 V IOVDD supply. This is the primary interface
for controlling the ADAS1000/ADAS1000-1/ADAS1000-2,
reading and writing registers, and reading frame data containing
all the ECG data-words and other status functions within the
device.
CS
data before
is taken high again. The addressed input register
CS
is updated on the rising edge of . For another serial transfer
CS
to take place, must be taken low again. Register writes are used
The SPI is controlled by the following five pins:
to configure the device. Once the device is configured and enabled
for conversions, frame data can be initiated to start clocking out
ECG data on SDO at the programmed data rate. Normal operation
for the device is to send out frames of ECG data. Typically, register
reads and writes are needed only during start-up configuration.
However, it is possible to write new configuration data to the
device while in framing mode. A new write command is accepted
within the frame and, depending on the nature of the command,
there may be a need to flush out the internal filters (wait periods)
before seeing usable framing data again.
CS
CS
low selects
•
(frame synchronization input). Asserting
CS
the device. When is high, data on the SDI pin is ignored.
CS
If
multiple SPI devices can share a common SDO pin. The
pin can be tied low to reduce the number of isolated paths
CS
is inactive, the SDO output driver is disabled, so that
CS
required. When
is tied low, there is no frame around
the data-words; therefore, the user must be aware of where
they are within the frame. All data-words with 2 kHz and
16 kHz data rates contain register addresses at the start of
each word within the frame. Users can resynchronize the
interface by holding SDI high for 64 SCLK cycles, followed
by a read of any register so that SDI is brought low for the
first bit of the following word.
SDI (serial data input pin): Data on SDI is clocked into the
device on the rising edges of SCLK.
SCLK (clocks data in and out of the device). SCLK should
Write/Read Data Format
Address, data, and the read/write bits are all in the same word.
CS
Data is updated on the rising edge of
or the first cycle of the
following word. For all write commands to the ADAS1000/
ADAS1000-1/ADAS1000-2, the data-word is 32 bits, as shown
in Table 18. Similarly, when using data rates of 2 kHz and
16 kHz, each word is 32 bits (address bits and data bits).
•
•
•
CS
idle high when
SDO (serial data output pin for data readback). Data is
shifted out on SDO on the falling edges of SCLK. The
is high.
Table 18. Serial Bit Assignment (Applies to All Register
Writes, 2 kHz and 16 kHz Reads)
B31
[B30:B24]
[B23:B0]
CS
SDO output driver is high-Z when
is high.
R/W
Address bits[6:0]
Data bits [23:0] (MSB first)
DRDY
•
(data ready, optional). Data ready when low, busy
when high. Indicates the internal status of the ADAS1000/
ADAS1000-1/ADAS1000-2 digital logic. It is driven
high/busy during reset. If data frames are enabled and the
frame buffer is empty, this pin is driven busy/high. If the
frame buffer is full, this pin is driven low/ready. If data frames
are not enabled, this pin is driven low to indicate that the
device is ready to accept register read/write commands.
When reading packet data, the entire packet must be read
For register reads, data is shifted out during the next word, as
shown in Table 19.
Table 19. Write/Read Data Stream
Digital
Pin
Command 1
Command 2
Command 2
SDI
Read Address 1
Read Address 2
Write Address 3
SDO
Address 1
Address 2
Read Data 1
Read Data 2
DRDY
to allow the
return back high. The host controller
must treat the DRDY signal as a level sensitive input.
Rev. B | Page 50 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
In the 128 kHz data rate, all write words are still 32-bit writes
but the read words in the data packet are now 16 bits (upper
16 bits of register). There are no address bits, only data bits.
Register space that is larger than 16 bits spans across 2 ×
16-bit words (for example, pace and respiration).
Read Mode
Although the primary reading function within the ADAS1000/
ADAS1000-1/ADAS1000-2 is the output of the ECG frame
data, the devices also allow reading of all configuration regis-
ters. To read a register, the user must first address the device
with a read command containing the particular register address.
If the device is already in data framing mode, the read register
command can be interleaved between the frames by issuing a
read register command during the last word of frame data. Data
shifted out during the next word is the register read data. To
return to framing mode, the user must re-enable framing by
issuing a read of the frame header register (Address 0x40; see
Table 54). This register write can be used to flush out the
register contents from the previous read command.
Data Frames/Packets
The general data packet structure is shown in Table 18. Data
can be received in two different frame formats. For the 2 kHz
and 16 kHz data rates, a 32-bit data format is used (where the
register address is encapsulated in the upper byte, identifying
the word within the frame) (see Table 22). For the 128 kHz data
rate, words are provided in 16-bit data format (see Table 23).
When the configuration is complete, the user can begin reading
frames by issuing a read command to the frame header register
(see Table 54). The ADAS1000/ADAS1000-1/ADAS1000-2
continue to make frames available until another register address
is written (read or write command). To continue reading frame
data, continue to write all zeros on SDI, which is a write of the
NOP register (Address 0x00). A frame is interrupted only when
another read or write command is issued.
Table 20. Example of Reading Registers and Frames
SDI
….. NOP
Read
Address
N
Read
frames
NOP
NOP
…..
…..
SDO ….. Frame
Frame
CRC
Register
Data N
Frame
header
Frame
data
data
Regular register reads are always 32 bits long and MSB first.
CS
Each frame can be a large amount of data plus status words.
Serial Clock Rate
can toggle between each word of data within a frame, or it can
be held constantly low during the entire frame.
The SCLK can be up to 40 MHz, depending on the IOVDD
voltage level as shown in Table 5. The minimum SCLK
frequency is set by the requirement that all frame data be
clocked out before the next frame becomes available.
By default, a frame contains 11 × 32-bit words when reading at
2 kHz or 16 kHz data rates; similarly, a frame contains 13 × 16-bit
words when reading at 128 kHz. The default frame configuration
does not include the optional respiration phase word; however,
this word can be included as needed. Additionally any words
not required can be excluded from the frame. To arrange the
frame with the words of interest, configure the appropriate bits
in the frame control register (see Table 37). The complete set of
words per frame are 12 × 32-bit words for the 2 kHz or 16 kHz
data rates, or 15 × 16-bit words at 128 kHz.
SCLK (min) = frame_rate × words_per_frame ×
bits_per_word
The minimum SCLK for the various frame rates is shown in
Table 21.
Table 21. SCLK Clock Frequency vs. Packet Data/Frame Rates
Frame
Rate
Word
Size
Maximum
Minimum
SCLK
Words/Frame1
Any data not available within the frame can be read between
frames. Reading a register interrupts the frame and requires the
user to issue a new read command of Address 0x40 (see
Table 54) to start framing again.
128 kHz
16 kHz
2 kHz
16 bits
32 bits
32 bits
15 words
12 words
12 words
30.72 MHz
6.14 MHz
768 kHz
1 This is the full set of words that a frame contains. It is programmable and can
be configured to provide only the words of interest. See Table 37.
Table 22. Default 2 kHz and 16 kHz Data Rate: 32-Bit Frame Word Format
Register
Header
Lead I/LA
Lead II/LL
Lead III/RA
V1’/V1
V2’/V2
PACE
0x1A
RESPM
0x1B
RESPPH
0x1C
LOFF
0x1D
GPIO
0x06
CRC
Address
0x40
0x11
0x12
0x13
0x14
0x15
0x41
Table 23. Default 128 kHz Data Rate: 16-Bit Frame Word Format1
Register Header Lead I/LA Lead II/LL Lead III/RA V1’/V1 V2’/V2 PACE1 PACE2 RESPM1 RESPM2 LOFF GPIO CRC
Address
0x1A 0x1B
0x40 0x11 0x12 0x13 0x14 0x15 0x1D 0x06 0x41
1 Respiration phase words (2 × 16-bit words) are not shown in this frame, but can be included.
Rev. B | Page 51 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Internal operations are synchronized to the internal master
clock at either 2.048 MHz or 1.024 MHz (ECGCTL[3]: HP = 1
and HP = 0, respectively, see Table 28). Because there is no
guaranteed relationship between the internal clock and the
SCLK signal of the SPI, an internal handshaking scheme is used
to ensure safe data transfer between the two clock domains. A
full handshake requires three internal clock cycles and imposes
an upper speed limit on the SCLK frequency when reading
frames with small word counts. This is true for all data frame
rates.
When reading packets of data, the entire data packet must be
DRDY
read; otherwise,
stays low.
DRDY
There are three methods of detecting
status.
DRDY
•
pin. This is an output pin from the ADAS1000/
ADAS1000-1/ADAS1000-2 that indicates the device read
or busy status. No data is valid while this pin is high.
DRDY
The
signals that data is ready to be read by driving
low and remaining low until the entire frame has been
read. It is cleared when the last bit of the last word in the
frame is clocked onto SDO. The use of this pin is optional.
SDO pin. The user can monitor the voltage level of the
SCLK (max) = (1.024 MHz × (1 + HP) × words_per_frame
× bits_per_word)/3; or 40 MHz, whichever is lower.
•
•
CS
SDO pin by bringing
low. If SDO is low, data is ready;
Exceeding the maximum SCLK frequency for a particular
if high, busy. This does not require clocking the SCLK
input. (CPHA = CPOL = 1 only).
DRDY
operating mode causes erratic behavior in the
and results in the loss of data.
signal
One of the first bits of valid data in the header word
available on SDO is a data ready status bit (see Table 43).
Within the configuration of the ADAS1000/ADAS1000-1/
ADAS1000-2, the user can set the header to repeat until
the data is ready. See Bit 6 (RDYRPT) in the frame control
register in Table 37.
Data Rate and Skip Mode
Although the standard frame rates available are 2 kHz, 16 kHz,
and 128 kHz, there is also a provision to skip frames to further
reduce the data rate. This can be configured in the frame
control register (see Table 37).
DRDY
Data Ready (
)
DRDY
as
The host controller must read the entire frame to ensure
DRDY
returns low and ready. If the host controller treats the
DRDY
The
pin is used to indicate that a frame composed of
an edge triggered signal and then misses a frame or underruns,
DRDY
decimated data at the selected data rate is available to read. It is
high when busy and low when ready. Send commands only when
the
remains high because there is still data available to
DRDY
read. The host controller must treat the
signal as level
DRDY
of
initialization is complete,
the status of
DRDY
is low or ready. During power-on, the status
is high (busy) while the device initializes itself. When
DRDY
triggered, ensuring that whenever it goes low, it generates an
interrupt which can initiate a SPI frame transfer. On completion
goes low and the user can start
DRDY
of the transfer the
returns high.
configuring the device for operation. When the device is config-
ured and enabled for conversions by writing to the conversion bit
(CNVEN) in the ECGCTL register, the ADCs start to convert
and the digital interface starts to make data available, loading
them into the buffer when ready. If conversions are enabled
Detecting Missed Conversion Data
To ensure that the current data is valid, the entire frame must
be read at the selected data rate. If a read of the entire frame
takes longer than the selected data rate allows, the internal
buffer is not loaded with the latest conversion data. The frame
header register (see Table 54) provides four settings to indicate
an overflow of frame data. The settings of Bits[29:28] report
how many frames have been missed since the last valid frame
read. A missed frame may occur as a result of the last read
taking too long. The data in the current frame is valid data, but
it is not the current data. It is the calculation made directly after
the last valid read.
DRDY
and the buffer is empty, the device is not ready and
goes
goes low to indicate that
data is ready to be read out of the device. If the device is not
DRDY
high. Once the buffer is full,
DRDY
enabled for conversions, the
buffer full status.
ignores the state of the
To clear such an overflow, the user must read the entire frame.
Rev. B | Page 52 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
CRC Word
ADAS1000
Framed data integrity is provided by CRCs. For the 128 kHz
frame rates, the 16-bit CRC-CCITT polynomial is used. For the
2 kHz and 16 kHz frame rates, the 24-bit CRC polynomial used.
XTAL2
XTAL1
In both cases, the CRC residue is preset to all 1s and inverted
before being transmitted. The CRC parameters are summarized
in Table 24. To verify that data is correctly received, software
computes a CRC on both the data and the received checksum. If
data and checksum are received correctly, the resulting CRC
residue equals the check constant shown in Table 24. Note that
data is shifted through the generator polynomial MSB first, the
same order that it is shifted out serially. The bit and byte order
of the CRC that is appended to the frame is such that the MSB
of the CRC is shifted through the generator polynomial first in
the same order as the data so that the CRC residue XOR’d with
the inverted CRC at the end of the frame is all 1s, which is why
the check constant is identical for all messages. The CRC is
based only on the data that is sent out.
CLK_IO
Figure 80. Input Clock
Clocks
The ADAS1000/ADAS1000-1/ADAS1000-2 run from an
external crystal or clock input frequency of 8.192 MHz.
The external clock input is provided for use in gang mode
so conversions between the two devices are synchronized.
In this mode, the CLK_IO pin is an output from the master
and an input from the slave. To reduce power, the CLK_IO is
disabled when not in gang mode. All features within the
ADAS1000 are a function of the frequency of the externally
applied clock. Using a frequency other than the 8.192 MHz
previously noted causes scaling of the data rates, filter corners,
ac lead off frequency, respiration frequency, and pace algorithm
corners accordingly.
Table 24. CRC Polynomials
Polynomial
Frame Rate
2 kHz, 16 kHz 24 bits
128 kHz 16 bits
CRC Size Polynomial
x24 + x22 + x20 + x19 + x18 + x16 + x14 + x13 + x11 + x10 + x8 + x7 + x6 + x3 + x1 + x0 0x15D6DCB 0x15A0BA
x16 + x12 + x5 + x0
0x11021 0x1D0F
in Hex
Check Constant
Rev. B | Page 53 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
available on MSDO on the falling edge of MSCLK. MSCLK
MCS
SECONDARY SERIAL INTERFACE
idles high when
is deasserted.
This second serial interface is an optional interface that can
be used for the user’s own pace detection purposes. This
interface contains ECG data at 128 kHz data rate only. If using
this interface, the ECG data is still available on the standard
interface discussed previously at lower rates with all the
decimation and filtering applied. If this interface is inactive,
it draws no power.
The data format for this interface is fixed and not influenced by
the FRMCTL register settings. All seven words are output, even
if the individual channels are not enabled.
The header word consists of four bits of all 1s followed by a
12-bit sequence counter. This sequence counter increments
after every frame is sent, thereby allowing the user to tell if
any frames have been missed and how many.
Data is available in 16-bit words, MSB first.
This interface is a master interface, with the ADAS1000/
RESET
CS
ADAS1000-1 providing the SCLK, , SDO. Is it shared
There are two methods of resetting the ADAS1000/ADAS1000-1/
ADAS1000-2 to power-on default. Bringing the
across some of the existing GPIO pins as follows:
RESET
line low
•
•
•
GPIO1/MSCLK
MCS
or setting the SWRST bit in the ECGCTL register (Table 28)
resets the contents of all internal registers to their power-on
GPIO0/
GPIO2/MSDO
RESET
reset state. The falling edge of the
pin initiates the reset
goes high for the duration, returning low when
process is complete. This sequence takes 1.5 ms
DRDY
process;
This interface can be enabled via the GPIO register (see
Table 33).
RESET
the
DRDY
maximum. Do not write to the serial interface while
is
returns low,
RESET
MICROCONTROLLER/
ADAS1000
DSP
RESET
DRDY
command. When
high handling a
normal operation resumes and the status of the
MASTER SPI
pin is
MSCLK/GPIO1
MCS/GPIO0
SCLK
CS
ignored until it goes low again. Software reset using the SWRST
bit (see Table 28) requires that a NOP (no operation) command
be issued to complete the reset cycle.
MISO/GPIO
MSDO/GPIO2
Figure 81. Master SPI Interface for External Pace Detection Purposes
PD FUNCTION
The data format of the frame starts with a header word and five
ECG data-words, as shown in Table 25, and completes with the
same CRC word as documented in Table 24 for the 128 kHz
rate. All words are 16 bits. MSCLK runs at approximately
PD
The
pin powers down all functions in low power mode.
The digital registers maintain their contents. The power-down
function is also available via the serial interface (ECG control
register, see Table 28).
MCS
20 MHz and
is asserted for the entire frame with the data
Table 25. Master SPI Frame Format; All Words are 16 Bits
Mode/Word
1
2
3
4
5
6
7
Electrode mode1
Analog lead mode1
Header
Header
ECG1_LA
LEAD I
ECG2_LL
LEAD III
ECG3_RA
-LEAD II (RA-LL)
ECG4_V1
V1’
ECG5_V2
V2’
CRC
CRC
1 As set by the FRMCTL register data DATAFMT, Bit [4], see Table 37.
Rev. B | Page 54 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
SPI OUTPUT FRAME STRUCTURE (ECG AND STATUS DATA)
Three data rates are offered for reading ECG data: low speed 2 kHz/16 kHz rates for electrode/lead data (32-bit words) and a high speed
128 kHz for electrode/lead data (16-bit words).
DRDY
1
CS
EACH SCLK WORD IS 32 CLOCK CYCLES
1
2
3
4
5
6
7
8
9
10
11
SCLK
SDO
DRIVEN OUTPUT DATA STREAM
2
ANOTHER FRAME OF DATA
32-BIT
DATA WORDS
1
CS MAY BE USED IN ONE OF THE FOLLOWING WAYS:
A) HELD LOW ALL THE TIME.
B) USED TO FRAME THE ENTIRE PACKET OF DATA.
C) USED TO FRAME EACH INDIVIDUAL 32-BIT WORD.
SUPER SET OF FRAME DATA, WORDS MAY BE EXCLUDED.
2
Figure 82. Output Frame Structure for 2 kHz and 16 kHz Data Rates with SDO Data Configured for Electrode or Lead Data
DRDY
CS
1
EACH SCLK WORD IS 16 CLOCK CYCLES
1
2
3
4
5
6
7
8
9
10
11
12
13
SCLK
DRIVEN OUTPUT DATA STREAM
2
SDO
ANOTHER FRAME
16-BIT
DATA WORDS
1
2
CS MAY BE USED IN ONE OF THE FOLLOWING WAYS:
A) HELD LOW ALL THE TIME.
B) USED TO FRAME THE ENTIRE PACKET OF DATA.
C) USED TO FRAME EACH INDIVIDUAL 16-BIT WORD.
SUPER SET OF FRAME DATA, WORDS MAY BE EXCLUDED.
Figure 83. Output Frame Structure for 128 kHz Data Rate with SDO Data Configured for Electrode Data
(The 128 kHz Data Rate Can Provide Single-Ended Electrode Data or Analog Lead Mode Data Only. Digital Lead Mode Is Not Available at 128 kHz Data Rate.)
Rev. B | Page 55 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
SPI REGISTER DEFINITIONS AND MEMORY MAP
In 2 kHz and 16 kHz data rates, data takes the form of 32-bit words. Bit A6 to Bit A0 serve as word identifiers. Each 32-bit word has 24
bits of data. A third high speed data rate is also offered: 128 kHz with data in the form of 16-bit words (all 16 bits as data).
Table 26. SPI Register Memory Map
R/W1
A[6:0]
0x00
0x01
0x02
0x03
0x04
0x05
0x06
0x07
0x08
0x09
0x0A
0x0B
0x0C
0x0D
0x0E
0x0F
0x11
0x12
0x13
0x14
0x15
0x1A
0x1B
0x1C
0x1D
0x1E
0x1F
0x20
0x21
0x22
0x23
0x24
0x25
0x31
0x32
0x33
0x34
0x35
0x3A
0x3B
0x3C
0x40
0x41
Other
D[23:0]
XXXXXX
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
XXXXXX
XXXXXX
XXXXXX
XXXXXX
XXXXXX
XXXXXX
XXXXXX
XXXXXX
XXXXXX
XXXXXX
XXXXXX
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
dddddd
XXXXXX
XXXXXX
Register Name
NOP
ECGCTL
Table
Register Description
NOP (no operation)
ECG control
Reset Value
0x000000
0x000000
0x000000
0x000000
0x000F88
0xE00000
0x000000
0x242424
0x000000
0x002000
0x079000
0x000000
0x00FFFF
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x000000
0x800000
0xFFFFFF
XXXXXX
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
R
R
R
R
R
R
R
R
Table 28
Table 29
Table 30
Table 31
Table 32
Table 33
Table 34
Table 35
Table 36
Table 37
Table 38
Table 39
Table 40
Table 41
Table 42
Table 43
Table 43
Table 43
Table 43
Table 43
Table 44
Table 45
Table 46
Table 47
Table 48
Table 49
Table 50
Table 51
Table 51
Table 51
Table 51
Table 51
Table 52
Table 52
Table 52
Table 52
Table 52
Table 53
Table 53
Table 53
Table 54
Table 55
LOFFCTL
RESPCTL
PACECTL
CMREFCTL
GPIOCTL
PACEAMPTH
TESTTONE
CALDAC
FRMCTL
Lead-off control
Respiration control2
Pace detection control
Common-mode, reference, and shield drive control
GPIO control
Pace amplitude threshold2
Test tone
Calibration DAC
Frame control
FILTCTL
Filter control
LOFFUTH
LOFFLTH
PACEEDGETH
PACELVLTH
LADATA
LLDATA
RADATA
V1DATA
V2DATA
PACEDATA
RESPMAG
RESPPH
LOFF
DCLEAD-OFF
OPSTAT
EXTENDSW
CALLA
CALLL
AC lead-off upper threshold
AC lead-off lower threshold
Pace edge threshold2
Pace level threshold2
LA or Lead I data
LL or Lead II data
RA or Lead III data
V1 or V1’ data
V2 or V2’ data
Read pace detection data/status2
Read respiration data—magnitude2
Read respiration data—phase2
Lead-off status
DC lead-off
Operating state
Extended switch for respiration inputs
User gain calibration LA
User gain calibration LL
User gain calibration RA
User gain calibration V1
User gain calibration V2
Lead-off amplitude for LA
Lead-off amplitude for LL
Lead-off amplitude for RA
Lead-off amplitude for V1
Lead-off amplitude for V2
Pace1 width and amplitude2
Pace2 width and amplitude2
Pace3 width and amplitude2
Frame header
R
R
R/W
R/W
R/W
R/W
R/W
R/W
R
R
R
R
R
R
R
R
R
R
x
CALRA
CALV1
CALV2
LOAMLA
LOAMLL
LOAMRA
LOAMV1
LOAMV2
PACE1DATA
PACE2DATA
PACE3DATA
FRAMES
CRC
Reserved3
Frame CRC
Reserved
1 R/W = register both readable and writable; R = read only.
2 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these features.
3 Reserved bits in any register are undefined. In some cases a physical (but unused) memory bit may be present—in other cases not. Do not issue commands to
reserved registers/space. Read operations of unassigned bits are undefined.
Rev. B | Page 56 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
CONTROL REGISTERS DETAILS
For each register address, the default setting is noted in a default column in addition to being noted in the function column by “(default)”;
this format applies throughout the register map.
Table 27. Serial Bit Assignment
B31
[B30:B24]
[B23:B0]
R/W
Address bits
Data bits (MSB first)
Table 28. ECG Control Register (ECGCTL) Address 0x01, Reset Value = 0x000000
R/W
Default
Bit
23
22
21
20
19
Name
LAEN
LLEN
RAEN
V1EN
V2EN
Function
R/W
R/W
R/W
R/W
R/W
R
0
0
0
0
0
0
0
ECG channel enable; shuts down power to the channel; the input becomes high-Z.
0 (default) = disables ECG channel. When disabled, the entire ECG channel is shut down and
dissipating minimal power.
1 = enables ECG channel.
[18:11] Reserved
Reserved, set to 0.
R/W
10
CHCONFIG Setting this bit selects the differential analog front end (AFE) input. See Figure 58.
0 (default) = single-ended input (digital lead mode or electrode mode).
1 = differential input (analog lead mode).
R/W
00
[9:8]
GAIN [1:0]
Preamplifier and anti-aliasing filter overall gain.
00 (default) = GAIN 0 = ×1.4.
01 = GAIN 1 = ×2.1.
10 = GAIN 2 = ×2.8.
11 = GAIN 3 = ×4.2 (user gain calibration is required for this gain setting).
VREF buffer enable.
0 (default) = disabled.
R/W
R/W
0
0
7
6
VREFBUF
CLKEXT
1 = enabled (when using the internal VREF, VREFBUF must be enabled).
Use external clock instead of crystal oscillator. The crystal oscillator is automatically disabled if
configured as a slave in gang mode, and the slave device receives the clock from the master device.
0 (default) = XTAL is clock source.
1 = CLK_IO is clock source.
R/W
0
5
Master
In gang mode, this bit selects the master (SYNC_GANG pin is configured as an output). When in single
channel mode (gang = 0), this bit is ignored. ADAS1000-2 cannot be configured as a master device.
0 (default) = slave.
1 = master.
R/W
R/W
0
0
4
3
Gang
HP
Enable gang mode. Setting this bit causes CLK_IO and SYNC_GANG to be activated.
0 (default) = single channel mode.
1 = gang mode.
Selects the noise/power performance. This bit controls the ADC sampling frequency. See the
Specifications section for further details. This bit also affects the respiration carrier frequency as
discussed in the Respiration Carrier Frequency section.
0 (default) = 1 MSPS, low power.
1 = 2 MSPS, high performance/low noise.
Conversion enable. Setting this bit enables the ADC conversion and filters.
0 (default) = idle.
R/W
R/W
0
0
2
1
CNVEN
PWREN
1 = conversion enable.
Power enable. Clearing this bit powers down the device. All analog blocks are powered down and the
external crystal is disabled. The register contents are retained during power down as long as DVDD is
not removed.
0 (default) = power down.
1 = power enable.
R/W
0
0
SWRST
Software reset. Setting this bit clears all registers to their reset value. This bit automatically clears itself.
The software reset requires a NOP command to complete the reset.
0 (default) = NOP.
1 = reset.
Rev. B | Page 57 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Table 29. Lead-Off Control Register (LOFFCTL) Address 0x02, Reset Value = 0x000000
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R
Default Bit
Name
Function
0
0
0
0
0
0
0
0
0
0
0
0
0
00
23
22
21
20
19
18
17
16
15
14
13
12
LAPH
LLPH
RAPH
V1PH
V2PH
CEPH
AC lead-off phase.
0 (default) = in phase.
1 = 180° out of phase.
LAACLOEN
LLACLOEN
RAACLOEN
V1ACLOEN
V2ACLOEN
CEACLOEN
Individual electrode ac lead-off enable. AC lead-off enables are the OR of ACSEL and the
individual ac lead-off channel enables.
0 (default) = ac lead-off disabled.
1 = ac lead-off enabled.
[11:9] Reserved
Reserved, set to 0.
R/W
[8:7]
ACCURRENT Set current level for ac lead-off.
00 (default) = 12.5 nA rms.
01 = 25 nA rms.
10 = 50 nA rms.
11 = 100 nA rms.
Reserved, set to 0.
00
[6:5]
[4:2]
Reserved
R/W
000
DCCURRENT Set current level for dc lead-off (active only for ACSEL = 0).
000 (default) = 0 nA.
001 = 10 nA.
010 = 20 nA.
011 = 30 nA.
100 = 40 nA.
101 = 50 nA.
110 = 60 nA.
111 = 70 nA.
R/W
0
1
ACSEL
DC or AC (out-of-band) lead-off detection.
ACSEL acts as a global ac lead-off enable for RA, LL, LA, V1, V2 electrodes (CE ac lead-off is not
enabled using ACSEL). AC lead-off enables are the OR of ACSEL and the individual ac lead-off
channel enables.
If LOFFEN = 0, this bit is don’t care.
If LOFFEN = 1,
0 (default) = dc lead-off detection enabled (individual ac lead-off can be enabled through
Bits[17:12]).
1 = dc lead-off detection disabled. AC lead-off detection enabled (all electrodes except CE
electrode).
When the calibration DAC is enabled, ac lead-off is disabled.
Enable lead-off detection.
R/W
0
0
LOFFEN
0 (default) = lead-off disabled.
1 = lead-off enabled.
Rev. B | Page 58 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
Table 30. Respiration Control Register (RESPCTL) Address 0x03, Reset Value = 0x0000001
R/W
Default Bit
Name
Function
[23:17] Reserved
Reserved, set to 0.
R/W
0
0
16
15
RESPALTFREQ
Setting this bit to 1 makes the respiration waveform on the GPIO3 pin periodic every cycle. Use in
conjunction with RESFREQ to select drive frequency.
0 (default) = periodic every N cycles (default).
1 = periodic every cycle.
R/W
R/W
RESPEXTSYNC
RESPEXTAMP
Set this bit to 1 to drive the MSB of the respiration DAC out onto the GPIO3 pin. This signal can be
used to synchronize an external generator to the respiration carrier. It is a constant period only
when RESPALTFREQ = 1.
0 (default) = normal GPIO3 function.
1 = MSB of RESPDAC driven onto GPIO3 pin.
0
14
For use with an external instrumentation amplifier with respiration circuit. Bypasses the on-chip
amplifier stage and input directly to the ADC. See Figure 71.
0 (default) = disabled.
1 = enabled.
R/W
R/W
R/W
0
13
RESPOUT
RESPCAP
Selects external respiration drive output. RESPDAC_RA is automatically selected when RESPCAP = 1
0 (default) = RESPDAC_LL and RESPDAC_RA.
1 = RESPDAC_LA and RESPDAC_RA.
0
12
Selects source of respiration capacitors.
0 (default) = use internal capacitors.
1 = use external capacitors.
0000
[11:8]
RESPGAIN [3:0] Respiration in amp gain (saturates at 10).
0000 (default) = ×1 gain.
0001 = ×2 gain.
0010 = ×3 gain.
…
1000 = ×9 gain.
1001 = ×10 gain.
11xx = ×10 gain.
R/W
R/W
0
7
RESPEXTSEL
RESPSEL [1:0]
Selects between EXT_RESP_LA or EXT_RESP_LL paths. Applies only if the external respiration is
selected in RESPSEL. EXT_RESP_RA is automatically enabled.
0 (default) = EXT_RESP_LL.
1 = EXT_RESP_LA.
00
[6:5]
Set leads for respiration measurement.
00 (default) = Lead I.
01 = Lead II.
10 = Lead III.
11 = external respiration path.
Set the test tone amplitude for respiration drive signal.
00 (default) = amplitude/8.
01 = amplitude/4.
10 = amplitude/2.
11 = amplitude.
R/W
R/W
00
00
[4:3]
[2:1]
RESPAMP
RESPFREQ
Set frequency for respiration.
RESPFREQ
RESPALTFREQ = 0
56 kHz
RESPALTFREQ = 1 (periodic)
00 (default)
64 kHz
01
10
11
54 kHz
52 kHz
50 kHz
56.9 kHz
51.2 kHz
46.5 kHz
R/W
0
0
RESPEN
Enable respiration.
0 (default) = respiration disabled.
1 = respiration enabled.
1 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these features.
Rev. B | Page 59 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Table 31. Pace Detection Control Register (PACECTL) Address 0x04, Reset Value = 0x000F881
R/W
Default
Bit
Name
Function
[23:12]
11
Reserved
PACEFILTW
Reserved, set to 0
R/W
1
Pace width filter
0 = filter disabled
1 (default) = filter enabled
Pace Validation Filter 2
0 = filter disabled
1 (default) = filter enabled
Pace Validation Filter 1
0 = filter disabled
R/W
R/W
1
1
10
9
PACETFILT2
PACETFILT1
1 (default) = filter enabled
Set lead for pace detection measurement
00 = Lead I
R/W
R/W
R/W
11
00
01
[8:7]
[6:5]
[4:3]
PACE3SEL [1:0]
PACE2SEL [1:0]
PACE1SEL [1:0]
01 = Lead II
10 = Lead III
11 = Lead aVF
R/W
R/W
R/W
0
0
0
2
1
0
PACE3EN
PACE2EN
PACE1EN
Enable pace detection algorithm
0 (default) = pace detection disabled
1 = pace detection enabled
1 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these features.
Rev. B | Page 60 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
Table 32. Common-Mode, Reference, and Shield Drive Control Register (CMREFCTL) Address 0x05, Reset Value = 0xE00000
R/W
R/W
R/W
R/W
R/W
R/W
Default Bit
Name
LACM
LLCM
RACM
V1CM
V2CM
Function
1
1
1
0
0
23
22
21
20
19
Common-mode electrode select.
Any combination of the five input electrodes can be used to create the common-mode
signal, VCM. Bits[23:19] are ignored when Bit 2 is selected. Common mode is the average of
the selected electrodes. When a single electrode is selected, common mode is the signal
level of that electrode alone. The common-mode signal can be driven from the internal
VCM_REF (1.3 V) when Bits [23:19] = 0.
0 = does not contribute to the common mode.
1 = contributes to the common mode.
Reserved, set to 0.
0
0
0
0
0
0
0
0
[18:15] Reserved
R/W
R/W
R/W
R/W
R/W
R/W
R/W
14
13
12
11
10
9
LARLD
LLRLD
RLD summing junction. Note that if the RLD amplifier is disabled (using RLDSEL), these
switches are not automatically forced open, and the user must disable them using Bits[9:14].
RARLD
V1RLD
V2RLD
CERLD
CEREFEN
0 (default) = does not contribute to RLD input.
1 = contributes to RLD input.
8
Common electrode (CE) reference, see Figure 58.
0 (default) = common electrode disabled.
1 = common electrode enabled.
R/W
0000
[7:4]
RLDSEL [3:0]1 Select electrode for reference drive.
0000 (default) = RLD_OUT.
0001 = LA.
0010 = LL.
0011 = RA.
0100 = V1.
0101 = V2.
0110 to 1111 = reserved.
R/W
0
3
DRVCM
Common-mode output. When set, the internally derived common-mode signal is driven out
of the common-mode pin. This bit has no effect if an external common mode is selected.
0 (default) = common mode is not driven out.
1 = common mode is driven out of the external common-mode pin.
Select the source of common mode (use when operating multiple devices together).
0 (default) = internal common mode selected.
1 = external common mode selected (all the internal common-mode switches are off).
Enable right leg drive reference electrode.
R/W
R/W
R/W
0
0
0
2
1
0
EXTCM
RLDSEL1
SHLDEN1
0 (default) = disabled.
1 = enabled.
Enable shield drive.
0 (default) = shield drive disabled.
1 = shield drive enabled.
1 ADAS1000 and ADAS1000-1 models only, ADAS1000-2 models does not contain these features.
Rev. B | Page 61 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Table 33. GPIO Control Register (GPIOCTL) Address 0x06, Reset Value = 0x000000
R/W
Default
Bit
Name
Function
0
0
[23:19] Reserved
Reserved, set to 0
R/W
18
SPIFW
Frame secondary SPI words with chip select
MCS
0 (default) =
asserted for entire frame
asserted for individual word
Reserved, set to 0
MCS
1 =
R/W
R/W
0
0
17
16
Reserved
SPIEN
Secondary SPI enable (ADAS1000 and ADAS1000-1 only); SPI interface providing ECG data at
128 kHz data rate for external digital pace algorithm detection, uses GPIO0, GPIO1, GPIO2 pins
0 (default) = disabled
1 = enabled; he individual control bits for GPIO0, GPIO1, GPIO2 are ignored; GPIO3 is not affected by SPIEN
R/W
00
[15:14] G3CTL [1:0] State of GPIO3 pin
00 (default) = high impedance
01 = input
10 = output
11 = open drain
R/W
R
0
13
12
G3OUT
G3IN
Output value to be written to GPIO3 when the pin is configured as an output or open drain
0 (default) = low value
1 = high value
0
Read only; input value read from GPIO3 when the pin is configured as an input
0 (default) = low value
1 = high value
R/W
00
[11:10] G2CTL [1:0] State of GPIO2 pin
00 (default) = high impedance
01 = input
10 = output
11 = open drain
R/W
R
0
9
G2OUT
G2IN
Output value to be written to GPIO2 when the pin is configured as an output or open drain
0 (default) = low value
1 = high value
0
8
Read only Input value read from GPIO2 when the pin is configured as an input
0 (default) = low value
1 = high value
R/W
00
[7:6]
G1CTL [1:0] State of GPIO1 pin
00 (default) = high impedance
01 = input
10 = output
11 = open drain
R/W
R
0
5
G1OUT
G1IN
Output value to be written to GPIO1 when the pin is configured as an output or open drain
0 (default) = low value
1 = high value
0
4
Read only; input value read from GPIO1 when the pin is configured as an input
0 (default) = low value
1 = high value
R/W
00
[3:2]
G0CTL [1:0] State of the GPIO0 pin
00 (default) = high impedance
01 = input
10 = output
11 = open drain
R/W
R
0
0
1
0
G0OUT
G0IN
Output value to be written to GPIO0 when pin is configured as an output or open drain
0 (default) = low value
1 = high value
(Read only) input value read from GPIO0 when pin is configured as an input
0 (default) = low value
1 = high value
Rev. B | Page 62 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
Table 34. Pace Amplitude Threshold Register (PACEAMPTH) Address 0x07, Reset Value = 0x2424241
R/W
R/W
R/W
R/W
Default
Bit
Name
Function
0010 0100
0010 0100
0010 0100
[23:16]
[15:8]
[7:0]
PACE3AMPTH
PACE2AMPTH
PACE1AMPTH
Pace amplitude threshold
Threshold = N × 2 × VREF/GAIN/216
1 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these features.
Table 35. Test Tone Register (TESTTONE) Address 0x08, Reset Value = 0x000000
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Default
Bit
23
22
21
20
Name
Function
0
0
0
0
TONLA
TONLL
Tone select
0 (default) = 1.3 V VCM_REF
1 = 1 mV sine wave or square wave for TONINT = 1, no connect for TONINT = 0
TONRA
TONV1
TONV2
Reserved
TONTYPE
0
19
0
[18:5]
[4:3]
Reserved, set to 0
00
00 (default) = 10 Hz sine wave
01 = 150 Hz sine wave
1× = 1 Hz, 1 mV square wave
Test tone internal or external
R/W
0
2
TONINT
0 (default) = external test tone; test tone to be sent out through CAL_DAC_IO and
applied externally to enabled channels
1 = internal test tone; disconnects external switches for all ECG channels and
connects the calibration DAC test tone internally to all ECG channels; in gang
mode, the CAL_DAC_IO is connected, and the slave disables the calibration DAC
R/W
R/W
0
0
1
0
TONOUT
TONEN
Test tone out enable
0 (default) = disconnects test tone from CAL_DAC_IO during internal mode only
1 = connects CAL_DAC_IO to test tone during internal mode
Enables an internal test tone to drive entire signal chain, from preamplifier to SPI
interface; this tone comes from the calibration DAC and goes to the preamplifier
through the internal mux; when TONEN (calibration DAC) is enabled, ac lead-off is
disabled
0 (default) = disable the test tone
1 = enable the 1 mV sine wave test tone (calibration mode has priority)
Rev. B | Page 63 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Table 36. Calibration DAC Register (CALDAC) Address 0x09, Reset Value = 0x0020001
R/W
Default
Bit
Name
Function
0
1
[23:14] Reserved
Reserved, set to 0.
R/W
13
CALCHPEN
Calibration chop clock enable. The calibration DAC output (CAL_DAC_IO) can be
chopped to lower 1/f noise. Chopping is performed at 256 kHz.
0 = disabled.
1 (default) = enabled.
R/W
R/W
0
0
12
11
CALMODEEN Calibration mode enable.
0 (default) = disable calibration mode.
1 = enable calibration mode; connect CAL DAC_IO, begin data acquisition on ECG channels.
Calibration internal or external.
CALINT
0 (default) = external calibration to be performed externally by looping CAL_DAC_IO
around into ECG channels.
1 = internal calibration; disconnects external switches for all ECG channels and
connects calibration DAC signal internally to all ECG channels.
R/W
0
10
CALDACEN
Enable 10-bit calibration DAC for calibration mode or external use.
0 (default) = disable calibration DAC.
1 = enable calibration DAC. If a master device and not in calibration mode, also connects
the calibration DAC signal out to the CAL_DAC_IO pin for external use. If in slave mode,
the calibration DAC is disabled to allow master to drive the slave CAL_DAC_IO pin. When
the calibration DAC is enabled, ac lead-off is disabled.
R/W
0000000000 [9:0]
CALDATA[9:0] Set the calibration DAC value.
1 To ensure successful update of the calibration DAC, the serial interface must issue four additional SCLK cycles after writing the new calibration DAC register word.
Rev. B | Page 64 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
Table 37. Frame Control Register (FRMCTL) Address 0x0A, Reset Value = 0x079000
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Default
Bit
23
22
21
20
19
Name
Function
0
0
0
0
LEAD I/LADIS
LEADII/LLDIS
LEADIII/RADIS 0 (default) = included in frame.
V1DIS
V2DIS
Include/exclude word from ECG data frame. If the electrode/lead is included in the data-
word and the electrode falls off, the data-word is undefined.
1 = exclude from frame.
0
1111
0
[18:15] Reserved
Reserved, set to 1111.
Pace detection.
14
13
12
11
10
9
PACEDIS1
RESPMDIS1
RESPPHDIS1
LOFFDIS
0 (default) = included in frame.
1 = exclude from frame.
Respiration magnitude.
0 (default) = included in frame.
1 = exclude from frame.
Respiration phase.
0 = included in frame.
1 (default) = exclude from frame.
Lead-off status.
0 (default) = included in frame.
1 = exclude from frame.
GPIO word disable.
0 (default) = included in frame.
1 = exclude from frame.
CRC word disable.
R/W
R/W
R/W
R/W
R/W
0
1
0
0
0
GPIODIS
CRCDIS
0 (default) = included in frame.
1 = exclude from frame.
Reserved, set to 0.
R/W
R/W
0
0
8
7
RESERVED
ADIS
Automatically excludes PACEDIS[14], RESPMDIS[13], LOFFDIS[11] words if their flags are
not set in the header.
0 (default) = fixed frame format.
1 = autodisable words (words per frame changes).
R/W
0
6
RDYRPT
Ready repeat. If this bit is set and the frame header indicates data is not ready, the frame
header is continuously sent until data is ready.
0 (default) = always send entire frame.
1 = repeat frame header until ready.
Reserved, set to 0 .
R/W
R/W
0
0
5
4
Reserved
DATAFMT
Sets the output data format, see Figure 58.
0 (default) = digital lead/vector format (available only in 2 kHz and 16 kHz data rates).
1 = electrode format.
R/W
R/W
00
00
[3:2]
[1:0]
SKIP[1:0]
Skip interval. This field provides a way to decimate the data.
00 (default) = output every frame.
01 = output every other frame.
1× = output every 4th frame.
FRMRATE[1:0] Sets the output data rate.
00 (default) = 2 kHz output data rate.
01 = 16 kHz output data rate.
10 = 128 kHz output data rate (DATAFMT must be set to 1).
11 = 31.25 Hz.
1 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these features.
Rev. B | Page 65 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Table 38. Filter Control Register (FILTCTL) Address 0x0B, Reset Value = 0x000000
R/W
R/W
R/W
Default
Bit
[23:6]
5
Name
Function
0
0
Reserved
MN2K
Reserved, set to 0
2 kHz notch bypass for SPI master
0 (default) = notch filter bypassed
1 = notch filter present
2 kHz notch bypass
0 (default) = notch filter present
1 = notch filter bypassed
00 (default) = 40 Hz
01 = 150 Hz
R/W
R/W
0
4
N2KBP
00
[3:2]
LPF[1:0]
10 = 250 Hz
11 = 450 Hz
R/W
00
[1:0]
Reserved
Reserved, set to 0
Table 39. AC Lead-Off Upper Threshold Register (LOFFUTH) Address 0x0C, Reset Value = 0x00FFFF
R/W
Default
Bit
Name
Function
0
0
[23:20]
[19:16]
Reserved
ADCOVER[3:0]
Reserved, set to 0
ADC overrange threshold
R/W
An ADC out-of-range error is flagged if the ADC output is greater than the overrange
threshold; the overrange threshold is offset from the maximum value
Threshold = max_value – ADCOVER × 26
0000 = maximum value (disabled)
0001 = max_value – 64
0010 = max_value – 128
…
1111 = max_value − 960
R/W
0xFFFF
[15:0]
LOFFUTH[15:0] Applies to ac lead-off upper threshold only; lead-off is detected if the output is ≥ N ×
2 × VREF/GAIN/216
0 = 0 V
Table 40. AC Lead-Off Lower Threshold Register (LOFFLTH) Address 0x0D, Reset Value = 0x000000
R/W
Default
Bit
Name
Function
0
0
[23:20]
[19:16]
Reserved
Reserved, set to 0
R/W
ADCUNDR[3:0] ADC underrange threshold
An ADC out-of-range error is flagged if the ADC output is less than the underrange
threshold
Threshold = min_value + ADCUNDR × 26
0000 = minimum value (disabled)
0001 = min_value + 64
0010 = min_value + 128
…
1111 = min_value + 960
R/W
0
[15:0]
LOFFLTH[15:0]
Applies to ac lead-off lower threshold only; lead-off is detected if the output is ≤ N ×
2 × VREF/GAIN/216
0 = 0 V
Rev. B | Page 66 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
Table 41. Pace Edge Threshold Register (PACEEDGETH) Address 0x0E, Reset Value = 0x0000001
R/W
R/W
R/W
R/W
Default
Bit
Name
Function
0
0
0
[23:16]
[15:8]
[7:0]
PACE3EDGTH
PACE2EDGTH
PACE1EDGTH
Pace edge trigger threshold
0 = PACEAMPTH/2
1 = VREF/GAIN/216
N = N × VREF/GAIN/216
1 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these features.
Table 42. Pace Level Threshold Register (PACELVLTH) Address 0x0F, Reset Value = 0x0000001
R/W
R/W
R/W
R/W
Default
Bit
Name
Function
0
0
0
[23:16]
[15:8]
[7:0]
PACE3LVLTH[7:0]
PACE2LVLTH[7:0]
PACE1LVLTH[7:0]
Pace level threshold; this is a signed value
−1 = 0xFF = −VREF/GAIN/216
0 = 0x00 = 0 V
+1 = 0x01 = +VREF/GAIN/216
N = N × VREF/GAIN/216
1 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these features.
Table 43. Read Electrode/Lead Data Registers (Electrode/Lead) Address 0x11 to 0x15, Reset Value = 0x0000001
R/W
Default
Bit
Name
Function
[31:24]
Address [7:0]
0x11: LA or Lead I.
0x12: LL or Lead II.
0x13: RA or Lead III.
0x14: V1 or V1’.
0x15: V2 or V2’.
R
0
[23:0]
ECG data
Channel data value. Data left justified (MSB) irrespective of data rate.
The input stage can be configured into different modes (electrode, analog lead, or digital
lead) as shown in Table 11. In electrode mode and analog lead mode, the digital result
value is an unsigned integer.
In digital lead/vector mode, the value is a signed twos complement integer format and has
a 2× range compared to electrode format because it can swing from +VREF to –VREF;
therefore, the LSB size is doubled.
Electrode mode and analog lead mode:
Minimum value (000…) = 0 V
Maximum value (1111….) = VREF/GAIN
LSB = (2 × VREF/GAIN)/(2N– 1)
ECG (voltage) = ECG Data × (2 × VREF/GAIN)/(2N– 1)
Digital lead mode:
Minimum value (1000…) = −(VREF/GAIN)
Maximum value (0111….) = +VREF/GAIN
LSB = (4 × VREF/GAIN)/(2N – 1)
ECG (voltage) = ECG Data × (4 × VREF/GAIN)/(2N – 1)
where N = number of data bits: 16 for 128 kHz data rate or 24 for 2 kHz/16 kHz data rate.
1 If using 128 kHz data rate in frame mode, only the upper 16 bits are sent. If using the 128 kHz data rate in regular read/write mode, all 32 bits are sent.
Rev. B | Page 67 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Table 44. Read Pace Detection Data/Status Register (PACEDATA) Address 0x1A, Reset Value = 0x0000001, 2, 3
R/W
Default Bit
Name
Function
R
0
23
Pace 3 detected
Pace 3 detected. This bit is set once a pace pulse is detected. This bit is set on the
trailing edge of the pace pulse.
0 = pace pulse not detected in current frame.
1 = pace pulse detected in this frame.
This bit is log2 (width) − 1 of the pace pulse.
Width = 2N + 1/128 kHz.
R
R
R
000
0000
0
[22:20]
[19:16]
15
Pace Channel 3 width
Pace Channel 3 height
Pace 2 detected
This bit is the log2 (height) of the pace pulse.
Height = 2N × VREF/GAIN/216.
Pace 2 detected. This bit is set once a pace pulse is detected. This bit is set on the
trailing edge of the pace pulse.
0 = pace pulse not detected in current frame.
1 = pace pulse detected in this frame.
This bit is log2 (width) − 1 of the pace pulse.
Width = 2N + 1/128 kHz.
R
R
R
000
0000
0
[14:12]
[11:8]
7
Pace Channel 2 width
Pace Channel 2 height
Pace 1 detected
This bit is the log2 (height) of the pace pulse.
Height = 2N × VREF/GAIN/216.
Pace 1 detected. This bit is set once a pace pulse is detected. This bit is set on the
trailing edge of the pace pulse.
0 = pace pulse not detected in current frame.
1 = pace pulse detected in this frame.
This bit is log2 (width) − 1 of the pace pulse.
Width = 2N + 1/128 kHz.
R
R
000
[6:4]
[3:0]
Pace Channel 1 width
Pace Channel 1 height
0000
This bit is the log2 (height) of the pace pulse.
Height = 2N × VREF/GAIN/216.
1 If using 128 kHz data rate in frame mode, this word is stretched over two 16-bit words. If using the 128 kHz data rate in regular read/write mode, all 32 bits are sent.
2 Log data for width and height is provided here to ensure that it fits in one full 32-bit data-word. As a result there may be some amount of error in the resulting value.
For more accurate reading, read Register 0x3A, Register 0x3B, and Register 0x3C (see Table 53).
3 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these features.
Table 45. Read Respiration Data—Magnitude Register (RESPMAG) Address 0x1B, Reset Value = 0x0000001, 2
R/W
Default Bit
[23:0]
Name
Function
R
0
Respiration magnitude[23:0]
Magnitude of respiration signal. This is an unsigned value.
4 × (VREF/(1.6468 × respiration gain))/(224 – 1).
1 If using 128 kHz data rate in frame mode, this word is stretched over two 16-bit words. If using the 128 kHz data rate in regular read/write mode, all 32 bits are sent.
2 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these features.
Table 46. Read Respiration Data—Phase Register (RESPPH) Address 0x1C, Reset Value = 0x0000001, 2
R/W
Default Bit
[23:0]
Name
Function
R
0
Respiration
phase[23:0]
Phase of respiration signal. Can be interpreted as either signed or unsigned value. If
unsigned, the range is from 0 to 2π. If signed, the range is from – π to +π.
0x000000 = 0.
0x000001 = 2π/224.
0x400000 = π/2.
0x800000 = +π = − π.
0xC00000 = +3π/2 = − π/2.
0xFFFFFF = +2π(1 − 2−24) = −2π/224.
1 This register is not part of framing data, but may be read by issuing a register read command of this address.
2 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these features.
Rev. B | Page 68 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
Table 47. Lead-Off Status Register (LOFF) Address 0x1D, Reset Value = 0x000000
R/W
Default
Bit
23
22
21
20
19
18
13
Name
Function
R
0
RLD lead-off status
LA lead-off status
LL lead-off status
RA lead-off status
V1 lead-off status
V2 lead-off status
CELO
Electrode connection status.
If either dc or ac lead-off is enabled, these bits are the corresponding lead-off status. If
both dc and ac lead-off are enabled, these bits reflect only the ac lead-off status. DC
lead-off is available in the DCLEAD-OFF register (see Table 48).
The common electrodes have only dc lead-off detection.
An ac lead-off signal can be injected into the common electrode, but there is no ADC
input to measure its amplitude. If the common electrode is off, it affects the ac lead-off
amplitude of the other electrodes.
These bits accumulate in the frame buffer and are cleared when the frame buffer is
loaded into the SPI buffer.
0 = electrode is connected.
1 = electrode is disconnected.
RLD lead-off is not detected in ac lead-off.
Reserved.
R
R
0
0
[17:14] Reserved
12
11
10
9
LAADCOR
LLADCOR
RAADCOR
V1ADCOR
V2ADCOR
Reserved
ADC out of range error.
These status bits indicate the resulting ADC code is out of range.
These bits accumulate in the frame buffer and are cleared when the frame buffer is
loaded into the SPI buffer.
8
R
0
[7:0]
Reserved.
Table 48. DC Lead-Off Register (DCLEAD-OFF) Address 0x1E, Reset Value = 0x0000001
R/W
Default
Bit
Name
Function
R
0
23
RLD input
overrange
The dc lead-off detection is comparator based and compares to a fixed level. Individual
electrode bits flag indicate if the dc lead-off comparator threshold level has been exceeded.
22
21
20
LA input overrange 0 = electrode < overrange threshold, 2.4 V.
LL input overrange 1 = electrode > overrange threshold, 2.4 V.
RA input
overrange
19
18
13
V1 input overrange
V2 input overrange
CE input overrange
R
R
0
0
[17:14] Reserved
[6:3]
Reserved.
12
11
10
9
RLD input
underrange
The dc lead-off detection is comparator based and compares to a fixed level. Individual
electrode bits indicate if the dc lead-off comparator threshold level has been exceeded.
LA input
underrange
0 = electrode > underrange threshold, 0.2 V.
LL input
underrange
1 = electrode < underrange threshold, 0.2 V.
RA input
underrange
8
7
2
V1 input overrange
V2 input overrange
CE input
underrange
R
0
[1:0]
Reserved
1 This register is not part of framing data, but can be read by issuing a register read command of this address.
Rev. B | Page 69 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Table 49. Operating State Register (OPSTAT) Address 0x1F, Reset Value = 0x0000001
R/W
Default Bit
Name
Function
R
0
0
0
[23:4] Reserved
Reserved.
R
3
2
Internal error
Internal digital failure. This is set if an error is detected in the digital core.
R
Configuration status
This bit is set after a reset indicating that the configuration has not been read yet.
Once the configuration is set, this bit is ready.
0 = ready.
1 = busy.
R
R
0
0
1
0
PLL lock
PLL lock lost. This bit is set if the internal PLL loses lock after it is enabled and locked.
This bit is cleared once this register is read or the PWREN bit (Address 0x01[1]) is cleared.
0 = PLL locked.
1 = PLL lost lock.
PLL locked status
This bit indicates the current state of the PLL locked status.
0 = PLL not locked.
1 = PLL locked.
1 This register is not part of framing data, but can be read by issuing a register read command of this address. This register assists support efforts giving insight into
potential areas of malfunction within a failing device.
Table 50. Extended Switch for Respiration Inputs Register (EXTENDSW) Address 0x20, Reset Value = 0x000000
R/W
Default Bit
Name
Switch Function
R/W
0
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
EXT_RESP_RA to ECG1_LA
EXT_RESP_RA to ECG2_LL
EXT_RESP_RA to ECG3_RA
EXT_RESP_RA to ECG4_V1
EXT_RESP_RA to ECG5_V2
EXT_RESP_LL to ECG1_LA
EXT_RESP_LL to ECG2_LL
EXT_RESP_LL to ECG3_RA
EXT_RESP_LL to ECG4_V1
EXT_RESP_LL to ECG5_V2
EXT_RESP_LA to ECG1_LA
EXT_RESP_LA to ECG2_LL
EXT_RESP_LA to ECG3_RA
EXT_RESP_LA to ECG4_V1
EXT_RESP_LA to ECG5_V2
AUX_V1
SW1a
SW1b
SW1c
SW1d
SW1e
SW2a
SW2b
SW2c
SW2d
SW2e
SW3a
SW3b
SW3c
SW3d
SW3e
External respiration electrode input switch to channel electrode input (see
Figure 72).1
0 = switch open.
1 = switch closed.
R/W
R/W
0
0
8
V1 and V2 electrodes can be used for measurement purposes other than ECG.
7
AUX_V2
To achieve this, they must be disconnected from the patient VCM voltage
provided from the internal common-mode buffer and, instead, connected to
the internal VCM_REF level of 1.3 V.
Setting the AUX_Vx bits high connects the negative input of the V1 and V2
channel amplifier to internal VCM_REF level. This allows the user to make
alternative measurements on V1 and V2 relative to the VCM_REF level.
Note that the V1 and V2 measurements are now being made outside of the
right leg drive loop, therefore there is increased noise on the measurement
as a result.
R/W
0
[6:0]
Reserved
Reserved, set to 0.
1 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these EXT_RESP_xx pins.
Rev. B | Page 70 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
Table 51. User Gain Calibration Registers (CALxx) Address 0x21 to Address 0x25, Reset Value = 0x000000
R/W
Default Bit
[31:24]
Name
Function
Address [7:0]
0x21: calibration LA.
0x22: calibration LL.
0x23: calibration RA.
0x24: calibration V1.
0x25: calibration V2.
R/W
0
23
USRCAL
User can choose between default calibration values or user calibration values for GAIN 0,
GAIN 1, GAIN 2.
Note that for GAIN 3, there is no factory calibration.
0 = default calibration values (factory calibration).
1 = user calibration values.
R/W
R/W
0
0
[22:12]
[11:0]
Reserved
Reserved, set to 0
CALVALUE
Gain calibration value.
Result = data × (1 + GAIN × 2−17).
The value read from this register is the current gain calibration value. If the USRCAL bit is set
to 0, this register returns the default value for the current gain setting.
0x7FF (+2047) = ×1.00000011111111111b.
0x001 (+1) = ×1.00000000000000001b.
0x000 (0) = ×1.00000000000000000b.
0xFFF (−1) = ×0.11111111111111111b.
0x800 (−2048) = ×0.11111100000000000b.
Table 52. Read AC Lead-Off Amplitude Registers (LOAMxx) Address 0x31 to Address 0x35, Reset Value = 0x0000001
R/W
Default Bit
[31:24]
Name
Function
Address [7:0]
0x31: LA ac lead-off amplitude.
0x32: LL ac lead-off amplitude.
0x33: RA ac lead-off amplitude.
0x34: V1 ac lead-off amplitude.
0x35: V2 ac lead-off amplitude.
Reserved.
R/W
R
0
0
[23:16]
[15:0]
Reserved
LOFFAM
Measured amplitude.
When ac lead-off is selected, the data is the average of the rectified 2 kHz band-pass filter
with an update rate of 8 Hz and cutoff frequency at 2 Hz. The output is the amplitude of the
2 kHz signal scaled by 2/π approximately = 0.6 (average of rectified sine wave). To convert to
RMS, scale the output by π/(2√2).
Lead-off (unsigned).
Minimum 0x0000 = 0 V.
LSB 0x0001= VREF/GAIN/216.
Maximum 0xFFFF = VREF/GAIN.
RMS = [π/(2√2)] × [(Code × VREF)/(GAIN × 216)]
Peak-to-peak = π × [(Code × VREF)/(GAIN × 216)]
1 This register is not part of framing data, but can be read by issuing a register read command of this address.
Rev. B | Page 71 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Table 53. Pace Width and Amplitude Registers (PACExDATA) Address 0x3A to Address 0x3C, Reset Value = 0x0000001, 2
R/W
Default Bit
[31:24]
Name
Function
Address [7:0]
0x3A: PACE1DATA
0x3B: PACE2DATA
0x3C: PACE3DATA
R
R
0
0
[23:8]
[7:0]
Pace height
Pace width
Measured pace height in signed two’s complement value
0 = 0
1 = VREF/GAIN/216
N = 2 × N × VREF/GAIN/216
Measured pace width in 128 kHz samples
N: (N + 1)/128 kHz = width
12: (12 + 1)/128 kHz = 101.56 µs (minimum when pace width filter enabled)
255: (255 + 1)/128 kHz = 2.0 ms
Disabling the pace width filter allows the pace measurement system to
return values of N < 12, that is, pulses narrower than 101.56 μs.
1 These registers are not part of framing data but can be read by issuing a register read command of these addresses.
2 ADAS1000 model only, ADAS1000-1/ADAS1000-2 models do not contain these features.
Rev. B | Page 72 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
Table 54. Frame Header (FRAMES) Address 0x40, Reset Value = 0x8000001
R/W
Default
Bit
31
30
Name
Function
R
1
0
Marker
Ready bit
Header marker, set to 1 for the header.
Ready bit indicates if ECG frame data is calculated and ready for reading.
0 = ready, data frame follows.
R
1 = busy.
R
0
[29:28]
Overflow [1:0]
Overflow bits indicate that since the last frame read, a number of frames have
been missed. This field saturates at the maximum count. The data in the frame
including this header word is valid but old if the overflow bits are >0.
When using skip mode (FRMCTL register (0x0A), Bits[3:2]), the overflow bit acts as a
flag, where a nonzero value indicates an overflow.
00 = 0 missed.
01 = 1 frame missed.
10 = 2 frames missed.
11 = 3 or more frames missed.
Internal device error detected.
0 = normal operation.
R
R
R
R
0
0
0
0
27
26
25
24
Fault
1 = error condition.
Pace 3 detected
Pace 2 detected
Pace 1 detected
Pace 3 indicates pacing artifact was qualified at most recent point.
0 = no pacing artifact.
1 = pacing artifact present.
Pace 2 indicates pacing artifact was qualified at most recent point.
0 = no pacing artifact.
1 = pacing artifact present.
Pace 1 indicates pacing artifact was qualified at most recent point.
0 = no pacing artifact.
1 = pacing artifact present.
R
R
0
0
23
22
Respiration
0 = no new respiration data.
1 = respiration data updated.
Lead-off detected
If both dc and ac lead-off are enabled, this bit is the OR of all the ac lead-off detect
flags. If only ac or dc lead-off is enabled, this bit reflects the OR of all dc and ac
lead-off flags.
0 = all leads connected.
1 = one or more lead-off detected.
0 = all leads connected.
1 = one or more lead-off detected.
0 = ADC within range.
1 = ADC out of range.
R
R
0
0
0
21
DC lead-off detected
ADC out of range
Reserved
20
[19:0]
Reserved
1 If using 128 kHz data rate in frame mode, only the upper 16 bits are sent. If using the 128 kHz data rate in regular read/write mode, all 32 bits are sent.
Table 55. Frame CRC Register (CRC) Address 0x41, Reset Value = 0xFFFFFF1
R/W
Bit
Name
Function
R
[23:0]
CRC
Cyclic redundancy check
1 The CRC register is a 32-bit word for 2 kHz and 16 kHz data rate and a 16-bit word for 128 kHz rate. See Table 24 for more details.
Rev. B | Page 73 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
EXAMPLES OF INTERFACING TO THE ADAS1000
The following examples shows register commands required to
configure the ADAS1000 device into particular modes of
operation and to start framing ECG data.
Example 2: Enable Respiration and Stream Conversion
Data
1. Write 1 configures the RESPCTL register with a 56 kHz
respiration drive signal, gain = 1, driving out through
the respiration capacitors and measuring on Lead I.
2. Write 2 issues the read command to start putting the
converted data out on the SDO pin.
Example 1: Initialize the ADAS1000 for ECG Capture and
Start Streaming Data
1. Write 1 configures the CMREFCTL register for CM =
WCT = (LA + LL + RA)/3; RLD is enabled onto the
RLD_OUT electrode. The shield amplifier is enabled.
2. Write 2 configures the FRMCTL register to output nine
words per frame/packet. The frame/packet of words
consist of the header, five ECG words, pace, respiration
magnitude, and lead-off. The frame is configured to
always send, irrespective of ready status. The ADAS1000
is in analog lead format mode with a data rate of 2 kHz.
3. Write 3 addresses the ECGCTL register, enabling all
channels into a gain of 1.4, low noise mode, and differen-
tial input, which configures the device for analog lead
mode. This register also configures the device as a master,
using the external crystal as the input source to the XTALx
pins. The ADAS1000 is also put into conversion mode in
this write.
3. Continue to issue SCLK cycles to read the converted data
at the configured packet data rate.
4. Note that this example assumes that the FRMCTL register
has already been configured such that the respiration
magnitude is available in the data frame, as arranged in
Write 2 of Example 1.
Example 3: DC Lead-Off and Stream Conversion Data
1. Write 1 configures the LOFFCTL register with a dc lead-off
enabled for a lead-off current of 50 nA.
2. Write 2 issues the read command to start putting the
converted data out on the SDO pin.
3. Continue to issue SCLK cycles to read the converted
data at the configured packet data rate.
4. Note that this example assumes that the FRMCTL register
has already been configured such that the dc lead-off word
is available in the data frame, as arranged in Write 2 of
Example 1.
4. Write 4 issues the read command to start putting the
converted data out on the SDO pin.
5. Continue to issue SCLK cycles to read the converted data
at the configured packet data rate (2 kHz). The SDI input
must be held low when reading back the conversion data
because any commands issued to the interface during read
of frame/packet are understood to be a change of configu-
ration data and stop the ADC conversions to allow the
interface to process the new command.
Table 56. Example 1: Initialize the ADAS1000 for ECG Capture and Start Streaming Data
Write Command
Register Addressed
CMREFCTL
FRMCTL
ECGCTL
FRAMES
Read/Write Bit
Register Address
Data
32-Bit Write Command
0x85E0000B
0x8A079600
0x81F804AE
0x40000000
Write 1
Write 2
Write 3
Write 4
1
1
1
0
000 0101
000 1010
000 0001
100 0000
1110 0000 0000 0000 0000 1011
0000 0111 1001 0110 0000 0000
1111 1000 0000 0100 1010 1110
0000 0000 0000 0000 0000 0000
Table 57. Example 2: Enable Respiration and Stream Conversion Data
Write Command
Register Addressed
Read/Write Bit
Register Address
Data
32-Bit Write Command
0x83002099
0x40000000
Write 1
Write 2
RESPCTL
FRAMES
1
0
000 0011
100 0000
0000 0000 0010 0000 1001 1001
0000 0000 0000 0000 0000 0000
Table 58. Example 3: Enable DC Lead-Off and Stream Conversion Data
Write Command
Register addressed
Read/Write Bit
Register Address
Data
32-Bit Write Command
0x82000015
0x40000000
Write 1
Write 2
LOFFCTL
FRAMES
1
0
000 0010
100 0000
0000 0000 0000 0000 0001 0101
0000 0000 0000 0000 0000 0000
Rev. B | Page 74 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
Example 4: Configure 150 Hz Test Tone Sine Wave on
Each ECG Channel and Stream Conversion Data
Example 5: Enable Pace Detection and Stream
Conversion Data
1. Write 1 configures the CMREFCTL register to VCM_REF
= 1.3 V (no electrodes contribute to VCM). RLD is enabled
to RLD_OUT, and the shield amplifier enabled.
2. Write 2 addresses the TESTTONE register to enable the
150 Hz sine wave onto all electrode channels.
1. Write 1 configures the PACECTL register with all three
pace detection instances enabled, PACE1EN detecting on
Lead II, PACE2EN detecting on Lead I, and PACE3EN
detecting on Lead aVF. The pace width filter and validation
filters are also enabled.
3. Write 3 addresses the FILTCTL register to change the internal
low-pass filter to 250 Hz to ensure that the 150 Hz sine
wave can pass through.
2. Write 2 issues the read command to start putting the
converted data out on the SDO pin.
3. Continue to issue SCLK cycles to read the converted data
at the configured packet data rate. When a valid pace is
detected, the detection flags are confirmed in the header
word and the PACEDATA register contains information
on the width and height of the measured pulse from each
measured lead.
4. Note that the PACEAMPTH register default setting is
0x242424, setting the amplitude of each of the pace
instances to 1.98 mV/gain.
4. Write 4 configures the FRMCTL register to output nine words
per frame/packet. The frame/packet of words consists of the
header and five ECG words, pace, respiration magnitude,
and lead-off. The frame is configured to always send,
irrespective of ready status. The ADAS1000 is in electrode
format mode with a data rate of 2 kHz. Electrode format is
required to see the test tone signal correctly on each
electrode channel.
5. Write 5 addresses the ECGCTL register, enabling all
channels into a gain of 1.4, low noise mode. It configures
the device as a master and driven from the XTAL input
source. The ADAS1000 is also put into conversion mode
in this write.
5. Note that this example assumes that the FRMCTL register
has already been configured such that the PACEDATA
word is available in the data frame, as arranged in Write 2
of Example 1.
6. Write 6 issues the read command to start putting the
converted data out on the SDO pin.
7. Continue to issue SCLK cycles to read the converted data
at the configured packet data rate.
Table 59. Example 4: Configure 150 Hz Test Tone Sine Wave on Each ECG Channel and Stream Conversion Data
Write Command
Register Addressed
CMREFCTL
TESTTONE
FILTCTL
FRMCTL
ECGCTL
Read/Write Bit Register Address
Data
32-Bit Write Command
Write 1
Write 2
Write 3
Write 4
Write 5
Write 6
1
1
1
1
1
0
000 0101
000 1000
000 1011
000 1010
000 0001
100 0000
0000 0000 0000 0000 0000 1011
1111 1000 0000 0000 0000 1101
0000 0000 0000 0000 0000 1000
0000 0111 1001 0110 0001 0000
1111 1000 0000 0000 1010 1110
0000 0000 0000 0000 0000 0000
0x8500000B
0x88F8000D
0x8B000008
0x8A079610
0x81F800AE
0x40000000
FRAMES
Table 60. Example 5: Enable Pace Detection and Stream Conversion Data
Write Command
Register Addressed Read/Write Bit
Register Address
Data
32-Bit Write Command
0x84000F8F
0x40000000
Write 1
Write 2
PACECTL
FRAMES
1
0
000 0100
100 0000
0000 0000 0000 1111 1000 1111
0000 0000 0000 0000 0000 0000
Rev. B | Page 75 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
Example 6: Writing to Master and Slave Devices and Streaming Conversion Data
Slave Configuration
Master Configuration
1. Write 1 configures the FRMCTL register to output seven
words per frame/packet. The frame/packet of words consist
of the header, five ECG words, and lead-off. The frame is
configured to always send, irrespective of ready status. The
slave ADAS1000-2 is in electrode mode format with a data
rate of 2 kHz.
1. Write 4 configures the FRMCTL register to output nine
words per frame/packet (note that this differs from the
number of words in a frame available from the slave
device). The frame/packet of words consists of the header,
five ECG words, pace, respiration magnitude, and lead-off.
In this example, the frame is configured to always send
irrespective of ready status. The master, ADAS1000, is in
vector mode format with a data rate of 2 kHz. Similar
to the slave device, the master could be configured for
electrode mode; the host controller would then be required
to make the lead calculations.
2. Write 2 configures the CMREFCTL register to receive an
external common mode from the master.
3. Write 3 addresses the ECGCTL register, enabling all
channels into a gain of 1.4, low noise mode. It configures
the device as a slave, in gang mode and driven from the
CLK_IN input source (derived from master ADAS1000).
The ADAS1000-2 slave is also put into conversion mode
in this write, but waits for the SYNC_GANG signal from
the master device before it starts converting.
2. Write 5 configures the CMREFCTL register for CM =
WCT = (LA + LL + RA)/3; RLD is enabled onto
RLD_OUT electrode. The shield amplifier is enabled.
The CM = WCT signal is driven out of the master device
(CM_OUT) into the slave device (CM_IN).
3. Write 6 addresses the ECGCTL register, enabling all
channels into a gain of 1.4, low noise mode. It configures
the device as a master in gang mode and driven from
the XTAL input source. The ADAS1000 master is set to
differential input, which places it in analog lead mode.
This ECGCTL register write puts the master into
conversion mode, where the device sends an edge on
the SYNC_GANG pin to the slave device to trigger the
simultaneous conversions of both devices.
4. Write 7 issues the read command to start putting the
converted and decimated data out on the SDO pin.
5. Continue to issue SCLK cycles to read the converted data
at the configured packet data rate.
Table 61. Example 6: Writing to Master and Slave Devices and Streaming Conversion Data
Device Write Command
Register Addressed
R/W Register Address
Data
32-Bit Write Command
0x8A07F610
0x85000004
Slave
Write 1
Write 2
Write 3
Write 4
Write 5
Write 6
Write 7
FRMCTL
CMREFCTL
ECGCTL
1
1
1
1
1
1
0
000 1010
000 0101
000 0001
000 1010
000 0101
000 0001
100 0000
0000 0111 1111 0110 0001 0000
0000 0000 0000 0000 0000 0100
1111 1000 0000 0000 1101 1110
0000 0111 1001 0110 0000 0000
1110 0000 0000 0000 0000 1011
1111 1000 0000 0100 1011 1110
0000 0000 0000 0000 0000 0000
0x81F800DE
Master
FRMCTL
CMREFCTL
ECGCTL
0x8A079600
0x85E0000B
0x81F804BE
0x40000000
FRAMES
Rev. B | Page 76 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
SOFTWARE FLOWCHART
Figure 84 shows a suggested sequence of steps to be taken to interface to multiple ADAS1000/ADAS1000-1/ADAS1000-2 devices.
POWER UP ADAS1000
DEVICES
WAIT FOR POR ROUTINE
TO COMPLETE, 1.5ms
INITIALIZE SLAVE
DEVICES
INITIALIZE MASTER DEVICE
ENABLING CONVERSION
ISSUE READ FRAME
COMMAND (WRITE TO 0x40)
NO
DRDY
LOW?
YES
ISSUE SCLK CYCLES (SDI = 0)
TO CLOCK FRAME DATA OUT
AT PROGRAMMED DATA RATE
NO
DISCARD
FRAME DATA
IS CRC
CORRECT?
YES
NO
ACTIVITY
ON
SDI?
YES
ADAS1000 STOPS CONVERTING,
SDI WORD USED TO
RECONFIGURE DEVICE
RETURN
TO ECG
CAPTURE?
NO
YES
ISSUE READ FRAME
COMMAND (WRITE TO 0x40)
NO
POWER-DOWN?
YES
ECG CAPTURE COMPLETE
POWER-DOWN ADAS1000
ECGCTL = 0x0
ADAS1000 GOES INTO
POWER-DOWN MODE
Figure 84. Suggested Software Flowchart for Interfacing to Multiple ADAS1000/ADAS1000-1/ADAS1000-2 Devices
Rev. B | Page 77 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
POWER SUPPLY, GROUNDING, AND DECOUPLING
STRATEGY
ADCVDD AND DVDD SUPPLIES
The AVDD supply rail powers the analog blocks in addition to
the internal 1.8 V regulators for the ADC and the digital core.
If using the internal regulators, connect the VREG_EN pin to
AVDD and then use the ADCVDD and DVDD pins for
decoupling purposes.
The ADAS1000/ADAS1000-1/ADAS1000-2 must have ample
supply decoupling of 0.01 μF on each supply pin located as close
to the device pin as possible, ideally right up against the device.
In addition, there must be one 4.7 μF capacitor for each of the
power domains, AVDD and IOVDD, again located as close to
the device as possible. IOVDD is best split from AVDD due to
its noisy nature.
The DVDD regulator can be used to drive other external digital
circuitry as required; however the ADCVDD pin is purely
provided for bypassing purposes and does not have available
current for other components.
Similarly, the ADCVDD and DVDD power domains each
require one 2.2 μF capacitor with ESR in the range of 0.5 Ω to
2 Ω. The ideal location for each 2.2 μF capacitor is dependent
on package type. For the LQFP package and DVDD decoupling,
the 2.2 μF capacitor is best placed between Pin 30 and Pin 31,
while for ADCVDD, place the 2.2 μF capacitor between Pin 55
and Pin 56. Similarly for the LFCSP package, the DVDD 2.2 μF
capacitor is ideal between Pin 43 and Pin 44, and between Pin 22
and Pin 23 for ADCVDD. A 0.01 μF capacitor is recommended
for high frequency decoupling at each pin. The 0.01 μF capacitors
must have low effective series resistance (ESR) and effective series
inductance (ESL), such as the common ceramic capacitors that
provide a low impedance path to ground at high frequencies to
handle transient currents due to internal logic switching.
Where overall power consumption must be minimized, using
external 1.8 V supply rails for both ADCVDD and DVDD
would provide a more efficient solution. The ADCVDD and
DVDD inputs have been designed to be driven externally and
the internal regulators can be disabled by tying VREG_EN pin
directly to ground.
UNUSED PINS/PATHS
In applications where not all ECG paths or functions might be
used, the preferred method of biasing the different functions is
as follows:
•
Unused ECG paths power up disabled. For low power
operation, keep them disabled throughout operation.
Ideally, connect these pins to RLD_OUT if not being used.
Unused external respiration inputs can be tied to ground if
not in use.
Avoid digital lines running under the device because these
couple noise onto the device. Allow the analog ground plane to
run under the device to avoid noise coupling. The power supply
lines must use as large a trace as possible to provide low impedance
paths and reduce the effects of glitches on the power supply
line. Shield fast switching digital signals with digital ground to
avoid radiating noise to other parts of the board and never run
them near the reference inputs. It is essential to minimize noise
on VREF lines. Avoid crossover of digital and analog signals.
Traces on opposite sides of the board must run at right angles to
each other. This reduces the effects of feedthrough throughout
the board. As is the case for all thin packages, take care to avoid
flexing the package and to avoid a point load on the surface of
this package during the assembly process.
•
•
•
If unused, the shield driver can be disabled and output left
to float.
DRDY
CM_OUT, CAL_DAC_IO,
SYNC_GANG can be left open.
, GPIOx, CLK_IO,
LAYOUT RECOMMENDATIONS
To maximize CMRR performance, pay careful attention to
the ECG path layout for each channel. All channels must be
identical to minimize difference in capacitance across the paths.
Place all decoupling as close to the ADAS1000/ADAS1000-1/
ADAS1000-2 devices as possible, with an emphasis on ensuring
that the VREF decoupling be prioritized, with VREF decoupling
on the same side as the ADAS1000/ADAS1000-1/ADAS1000-2
devices, where possible.
During layout of board, ensure that bypass capacitors are placed
as close to the relevant pin as possible, with short, wide traces
ideally on the topside.
AVDD
While the ADAS1000/ADAS1000-1/ADAS1000-2 are
designed to operate from a wide supply rail, 3.15 V to 5.5 V,
the performance is similar over the full range, but overall
power increases with increasing voltage.
Rev. B | Page 78 of 80
Data Sheet
ADAS1000/ADAS1000-1/ADAS1000-2
OUTLINE DIMENSIONS
9.10
9.00 SQ
8.90
0.60
0.42
0.24
0.275
0.60
0.42
0.24
0.150
43
56
42
1
PIN 1
INDICATOR
8.75
BSC SQ
0.50
BSC
6.05
5.95 SQ
5.85
*
EXPOSED PAD
0.75
0.65
0.55
29
14
15
28
TOP VIEW
BOTTOM VIEW
6.50 REF
0.70 MAX
0.65 NOM
12° MAX
0.90
0.85
0.80
0.05 MAX
0.01 NOM
0.30
0.23
0.18
SEATING
PLANE
0.20 REF
*
FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
Figure 85. 56-Lead, Lead Frame Chip Scale Package [LFCSP_VQ]
9 mm × 9 mm Body, Very Thin Quad
(CP-56-7)
Dimensions shown in millimeters
12.20
12.00 SQ
11.80
0.75
0.60
0.45
1.60
MAX
64
49
1
48
PIN 1
10.20
10.00 SQ
9.80
TOP VIEW
(PINS DOWN)
1.45
1.40
1.35
0.20
0.09
7°
3.5°
0°
0.08
COPLANARITY
16
33
0.15
0.05
SEATING
PLANE
17
32
VIEW A
0.27
0.22
0.17
0.50
BSC
LEAD PITCH
VIEW A
ROTATED 90° CCW
COMPLIANT TO JEDEC STANDARDS MS-026-BCD
Figure 86. 64-Lead Low Profile Quad Flat Package [LQFP]
(ST-64-2)
Dimensions shown in millimeters
Rev. B | Page 79 of 80
ADAS1000/ADAS1000-1/ADAS1000-2
Data Sheet
ORDERING GUIDE
Temperature
Range
Package
Model1
Description
Package Description
Option
ST-64-2
ST-64-2
CP-56-7
CP-56-7
CP-56-7
CP-56-7
ST-64-2
ST-64-2
CP-56-7
CP-56-7
ADAS1000BSTZ
ADAS1000BSTZ-RL
ADAS1000BCPZ
5 ECG Channels, Pace Algorithm, Respiration Circuit
5 ECG Channels, Pace Algorithm, Respiration Circuit
5 ECG Channels, Pace Algorithm, Respiration Circuit
5 ECG Channels, Pace Algorithm, Respiration Circuit
5 ECG Channels
−40°C to +85°C 64-Lead LQFP
−40°C to +85°C 64-Lead LQFP
−40°C to +85°C 56-Lead LFCSP_VQ
−40°C to +85°C 56-Lead LFCSP_VQ
−40°C to +85°C 56-Lead LFCSP_VQ
−40°C to +85°C 56-Lead LFCSP_VQ
−40°C to +85°C 64-Lead LQFP
−40°C to +85°C 64-Lead LQFP
−40°C to +85°C 56-Lead LFCSP_VQ
−40°C to +85°C 56-Lead LFCSP_VQ
Evaluation Kit2
ADAS1000BCPZ-RL
ADAS1000-1BCPZ
ADAS1000-1BCPZ-RL
ADAS1000-2BSTZ
ADAS1000-2BSTZ-RL
ADAS1000-2BCPZ
ADAS1000-2BCPZ-RL
EVAL-ADAS1000SDZ
EVAL-SDP-CB1Z
5 ECG Channels
Companion for Gang Mode
Companion for Gang Mode
Companion for Gang Mode
Companion for Gang Mode
ADAS1000 Evaluation Board
System Demonstration Board (SDP), used as a controller
board for data transfer via USB interface to PC
Controller Board3
1 Z = RoHS Compliant Part.
2 This evaluation kit consists of ADAS1000BSTZ × 2 for up to 12-lead configuration. Because the ADAS1000 contains all features, it is the evaluation vehicle for all
ADAS1000 variants.
3 This board allows a PC to control and communicate with all Analog Devices evaluation boards ending in the SD designator.
©2012–2014 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D09660-0-6/14(B)
Rev. B | Page 80 of 80
相关型号：
ADAS1000-4BCPZ
Low Power, 3-Electrode Electrocardiogram (ECG) Analog Front End with respiration measurement and pace detection
ADI
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