MAX1153 [MAXIM]
Stand-Alone, 10-Channel, 10-Bit System Monitors with Internal Temperature Sensor and VDD Monitor; 单机， 10通道， 10位系统监视器，内置温度传感器和VDD监视器
| 型号： | MAX1153 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Stand-Alone, 10-Channel, 10-Bit System Monitors with Internal Temperature Sensor and VDD Monitor |
| 文件： | 总29页 (文件大小：479K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2839; Rev 0; 4/03
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
General Description
Features
o Monitor 10 Signals Without Processor
The MAX1153/MAX1154 are stand-alone, 10-channel (8
external, 2 internal) 10-bit system monitor ADCs with
internal reference. A programmable single-ended/dif-
ferential mux accepts voltage and remote-diode tem-
perature-sensor inputs. These devices independently
monitor the input channels without microprocessor
interaction and generate an interrupt when any variable
exceeds user-defined limits. The MAX1153/MAX1154
configure both high and low limits, as well as the num-
ber of fault cycles allowed, before generating an inter-
rupt. These ADCs can also perform recursive data
averaging for noise reduction. Programmable wait inter-
vals between conversion sequences allow the selection
of the sample rate.
Intervention
o Eight External Channels Programmable as
Temperature or Voltage Monitors
o Intelligent Circuitry for Reliable Autonomous
Measurement
Programmable Digital Averaging Filter
Programmable Fault Counter
o Precision Measurements
10-Bit Resolution
0ꢀ. ꢁSB IꢂꢁL 0ꢀ. ꢁSB Dꢂꢁ
0ꢀꢃ.5C Temperature Accuracy ꢄtypꢅ
o Flexible
Automatic Channel Scan Sequencer with
Programmable Intervals
Programmable Inputs: Single Ended/DifferentialL
Voltage/Temperature
At the maximum sampling rate of 94ksps (auto mode,
single channel enabled), the MAX1153 consumes only
5mW (1.7mA at 3V). AutoShutdownTM reduces supply
current to 190µA at 2ksps and to less than 8µA at 50sps.
Programmable Wait State
Stand-alone operation, combined with ease of use in a
small package (16-pin TSSOP), makes the MAX1153/
MAX1154 ideal for multichannel system-monitoring
applications. Low power consumption also makes
these devices a good fit for hand-held and battery-pow-
ered applications.
o Internal 2ꢀ.V/4ꢀ096V Reference
ꢄMAX11.3/MAX11.4ꢅ
o Remote Temperature Sensing Up to 10m
ꢄDifferential Modeꢅ
o Single 3V or .V Supply Operation
o Small 16-Pin TSSOP Package
Ordering Information
Applications
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
16 TSSOP
System Supervision
Remote Telecom Networks
Server Farms
MAX1153AEUE*
MAX1153BEUE
MAX1154AEUE*
MAX1154BEUE
16 TSSOP
16 TSSOP
Remote Data Loggers
16 TSSOP
*Future product—contact factory for availability.
Selector Guide
Pin Configuration
TEMP
SUPPLY
TOP VIEW
PART
INL (LSB)
ERROR (5C) VOLTAGE (V)
AIN0
CS
1
2
3
4
5
6
7
8
16
15
0.5
0.5
0.5
0.5
1.0
3.0
1.0
2.5
MAX1153AEUE*
MAX1153BEUE
MAX1154AEUE*
MAX1154BEUE
2.7 to 3.6
2.7 to 3.6
4.5 to 5.5
4.5 to 5.5
AIN1
AIN2
AIN3
AIN4
AIN5
AIN6
AIN7
SCLK
14 DIN
13
MAX1153
MAX1154
V
DD
12 GND
11 DOUT
10 INT
*Future product—contact factory for availability.
9
REF
Typical Application Circuit appears at end of data sheet.
TSSOP
AutoShutdown is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
ABSOLUTE MAXIMUM RATINGS
V
to GND .............................................................-0.3V to +6V
Continuous Power Dissipation (T = +70°C)
A
DD
Analog Inputs to GND (AIN0–AIN7, REF) ... -0.3V to (V + 0.3V)
16-Pin TSSOP (derate 8.7mW/°C above +70°C) .........696mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
DD
Digital Inputs to GND (DIN, SCLK, CS) .... -0.3V to (V
Digital Outputs to GND (DOUT, INT) ........ -0.3V to (V
Digital Outputs Sink Current ............................................. 25mA
Maximum Current into Any Pin .......................................... 50mA
+ 0.3V)
+ 0.3V)
DD
DD
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
= +2.7V to +±.6V (MAX115±), V
= +4.5V to +5.5V (MAX1154), V
= +2.5V (MAX115±), V = +4.096V (MAX1154), f
REF SCLK
DD
DD
REF
= 10MHz (50% duty cycle), T = T
to T
, unless otherwise noted. Typical values are at T = +25°C.)
MAX A
A
MIN
PARAMETER
DC ACCURACY
Resolution
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
RES
INL
10
Bits
LSB
Grade A
Grade B
0.5
0.5
0.5
1.0
1.0
2.0
Integral Nonlinearity (Note 1)
Differential Nonlinearity
Offset Error
DNL
No missing codes overtemperature
LSB
LSB
External reference
Internal reference
LSB
Gain Error (Note 2)
%FSR
ppm/°C
Offset Error Tempco
±5
±2
External reference
Internal reference
Gain and Temperature Coefficient
ppm/°C
±±0
0.1
Channel-to-Channel Offset Matching
LSB
%
V
DD
Monitor Accuracy
Internal reference
±2.5
DYNAMIC ACCURACY
(10kHz sine-wave input, 2.5V
(MAX115±), 4.096V (MAX1154), 64ksps, f
P-P SCLK
= 10MHz, bipolar input mode)
P-P
Signal-to-Noise Plus Distortion
Total Harmonic Distortion
Spurious-Free Dynamic Range
Full-Power Bandwidth
SINAD
70
-76
72
dB
dB
THD
Up to the 5th harmonic
SFDR
dB
-±dB point
1
MHz
kHz
Full Linear Bandwidth
S / (N + D) > 68dB
100
CONVERSION RATE
Voltage measurement, all ref modes
Temp-sensor ref modes 01, 10
Temp-sensor ref mode 00
10.6
11.7
50.7
80
Conversion Time (Note ±)
t
46
µs
CONV
7±
Single-Channel Throughput
Power-Up Time
Manual trigger, voltage measurement
Internal reference (Note 4)
70
ksps
µs
t
40
45
PU
ANALOG INPUT (AIN0–AIN7)
Unipolar, single-ended, or differential inputs
Bipolar, differential inputs
0
V
REF
Input Voltage Range (Note 5)
Common-Mode Range
V
V
-V
/ 2
+V
/ 2
REF
REF
Differentially configured inputs
0
V
DD
2
_______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
ELECTRICAL CHARACTERISTICS (continued)
(V
= +2.7V to +±.6V (MAX115±), V
= +4.5V to +5.5V (MAX1154), V
= +2.5V (MAX115±), V = +4.096V (MAX1154), f
REF SCLK
DD
DD
REF
= 10MHz (50% duty cycle), T = T
to T
, unless otherwise noted. Typical values are at T = +25°C.)
MAX A
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Differentially configured inputs,
Common-Mode Rejection
90
dB
V
= 0 to V
DD
CM
Input Leakage Current
On-/off- leakage, V = 0 or V
IN
±0.1
18
±1
µA
pF
DD
Input Capacitance
(Note 6)
TEMPERATURE MEASUREMENTS
T
T
T
T
T
T
T
T
T
T
T
= -20°C to +85°C
= -40°C to +85°C
= +25°C
±0.5
±0.75
±0.±
±1.2
±0.7
±1.2
±0.7
±2
±1.0
±1.5
A
A
A
A
A
A
A
A
A
A
A
Grade A
MAX115±
MAX1154
Internal Sensor Measurement Error
(Note 7)
= -40°C to +85°C
= +25°C
±±.0
±2.5
°C
Grade B
MAX115±
= -40°C to +85°C
= +25°C
Grade B
MAX1154
= -40°C to +85°C
= +25°C
Differential
±1
External Sensor Measurement
Error (Note 8)
°C
°C
= -40°C to +85°C
= +25°C
±5
Single ended
±2
Differentially configured inputs and internal
sensor
0.1
Temperature Measurement Noise
Single-ended configured, external sensor
0.5
0.5
4
Temperature Resolution
°C/LSB
Low
External Sensor Bias Current
µA
High
66
Differentially configured inputs and internal
sensor
0.±
0.1
Power-Supply Rejection
PSR
°C/V
Single-ended configured, external sensor
INTERNAL REFERENCE
MAX115±
MAX1154
Grade A
Grade B
2.456
2.456
2.500
4.096
8
2.544
4.168
REF Output Voltage
V
V
REF
REF Temperature Coefficient
REF Output Resistance
REF Output Noise
TC
ppm/°C
kΩ
REF
±0
7
MAX115±
MAX1154
MAX115±
MAX1154
200
160
-70
-70
µV
RMS
dB
V
-50
-50
REF Power-Supply Rejection
µA
EXTERNAL REFERENCE
REF Input Voltage Range
V
1.0
V
+ 0.05
40
V
REF
DD
V
V
= +2.5V; f
= +2.5V; f
= 94ksps
= 0
15
REF
REF
SAMPLE
REF Input Current
I
µA
REF
±1
SAMPLE
_______________________________________________________________________________________
3
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
ELECTRICAL CHARACTERISTICS (continued)
(V
= +2.7V to +±.6V (MAX115±), V
= +4.5V to +5.5V (MAX1154), V
= +2.5V (MAX115±), V = +4.096V (MAX1154), f
REF SCLK
DD
DD
REF
= 10MHz (50% duty cycle), T = T
to T
, unless otherwise noted. Typical values are at T = +25°C.)
MAX A
A
MIN
PARAMETER
DIGITAL INPUTS (SCLK, DIN, CS)
Input Voltage Low
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
V
+ 0.±
DD
V
V
IL
Input Voltage High
V
V
+ 0.7
DD
IH
Input Hysteresis
V
200
2
mV
µA
pF
HYST
Input Leakage Current
Input Capacitance
I
IN
V
= 0 or V
DD
±10
IN
C
IN
DIGITAL OUTPUTS (INT, DOUT)
I
I
I
I
= 8mA, DOUT
= 2mA, INT
0.5
0.5
SINK
Output Voltage Low
Output Voltage High
V
V
V
OL
SINK
= 8mA, DOUT
= 2mA, INT
V
V
+ 0.5
+ 0.5
SOURCE
SOURCE
DD
DD
V
OH
Tri-State Leakage Current
Tri-State Output Capacitance
POWER REQUIREMENTS
I
CS = V
CS = V
±10
µA
pF
L
DD
DD
C
5
OUT
MAX115±
2.7
2.7
±.6
5.5
±.±
2.9
2.2
5.0
4.0
±.0
Positive Supply Voltage
V
V
DD
MAX1154
MAX115± internal reference (Note 9)
MAX115± internal reference (Note 10)
MAX115± internal reference (Note 10)
MAX1154 internal reference (Note 9)
MAX1154 internal reference (Note 10)
MAX1154 internal reference (Note 10)
Both internal reference, mode 01 (Note 11)
mA
Supply Current
I
DD
8
µA
nA
µA
MAX115±
Full power-down state
MAX1154
480
860
±0.4
Full Power-Down Supply Current
Power-Supply Rejection Ratio
I
SHDN
PSRR
Analog inputs at full scale (Note 12)
±1.6
4
_______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
TIMING CHARACTERISTICS
(V = +2.7V to +±.6V (MAX115±), V = +4.5V to +5.5V (MAX1154), T = T
to T , unless otherwise noted.) (Figures 1, 2, and 4)
MAX
DD
DD
A
MIN
PARAMETER
SYMBOL
CONDITIONS
MIN
100
45
45
25
0
TYP
MAX
UNITS
ns
SCLK Clock Period
t
CP
CH
SCLK Pulse Width High Time
SCLK Pulse Width Low Time
DIN to SCLK Setup Time
DIN to SCLK Hold Time
CS Fall to SCLK Rise Setup
SCLK Rise to CS Rise Hold
SCLK Fall to DOUT Valid
CS Rise to DOUT Disable
CS Fall to DOUT Enable
CS Pulse Width High
t
ns
t
t
ns
CL
DS
DH
ns
t
ns
t
25
50
ns
CSS
CSH
DOV
DOD
t
ns
t
C = ±0pF
50
40
40
ns
L
t
C = ±0pF
L
ns
t
C = ±0pF
L
ns
DOE
CSW
t
50
ns
Note 1: Relative accuracy is the deviation of the analog value at any code from its theoretical value after the gain and offset errors
have been calibrated.
Note 2: Offset nulled.
Note 3: In reference mode 00, the reference system powers up for each temperature measurement. In reference mode 01, the ref-
erence system powers up once per sequence of channels scanned. If a sample wait <80µs is programmed, the reference
system is on all the time. In reference mode 10, the reference system is on all the time (see Table 7).
Note 4: No external capacitor on REF.
Note 5: The operational input voltage range for each individual input of a differentially configured pair (AIN0–AIN7) is from GND to
V
DD
The operational input voltage difference is from -V
/2 to +V
REF
/2.
REF
.
Note 6: See Figure ± and the Sampling Error vs. Input Source Impedance graph in the Typical Operating Characteristics section.
Note 7: Grade A tested at +10°C and +55°C. -20°C to +85°C and -40°C to +85°C specifications guaranteed by design. Grade B
tested at +25°C. T
to T
specification guaranteed by design.
MIN
MAX
Note 8: External temperature measurement mode using an MMBT±904 (Diodes Inc.) as a sensor. External temperature sensing
from -40°C to +85°C; MAX115±/MAX1154 held at +25°C.
Note 9: Performing eight single-ended external channels’ temperature measurements, an internal temperature measurement, and
an internal V
measurement with no sample wait results in a conversion rate of 2ksps per channel.
DD
Note 10: Performing eight single-ended voltage measurements, an internal temperature measurement, and an internal V
surement with no sample wait results in a conversion rate of 7ksps per channel.
mea-
mea-
DD
Note 11: Performing eight single-ended voltage measurements, an internal temperature measurement, and an internal V
surement with maximum sample wait results in a conversion rate of ±ksps per channel.
DD
Note 12: Defined as the shift in the code boundary as a result of supply voltage change. V
= min to max; full-scale input, mea-
DD
sured using external reference.
_______________________________________________________________________________________
5
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Typical Operating Characteristics
(V
= +±V, V
= 2.5V (MAX115±); V
= 5V, V
= 4.096V (MAX1154); f
= 10MHz, C
= 0.1µF, T = +25°C, unless
DD
REF
DD
REF
SCLK
REF A
otherwise noted.)
INTEGRAL NONLINEARITY
vs. DIGITAL OUTPUT CODE
DIFFERENTIAL NONLINEARITY
vs. DIGITAL OUTPUT CODE
INTERNAL REFERENCE VOLTAGE
vs. SUPPLY VOLTAGE
0.50
0.40
0.30
0.20
0.10
0
0.50
0.40
0.30
0.20
0.10
0
2.510
2.509
2.508
2.507
2.506
2.505
2.504
2.503
2.502
2.501
2.500
MAX1153
-0.10
-0.20
-0.30
-0.40
-0.50
-0.10
-0.20
-0.30
-0.40
-0.50
0
0
256
512
768
1024
256
512
768
1024
2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
SUPPLY VOLTAGE (V)
OUTPUT CODE
OUTPUT CODE
REFERENCE VOLTAGE
vs. TEMPERATURE
INTERNAL REFERENCE VOLTAGE
vs. SUPPLY VOLTAGE
2.505
2.504
2.503
2.502
2.501
2.500
2.499
2.498
2.497
2.496
2.495
4.085
4.083
4.081
4.079
4.077
4.075
MAX1154
MAX1153
GRADE B
GRADE A
20
-40
-20
0
40
60
80
4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
REFERENCE VOLTAGE
vs. TEMPERATURE
SUPPLY CURRENT
vs. SAMPLE RATE
4.0900
4.0875
10
1
INTERNAL REFERENCE
(MODE 01) MAX1153
MAX1154
9 TEMPERATURE
CHANNELS AND 1
VOLTAGE CHANNEL
4.0850
4.0825
4.0800
4.0775
GRADE A
(V /2)
DD
0.1
9 VOLTAGE
CHANNELS AND
1 TEMPERATURE
CHANNEL
4.0750
4.0725
4.0700
0.01
0.001
GRADE B
1 VOLTAGE CHANNEL
(V /2)
DD
-40
-20
0
20
40
60
80
0.001
0.01
0.1
1
10
100
TEMPERATURE (°C)
SAMPLE RATE (kHz)
6
_______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Typical Operating Characteristics (continued)
(V
= +±V, V
= 2.5V (MAX115±); V
= 5V, V
= 4.096V (MAX1154); f
= 10MHz, C
= 0.1µF, T = +25°C, unless
DD
REF
DD
REF
SCLK
REF
A
otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY CURRENT
vs. SAMPLE RATE
10
1
EXTERNAL REFERENCE (MODE 00)
9 TEMPERATURE CHANNELS
INTERNAL REFERENCE (MODE 01)
9 TEMPERATURE CHANNELS
INTERNAL REFERENCE
4.3
3.9
3.5
3.1
2.7
2.3
1.9
1.5
4.2
3.8
3.4
3.0
2.6
2.2
1.8
1.4
1.0
(MODE 01) MAX1154
AND 1 VOLTAGE CHANNEL (V /2)
AND 1 VOLTAGE CHANNEL (V /2)
DD
DD
9 TEMPERATURE
CHANNELS AND 1
VOLTAGE CHANNEL
9 VOLTAGE
9 VOLTAGE CHANNELS AND
1 TEMPERATURE CHANNEL
CHANNELS AND
1 TEMPERATURE
CHANNEL
(V /2)
DD
0.1
9 VOLTAGE
CHANNELS AND
1 TEMPERATURE
CHANNEL
0.01
0.001
1 VOLTAGE CHANNEL
(V /2)
DD
1 VOLTAGE
CHANNEL (V /2)
1 VOLTAGE CHANNEL
(V /2)
DD
DD
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
SUPPLY VOLTAGE (V)
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
SUPPLY VOLTAGE (V)
0.001
0.01
0.1
1
10
100
SAMPLE RATE (kHz)
SUPPLY CURRENT
vs. TEMPERATURE
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
SUPPLY CURRENT
vs. TEMPERATURE
2.6
2.5
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.6
5.0
4.5
4.0
3.5
3.0
2.5
2.0
INTERNAL REFERENCE (MODE 01) MAX1154
700
600
500
400
300
200
100
9 TEMPERATURE CHANNELS AND
1 VOLTAGE CHANNEL (V /2)
DD
9 TEMPERATURE CHANNELS AND
1 VOLTAGE CHANNEL (V /2)
DD
MAX1154
9 VOLTAGE CHANNELS AND
1 TEMPERATURE CHANNEL
9 VOLTAGE CHANNELS AND
1 TEMPERATURE CHANNEL
MAX1153
1 VOLTAGE CHANNEL (V /2)
DD
1 VOLTAGE CHANNEL (V /2)
DD
INTERNAL REFERENCE (MODE 01) MAX1153
-40 -25 -10 20 35 50 65 80
TEMPERATURE (°C)
5
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
SUPPLY VOLTAGE (V)
-40 -25 -10
5
20 35 50 65 80
TEMPERATURE (°C)
GAIN AND OFFSET ERROR
vs. SUPPLY VOLTAGE
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
GAIN ERROR vs. TEMPERATURE
0.25
0.20
0.15
0.10
0.05
0
1.00
UNIPOLAR
BIPOLAR DIFFERENTIAL
CONFIGURATION
EXTERNAL REFERENCE
MODE
SINGLE ENDED
700
600
500
400
300
200
100
0
0.80
0.60
0.40
0.20
0
DIFFERENTIAL
CONFIGURATION
EXTERNAL
MAX1154
V
DD
= 5V
OFFSET ERROR
REFERENCE MODE
MAX1153
-0.20
-0.40
-0.60
-0.80
-1.00
MAX1154
UNIPOLAR SINGLE-ENDED
CONFIGURATION
EXTERNAL REFERENCE MODE
GAIN ERROR
MAX1153
= 3V
-0.05
-0.10
V
DD
-40 -25 -10
5
20 35 50 65 80
-40 -25 -10
5
20 35 50 65 80
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
TEMPERATURE (°C)
_______________________________________________________________________________________
7
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Typical Operating Characteristics (continued)
(V
= +±V, V
= 2.5V (MAX115±); V
= 5V, V
= 4.096V (MAX1154); f
= 10MHz, C
= 0.1µF, T = +25°C, unless
DD
REF
DD
REF
SCLK
REF A
otherwise noted.)
INTERNAL TEMPERATURE SENSOR
TEMPERATURE ERROR
EXTERNAL TEMPERATURE SENSOR
TEMPERATURE ERROR
OFFSET ERROR vs. TEMPERATURE
0.25
0.20
0.15
0.10
0.05
0
1.00
0.80
0.60
0.40
0.20
0
2.00
UNIPOLAR
UNIPOLAR SINGLE-ENDED
CONFIGURATION
EXTERNAL REFERENCE
MODE
MAX1153/MAX1154
MAX1153/MAX1154
DIFFERENTIAL
CONFIGURATION
EXTERNAL
1.60
1.20
0.80
0.40
0
GRADE B INTERNAL
SENSOR
EXTERNAL SENSOR,
DIFFERENTIAL INPUT
REFERENCE MODE
BIPOLAR DIFFERENTIAL
CONFIGURATION
EXTERNAL REFERENCE
MODE
-0.05
-0.10
-0.15
-0.20
-0.25
-0.20
-0.40
-0.60
-0.80
-1.00
-0.40
-0.80
-1.20
-1.60
-2.00
GRADE A INTERNAL
SENSOR
EXTERNAL SENSOR,
SINGLE-ENDED INPUT
-40 -25 -10
5
20 35 50 65 80
-40
-20
0
20
40
60
80
-40
-20 20
0
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
SAMPLING ERROR
vs. INPUT SOURCE IMPEDANCE
TEMPERATURE ERROR vs. INTERCONNECT
CAPACITANCE (EXTERNAL SENSOR)
1
0
1
0
-1
-2
-3
-4
-5
-6
-1
-2
-3
-4
-5
10
100
1000
10,000
100
1000
SOURCE IMPEDANCE (Ω)
INTERCONNECT CAPACITANCE (pF)
TURN ON THERMAL TRANSIENT,
CONTINUOUS CONVERSION
V
= 3.0V
DD
0.625
IN A TSSOP SOCKET
0.500
0.375
0.250
0.125
0
SOLDER ON A 2in X 2in PWB
IN AN OIL BATH
EXTERNAL BJT
-0.125
0
5
10
15
20
25
30
TIME (s)
8
_______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Block Diagram
V
DD
REF
REFERENCE
INPUT CHANNEL REGISTER
INPUT CONFIGURATION REGISTER
STEP-UP REGISTER
TEMP
SENSOR
MAX1153
MAX1154
ALARM REGISTER
12-BIT
ADC WITH
T/H
AIN1
AIN2
AIN3
AIN4
AIN5
AIN6
AIN7
DOUT
DIN
MUX
SERIAL
INTERFACE
SCLK
CS
SCAN
AND
CONVERSION
CONTROL
AVERAGING
DIGITAL
COMPARATOR
POWER
GOOD
INT
POR
INTERNAL TEMP
V
/2
DD
AIN0
AIN1
AIN2
AIN3
AIN4
AIN5
AIN6
AIN7
ACCUMULATOR ACCUMULATOR ACCUMULATOR ACCUMULATOR ACCUMULATOR ACCUMULATOR ACCUMULATOR ACCUMULATOR ACCUMULATOR ACCUMULATOR
UPPER
THRESHOLD
UPPER
THRESHOLD
UPPER
THRESHOLD
UPPER
THRESHOLD
UPPER
THRESHOLD
UPPER
THRESHOLD
UPPER
THRESHOLD
UPPER
THRESHOLD
UPPER
THRESHOLD
UPPER
THRESHOLD
LOWER
THRESHOLD
LOWER
THRESHOLD
LOWER
THRESHOLD
LOWER
THRESHOLD
LOWER
THRESHOLD
LOWER
THRESHOLD
LOWER
THRESHOLD
LOWER
THRESHOLD
LOWER
THRESHOLD
LOWER
THRESHOLD
CHANNEL
CHANNEL
CHANNEL
CHANNEL
CHANNEL
CHANNEL
CHANNEL
CHANNEL
CHANNEL
CHANNEL
CONFIGURATION CONFIGURATION CONFIGURATION CONFIGURATION CONFIGURATION CONFIGURATION CONFIGURATION CONFIGURATION CONFIGURATION CONFIGURATION
Pin Description
PIN NAME
FUNCTION
1
2
±
4
5
6
7
8
AIN0 Analog Voltage Input/Temperature Input Channel 0 or Positive Differential Input Relative to AIN1
AIN1 Analog Voltage Input/Temperature Input Channel 1 or Negative Differential Input Relative to AIN0
AIN2 Analog Voltage Input/Temperature Input Channel 2 or Positive Differential Input Relative to AIN±
AIN± Analog Voltage Input/Temperature Input Channel ± or Negative Differential Input Relative to AIN2
AIN4 Analog Voltage Input/Temperature Input Channel 4 or Positive Differential Input Relative to AIN5
AIN5 Analog Voltage Input/Temperature Input Channel 5 or Negative Differential Input Relative to AIN4
AIN6 Analog Voltage Input/Temperature Input Channel 6 or Positive Differential Input Relative to AIN7
AIN7 Analog Voltage Input/Temperature Input Channel 7 or Negative Differential Input Relative to AIN6
Positive Reference Input in External Mode. Bypass REF with a 0.1µF capacitor to GND when in external mode.
When using the internal reference, REF must be left open.
9
REF
10
INT
Interrupt Output. Push-pull or open drain with selectable polarity. See Table 9 and the INT Interrupt Output section.
11 DOUT Serial Data Output. DOUT transitions on the falling edge of SCLK. High impedance when CS is at logic high.
12
1±
14
GND Ground
Positive Power Supply. Bypass with a 0.1µF capacitor to GND.
DIN Serial Data Input. DIN data is latched into the serial interface on the rising edge of the SCLK.
V
DD
15 SCLK Serial Clock Input. Clocks data in and out of the serial interface (duty cycle must be 40% to 60%).
Active-Low Chip-Select Input. When CS is low, the serial interface is enabled. When CS is high, DOUT is high
impedance, and the serial interface resets.
16
CS
_______________________________________________________________________________________
9
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
V
DD
V
DD
100µA
100µA
DOUT
DOUT
DOUT
DOUT
100µA
C
LOAD
= 100pF
C
= 100pF
LOAD
100µA
C
= 100pF
C
= 100pF
LOAD
LOAD
DGND
a) V TO HIGH-Z
DGND
b) V TO HIGH-Z
DGND
a) V TO V
DGND
b) HIGH-Z TO V AND V TO V
OL
OH
OL
OL
OH
OL
OH
Figure 1. Load Circuits for DOUT Enable Time and SCLK to
DOUT Delay Time
Figure 2. Load Circuit for DOUT Disable Time
alarm condition. If desired, the device can be pro-
grammed to average the results of many measurements
before comparing to the threshold value. This reduces
the sensitivity to external noise in the measured signal.
In addition, the user can set the number of times the
threshold is exceeded (fault cycles) before generating
an interrupt. This feature reduces falsely triggered
alarms caused by undesired, random spurious impulses.
Detailed Description
The MAX115±/MAX1154 are precision-monitoring inte-
grated circuit systems specifically intended for stand-
alone operation. They can monitor diverse types of
inputs, such as those from temperature sensors and
voltage signals from pressure, vibration, and accelera-
tion sensors, and digitize these input signals. The digi-
tal values are then compared to preprogrammed
thresholds and, if the thresholds are exceeded, the
processor is alerted by an interrupt signal. No interac-
tion by the CPU or microcontroller (µC) is required until
one of the programmed limits is exceeded (Figures ±
and 4).
When the fault cycle criterion is exceeded, an alarm
condition is created. The device writes the fault condi-
tion into the alarm register to indicate the alarmed input
channel.
Converter Operation
The MAX115±/MAX1154 ADCs use a fully differential
successive-approximation register (SAR) conversion
technique and an on-chip track-and-hold (T/H) block to
convert temperature and voltage signals into a 10-bit
digital result. Both single-ended and differential config-
urations are supported with a unipolar signal range for
single-ended mode and bipolar or unipolar ranges for
differential mode. Figure 5 shows the equivalent input
circuit for the MAX115±/MAX1154. Configure the input
channels according to Tables 5 and 6 (see the Input
Configuration Register section).
Voltages on all the inputs are converted to 10-bit values
sequentially and stored in the current data registers.
Note that eight of these inputs are external and two are
internal. One of the internal inputs monitors the V
DD
voltage supply, while the other monitors the internal IC
temperature. AIN0 to AIN7 can be configured as either
single ended (default) or differential. In addition, these
inputs can be configured for single-ended or differen-
tial temperature measurements. In the temperature
configuration, the device provides the proper bias nec-
essary to measure temperature with a diode-connected
transistor sensor. The user enables which inputs are
measured (both external and internal) and sets the
delay between each sequence of measurements dur-
ing the initial setup of the device.
In single-ended mode, the positive input (IN+) is con-
nected to the selected input channel and the negative
input (IN-) is connected to GND. In differential mode,
IN+ and IN- are selected from the following pairs:
AIN0/AIN1, AIN2/AIN±, AIN4/AIN5, and AIN6/AIN7.
Once initiated, voltage conversions require 10.6µs (typ)
to complete.
The values stored in the current data registers are com-
pared to the user-preprogrammed values in the thresh-
old registers (upper and lower thresholds) and, if
exceeded, activate the interrupt output and generate an
10 ______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
V
DD
INPUT REGISTERS 0–10
CURRENT DATA
AIN 0
AIN 1
AIN 2
AIN 3
AIN 4
AIN 5
AIN 6
AIN 7
UPPER THRESHOLD
LOWER THRESHOLD
# FAULT CYCLES
AVERAGE
12-BIT
ADC WITH T/H
DIGITAL
COMPARATOR
INT
MUX
CONFIGURATION/
STATUS
REGISTERS
SCAN AND
CONVERSION
CONTROL
DIN
SERIAL
INTERFACE
DOUT
SCLK
CS
TEMP
SENSE
Figure 3. Simplified Alarm Block Diagram of the MAX1153/MAX1154
During the acquisition interval, IN+ and IN- charge both
a positive (CHOLDP) and a negative (CHOLDN) sam-
pling capacitor. After completing the acquisition inter-
val, the T/H switches open, storing an accurate sample
of the differential voltage between IN+ and IN-. This
charge is then transferred to the ADC and converted.
Finally, the conversion result is transferred to the cur-
rent data register.
Input Bandwidth
The ADC’s input tracking circuitry has a 1MHz small-
signal bandwidth. To avoid high-frequency signals
aliasing into the frequency band of interest, anti-alias
prefiltering of the input signals is recommended.
Analog Input Protection
Internal protection diodes, which clamp the analog
inputs to V
and GND, allow the channel input pins to
DD
Temperature conversions require 46µs (typ) and mea-
sure the difference between two sequential voltage
measurements (see the Temperature Measurement
section for a detailed description).
swing from (GND - 0.±V) to (V
+ 0.±V) without dam-
DD
age. However, for accurate conversions near full scale,
the inputs must not exceed V by more than 50mV or
DD
be lower than GND by 50mV. If the analog input range
must exceed 50mV beyond the supplies, limit the input
current.
Fully Differential Track/Hold (T/H)
The T/H acquisition interval begins with the rising edge
of CS (for manually triggered conversions) and is inter-
nally timed to 1.5µs (typ). The accuracy of the input sig-
nal sample is a function of the input signal’s source
impedance and the T/H’s capacitance. In order to
achieve adequate settling of the T/H, limit the signal
source impedance to a maximum of 1kΩ.
Single Ended/Differential
The MAX115±/MAX1154 use a fully differential ADC for
all conversions. Through the input configuration regis-
ter, the analog inputs can be configured for either dif-
ferential or single-ended conversions. When sampling
signal sources close to the MAX115±/MAX1154, single-
ended conversion is generally sufficient. Single-ended
conversions use only one analog input per signal
source, internally referenced to GND.
______________________________________________________________________________________ 11
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
INCREMENT
CHANNEL
COUNTER
IS CHANNEL
NO
ENABLED?
YES
SAMPLE
CHANNEL
CONVERT
CHANNEL
AVERAGE
CONVERTED
CHANNEL DATA
IS
SAME FAULT
AS PREVIOUS?
INCREMENT
FAULT COUNTER
AVG DATA
> UPPER?
YES
YES
NO
NO
YES
RESET FAULT
COUNTER
IS
AVG DATA
< LOWER?
NO
IS
FAULT CNT
>
FAULT REG?
NO
YES
SET ALARM
REGISTER
Figure 4. Alarm Flowchart
12 ______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
V
V
DD
DD
T
T
T
CHOLD
CHOLDP
CHOLDN
8-TO-1
DIFFERENTIAL
MUX
8-TO-1
DIFFERENTIAL
MUX
ADC
ADC
H
H
T
T
T
H
H
H
TEMP
TEMP
V
AZ
V
AZ
SINGLE-ENDED INPUT EQUIVALENT INPUT CIRCUIT
DIFFERENTIAL INPUT EQUIVALENT INPUT CIRCUIT
Figure 5. Single-Ended/Differential Input Equivalent Input Circuit
In differential mode, the T/H samples the difference
between two analog inputs, eliminating common-mode
DC offsets and noise. See the Input Configuration
Register section and Tables 5 and 6 for more details on
configuring the analog inputs.
Digital Interface
The MAX115±/MAX1154 digital interface consists of
five signals: CS, SCLK, DIN, DOUT, and INT. CS,
SCLK, DIN, and DOUT comprise an SPI™-compatible
serial interface (see the Serial Digital Interface section).
INT is an independent output that provides an indica-
tion that an alarm has occurred in the system (see the
INT Interrupt Output section).
Unipolar/Bipolar
When performing differential conversions, the input
configuration register (Tables 5 and 6) also selects
between unipolar and bipolar operation. Unipolar mode
Serial Digital Interface
The MAX115±/MAX1154 feature a serial interface com-
patible with SPI, QSPI™, and MICROWIRE™ devices.
For SPI/QSPI, ensure that the CPU serial interface runs
in master mode so it generates the serial clock signal.
sets the differential input range from 0 to V
A nega-
REF.
tive differential analog input in unipolar mode causes
the digital output code to be zero. Selecting bipolar
mode sets the differential input range to
V /2. The
REF
digital output code is straight binary in unipolar mode
and two’s complement in bipolar mode (see the
Transfer Function section).
Select a serial clock frequency of 10MHz or less, and
set clock polarity (CPOL) and phase (CPHA) in the µP
control registers to the same value, one or zero. The
MAX115±/MAX1154 support operation with SCLK idling
high or low, and thus operate with CPOL = CPHA = 0 or
CPOL = CPHA = 1.
In single-ended mode, the MAX115±/MAX1154 always
operate in unipolar mode. The analog inputs are inter-
nally referenced to GND with a full-scale input range
from 0 to V
REF.
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
______________________________________________________________________________________ 13
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
CS
t
CSW
t
t
t
CH
CSH
CSS
t
CP
t
CL
SCLK
DIN
t
DS
t
DH
t
t
DOD
DOV
t
DOE
DOUT
Figure 6. Detailed Serial Interface Timing Diagram
Clock pulses on SCLK shift data into DIN on the rising
edge of the SCLK and out of DOUT on the falling edge
of SCLK.
Output Data Format
Output data from the MAX115±/MAX1154 is clocked
onto DOUT on the falling edge of SCLK. Single-ended
and unipolar differential measurements are output in
straight binary MSB first, with two 8-bytes-per-conver-
sion result, with 2 sub-bits and the last 4 bits padded
with zeros. For temperature and bipolar differential volt-
age measurements, the output is two’s complement
binary in the same 2-byte format. The MSB of the out-
put data from a read command transitions at DOUT
after the falling edge of the 8th SCLK clock pulse fol-
lowing the CS high-to-low transition. Table 2 shows the
number of bytes to be read from DOUT for a given read
command.
Data transfers require a logic low on CS. A high-to-low
transition of CS marks the beginning of a data transfer. A
logic high on CS at any time resets the serial interface.
See Figure 6 and the Timing Characteristics table for
detailed serial-interface timing information.
Input Data Format
Serial communications always begin with an 8-bit com-
mand word, serially loaded from DIN. A high-to-low
transition on CS initiates the data input operation. The
command word and the subsequent data bytes (for
write operations) are clocked from DIN into the
MAX115±/MAX1154 on the rising edges of SCLK. The
first rising edge on SCLK, after CS goes low, clocks in
the MSB of the command word (see the Command
Word section). The next seven rising edges on SCLK
complete the loading of the command word into the
internal command register. After the 8-bit command
word is entered, transfer 0 to 20 bytes of data, depend-
ing on the command. Table 2 shows the number of
data bytes for each command.
Command Word
The command word (Table 1) controls all serial com-
munications and configuration of the MAX115±/
MAX1154, providing access to the 44 on-chip registers.
The first 4 MSBs of the command word specify the
command (Table 2), while the last 4 bits provide
address information.
The first rising edge on SCLK, after CS goes low, trans-
fers the command word MSB into DIN. The next seven
rising edges on SCLK shift the remaining 7 bits into the
internal command register (see the Serial Digital
Interface section).
Table 1. Command Word
B7 (MSB)
B6
B5
B4
B3
B2
B1
B0 (LSB)
Command B± Command B2 Command B1 Command B0
Address B±
Address B2
Address B1
Address B0
14 ______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Table 2. Command Description
DATA BYTES AFTER
COMMAND WORD
COMMAND
WORD
COMMAND DESCRIPTION
BYTES TO BYTES FROM
DIN
DOUT
0000####
0001xxxx
0010####
0011####
0100####
0101xxxx
0110xxxx
0111xxxx
1000####
1001xxxx
1010####
1011xxxx
1100####
1101xxxx
1110xxxx
1111xxxx
0
0
±
Manually Trigged Conversion
0
Read Alarm Register
0
2
Read Current Data Register for Selected Channel
Read Current Data Register for All Channels
Read Configuration Register for Selected Channel
Read Global Configuration Registers
Reserved
0
20
5
0
0
5
N/A
0
N/A
0
Reset
0
0
Clear Alarm/Fault for Selected Channels
Clear Alarm/Fault for All Channels
Write Current Data Register for Selected Channel
Write Current Data Registers for All Channels
Write Configuration Registers for Selected Channel
Write Global Configuration Registers
Reserved
0
0
2
0
20
5
0
0
5
0
N/A
N/A
N/A
N/A
Reserved
#### = Channel address code, see Table ±.
xxxx = These bits are ignored for this command.
Manually Triggered Conversion
Table 3. Channel Address
(Command Code = 0000)
Before beginning a manual conversion, ensure the
scan mode bit in the setup register is zero, because a
logic 1 disables manual conversions. The address bits
in a Manually Triggered Conversion command select
the input channel for conversion (see Table ±). When
performing a differential conversion, use the even chan-
nel address (AIN0, AIN2, AIN4, AIN6); the command is
ignored if odd channel addresses (AIN1, AIN±, AIN5,
AIN7) are used for a differential conversion.
ADDRESS IN COMMAND
INPUT
Internal temperature
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
V
DD
AIN0
AIN1
AIN2
AIN±
AIN4
After issuing a Manually Triggered Conversion com-
mand, bring CS high to begin the conversion. To obtain
a correct conversion result, CS must remain high for a
period longer than the reference power-up time (if in
power-down mode) plus the conversion time for the
selected channel-configured conversion type (voltage
or temperature). The conversion’s result can then be
read at DOUT by issuing a Read Current Data Register
for Selected Channel command, addressing the con-
verted channel. See Table ± for channel addresses.
AIN5
AIN6
AIN7
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
______________________________________________________________________________________ 15
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Read Alarm Register
(Command Code 0001)
The Read Alarm Register command, 0001, outputs the
current status of the alarm register (see Table 11). The
address bits in this command are ignored. The alarm
register is 24 bits long and outputs in ± bytes. Table 12
illustrates the encoding of the alarm register.
Read Current Data Register for All
Channels (Command Code 0011)
The Read Current Data Registers for All Channels com-
mand, 0011, outputs the data in the current data regis-
ters of all 10 channels, starting with the internal
temperature sensor, then the V
monitor, followed by
DD
AIN0 to AIN7. The address bits following this command
are ignored. It takes 20 bytes to read all of the 10 chan-
nels’ current data registers.
After receiving an interrupt, read the alarm register to
determine the source of the interrupt (see the Alarm
Register section).
Read Configuration Register for Selected
Channel (Command Code 0100)
Read Current Data Register for Selected
Channel (Command Code 0010)
The Read Configuration Register for Selected Channel
command, 0100, outputs the configuration data of the
channel selected by the address bits (see Table ±).
The first register that shifts out is the upper threshold
register (2 bytes), followed by the lower threshold regis-
ter (2 bytes), ending with the channel configuration reg-
ister (1 byte), all MSB first. It takes 5 bytes to read all
three registers. See the Channel Registers section for
more details.
The Read Current Data Register for Selected Channel
command, 0010, outputs the data in the current data
register of the selected channel. The address bits fol-
lowing this command select the input channel to be
read (see Table ±). The current data register is a 10-bit
register. It takes 2 bytes to read its value. See the
Output Data Format and Current Data Registers sec-
tions for more details. See Table ± for channel address-
es. Also, see Figure 7.
CS
SCLK
DIN
C3 C2 C1 C0 A3 A2 A1 A0
DOUT
D11
D10 D9 D8 D7 D6 D5 D4
D3
D2 D1 D0
Figure 7. Serial Register Read Timing
16 ______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Read Global Configuration Register
(Command Code 0101)
Clear Alarm Register for All Channels
(Command Code 1001)
The Read Global Configuration Register command,
0101, outputs the global configuration registers. The
address bits following this command are ignored. When
the MAX115±/MAX1154 receive a Read Global
Configuration Register command, they output 5 bytes
of data: 2 bytes from the channel enable register, 2
bytes from the input configuration register, and 1 byte
from the setup register, all MSB first. See the Global
Configuration Registers section for more details.
The Clear Alarm Register for All Channels command,
1001, clears the entire alarm register and resets the
fault counters for the internal TEMP sensor, the V
DD
monitor, and the AIN0–AIN7 channels. The address bits
in the command are ignored. See the Alarm Register
section for more details.
Write Current Data Register for Selected
Channel (Command Code 1010)
The Write Current Data Register for Selected Channel
command, 1010, writes to the addressed channel’s cur-
rent data register. This command sets an initial condi-
tion when using the averaging filter option (see the
Averaging section). This command can also be used
for testing the thresholds, fault counters, and alarm
functions (see Figure 8). See Table ± for channel
addresses.
RESET (Command Code 0111)
The RESET command, 0111, resets the device. This
command returns the MAX115±/MAX1154 to their
power-on reset state, placing the device into shutdown
mode. The address bits in the command are ignored.
See the Power-Up/Reset Defaults Summary section for
more details.
Clear Channel Alarm for Selected Channel
(Command Code 1000)
The Clear Channel Alarm command, 1000, clears the
alarm bits in the alarm register and resets the fault
counter for the addressed channel. See the Alarm
Register section for more details. See Table ± for chan-
nel addresses.
Write Current Data Register for All
Channels (Command Code 1011)
The Write Current Data Register for All Channels com-
mand, 1011, writes to the current data registers of all
channels sequentially, starting with the internal temper-
ature sensor, then the V
monitor, followed by chan-
DD
nels AIN0 to AIN7. The address bits are ignored. Use
this command for testing and setting initial conditions
when using the averaging filter option (see the
Averaging section).
CS
SCLK
DIN
C3 C2 C1 C0 A3 A2 A1 A0
D11 D10 D9 D8 D7 D6 D5 D4
D3 D2 D1 D0
DOUT
Figure 8. Serial Register Write Timing
______________________________________________________________________________________ 17
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Write-Selected Channel Configuration
Registers (Command Code 1100)
Channel-Enable Register
The channel-enable register (Table 4) controls which
channels are converted while in automatic scan mode.
The register contents are ignored for manual conver-
sion commands. Each input channel has a correspond-
ing bit in the channel-enable register. A logic high
enables the corresponding analog input channel for
conversion, while a logic low disables it. In differential
configuration, the bits for odd channels are ignored. At
power-up and after a RESET command, the register
contents default to 111111111111b (all channels
enabled).
The Write-Selected Channel Configuration Register com-
mand, 1100, writes to the three channel configuration
registers for the addressed channel (see Table ±). The
first register to be written is the upper threshold (2 bytes),
followed by the lower threshold (2 bytes), ending with the
channel configuration register (1 byte), all MSB first.
Writing to the configuration registers resets the alarm reg-
ister bits and the fault counters for the addressed chan-
nel. See the Channel Registers section for more details.
Write Global Configuration Registers
(Command Code 1101)
Input Configuration Register
The input configuration register (Table 5) stores the
configuration code for each channel as a ±-bit per
channel-pair code (see Table 6), selecting from five
input signal configurations: single-ended unipolar volt-
age, single-ended temperature, differential unipolar
voltage, differential bipolar voltage, and differential
temperature. Table 5 shows the input configuration reg-
ister format, and Table 6 shows the ±-bit encoding for
channel configuration. At power-up and after a RESET
command, the register contents defaults to
000000000000b (all inputs single ended).
The Write Global Configuration Registers command,
1101, writes to three registers: the channel-enable reg-
ister (2 bytes), the input configuration register (2 bytes),
and the setup register (1 byte). The command address
bits are ignored. See the Global Configuration
Registers section for more details.
Global Configuration Registers
The global configuration registers consist of the chan-
nel-enable register, the input configuration register, and
the setup register. These registers hold configuration
data common to all channels.
Table 4. Channel-Enable Register Format
B11
(MSB)
B0
(LSB)
B10
B9
B8
B7
B6
B5
B4
B3
B2
B1
TEMP
VDD
AIN0
AIN1
AIN2
AIN±
AIN4
AIN5
AIN6
AIN7
Res
Res
Table 5. Input Configuration Register Format
B11
B0
(LSB)
B10
B9
B8
B7
B6
B5
B4
B3
B2
B1
(MSB)
AIN0 and AIN1 configuration
AIN2 and AIN± configuration
AIN4 and AIN5 configuration
AIN6 and AIN7 configuration
Table 6. Channel Configuration Coding (3 Bits/Channel Pair)
CODE
000
001
010
011
100
101
110
111
AIN0, AIN2, AIN4, AIN6 CONFIGURATION
Single-ended input (power-up state)
Single-ended input
AIN1, AIN3, AIN5, AIN7 CONFIGURATION
Single-ended input (power-up state)
Single-ended, external temperature sensor input
Single-ended input
Single-ended, external temperature sensor input
Single-ended, external temperature sensor input
Differential unipolar encoded, positive input
Differential bipolar encoded, positive input
Differential external temperature sensor, positive input
Reserved
Single-ended, external temperature sensor input
Differential unipolar encoded, negative input
Differential bipolar encoded, negative input
Differential external temperature sensor, negative input
Reserved
18 ______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
±) Sequence to the next-enabled channel until all
enabled channels have been converted.
Setup Register
The 8-bit setup register (Table 7) holds configuration
data common to all input channels. At power-up and
after a RESET command, this register defaults to
00000000b.
4) Wait the sample wait time, and enter internal refer-
ence power-down mode if this period is greater
than 80µs.
5) Repeat the above steps.
Setup Register: Sample Wait Bits (B7, B6, B5)
These ± bits in the setup register (Table 8) set the wait
time between conversion scans. The following are
examples of how the MAX115±/MAX1154 begin a sam-
ple sequence (see the Setup Register: Reference
Selection Bits (B1/B0) section).
Operating in reference mode 10 (internal reference for
all conversions, continuously powered up):
1) Convert the first-enabled channel.
2) Sequence to the next-enabled channel until all
enabled channels have been converted.
Operating in reference mode 00 (external reference for
voltage conversions, internal reference for temperature
conversions):
±) Wait the sample wait time.
4) Repeat the procedure.
1) Convert the first-enabled channel. If this channel is
a temperature measurement, power up the internal
reference (this takes 20µs for each enabled tem-
perature measurement in reference mode 00).
Use the sample wait feature to reduce supply current
when measuring slow-changing analog signals. This
power savings occurs when reference mode 00 or 01 is
used in combination with wait times longer than 80µs.
With reference mode 10 or wait times of less than 80µs,
the internal reference system remains powered up, mini-
mizing any power savings. See the Computing Data
Throughput section. Table 8 shows the B7, B6, B5 wait
time encoding.
2) Sequence to the next-enabled channel until all
channels have been converted.
±) Wait the sample wait period.
4) Repeat the procedure.
Operating in reference mode 01 (internal reference for all
conversions, can be powered down between scans):
Setup Register: Interrupt Control (B4, B3)
Bits B± and B4 in the setup register configure INT and
how it responds to an alarm event (see the Alarm
Register section). Table 9 shows the available INT
options.
1) Power up the internal reference, if powered down
(this takes 40µs).
2) Convert the first-enabled channel, starting with the
internal temperature sensor, if enabled.
Table 7. Setup Register Format
B7 (MSB)
B6
B5
B4
B3
B2
B1
B0 (LSB)
Interrupt
active
Interrupt
polarity
Scan
mode
Reference
source B1
Reference
source B2
Sample wait bits
Table 8. Wait Time Encoding
Table 9. Interrupt Control
B7, B6, B5
000
WAIT TIME (ms)
BIT
BIT FUNCTION
STATE
INT OPERATION
0
1
0
Driven high or low at all times
001
0.080
0.±95
1.±10
4.970
19.600
78.200
±12.000
Output
driver type
B4
B±
010
High-Z when inactive, driven (high
or low) when active
011
1
0
Active high, inactive = low or high -Z
Active low, inactive = high or high -Z
100
Output
polarity
101
110
111
______________________________________________________________________________________ 19
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Setup Register: Scan Mode Bit (B2)
The scan mode bit selects between automatic scan-
ning and manual conversion mode.
Setup Register: Reference Selection Bits (B1, B0)
The MAX115±/MAX1154 can be used with an internal
or external reference. Select between internal and
external reference modes through bits B1 and B0 of the
setup register (see Table 10).
When set (B2 = 1), the MAX115±/MAX1154 enter auto-
matic scanning mode and convert every enabled chan-
nel starting with the internal temperature sensor,
Alarm Register
followed by the V
AIN0 to AIN7.
monitor, then sequencing through
DD
The alarm register (Table 11) holds the current alarm sta-
tus for all of the monitored signals. This 24-bit register
can only be read and cleared. The alarm register has 2
bits for each external input channel, 2 for the onboard
After converting all the enabled channels, the
MAX115±/MAX1154 enter a wait state set by the sam-
ple wait bits in the setup register. After completing the
sample wait time, the scan cycle repeats.
temperature sensor, and 2 for the V
monitor (see
DD
Table 12). At power-up, these bits are logic low, indicat-
ing no alarms at any input. When any bit in the alarm reg-
ister is set, INT becomes active and remains active until
all alarm bits are cleared. After a fault counter exceeds
the set threshold, the alarm register bits for that particular
channel are updated to indicate an alarm.
When B2 = 0, the MAX115±/MAX1154 are in manual
mode and convert only the selected channel after
receiving a Manually Triggered Conversion command
(see the Manually Triggered Conversion (Command
Code 0000) section). Whether in automatic scanning
mode or manual mode, a Read Current Data Register
for Selected Channel command outputs the last-com-
pleted conversion result for the addressed channel at
DOUT.
To clear the interrupt, reset the active alarm bit with the
Clear Alarm Register command, Clear Channel Alarm
command, a RESET command, or by writing a new
configuration to the faulting channel. The alarm register
defaults to 000000 hex.
Table 11 illustrates how the alarm register stores the
information on which channel a fault has occurred. The
alarm code for each bit pair is shown in Table 12.
Table 10. Reference Selection
B1 B0
REFERENCE MODE
Channel Registers
Voltage measurements use external reference,
while temperature measurements use the internal
reference. A 20µs reference startup delay is
added prior to each temperature measurement
in this mode. This is the default mode after
power-up and after a software RESET.
Each channel (internal temperature sensor, V
moni-
DD
tor, and AIN0 to AIN7) has registers to hold the conver-
sion result (current data register) and channel-specific
configuration data. The channel-specific configuration
registers include: the upper threshold register, the
lower threshold register, and the channel configuration
register. In differential mode, only the registers for the
even channel of the differential input pair are used. The
channel-specific configuration registers for the odd
channel of a differential channel pair are ignored.
0
0
0
1
All measurements use the internal reference. A
40µs reference startup delay is added prior to
starting the scanning of enabled channels,
allowing the internal reference to stabilize.
Note: For sample wait times less than 80µs, the
reference is continuously powered when in
automatic scan mode.
Table 12. Alarm Register Coding
(2 Bits/Channel)
All measurements use the internal reference. By
selecting this mode, the reference is powered up
immediately when CS goes high after writing this
configuration. Once the reference system is
powered up, no further delay is added.
CODE
00
DESCRIPTION
No alarm (power-up state)
1
1
0
1
01
Input is below lower threshold
Input is above upper threshold
Reserved
10
Reserved.
00
Table 11. Alarm Register Format
B23/B22 B21/B20 B19/B18 B17/B16 B15/B14 B13/B12 B11/B10
TEMP AIN0 AIN1 AIN2 AIN± AIN4
B9/B8
B7/B6
B5/B4
B3/B2
B1/B0
V
AIN5
AIN6
AIN7
Res
Res
DD
20 ______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Table 13. Channel Configuration Register Format
B7 (MSB)
B6
B5
B4
B3
B2
B1
B0 (LSB)
Fault B±
Fault B2
Fault B1
Fault B0
Ave B±
Ave B2
Ave B1
Ave B0
normal range defined by the thresholds, the fault
counter resets. If the next counter finds the input signal
outside the opposite threshold, rather than the previous
one, the fault counter also resets. The fault counter
increments only when counting consecutive faults
exceeding the same threshold (Figure 4).
Table 14. Conversion Average Encoding
CODE
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
N
1, no averaging
2
4
Averaging
The averaging calculated by the data-acquisition algo-
rithm of the MAX115±/MAX1154 improves the input sig-
nal-to-noise ratio (SNR) by reducing the signal
bandwidth digitally. The formula below describes the
filter implemented in the MAX115±/MAX1154:
8
16
±2
64
128
256
current value = [(N - 1) / N] x past value +
[(present value) / N]
where N = number of samples indicated in Table 14.
512
1024
2048
Reserved
Reserved
Reserved
Reserved
The averaging bits (B±–B0) in the channel configuration
register can set the N factor to any value in Table 14.
The output of the filter-running algorithm is continuously
available in the current data register. The starting value
used by the algorithm is the initial state of the current
data register. The current data register is reset to mid-
scale (800 hex) at power-up or after a RESET com-
mand, but it can be loaded with a more appropriate
initial value to improve the filter settling time.
Channel Configuration Register
Each channel has a channel configuration register (Table
1±) defining the number of consecutive faults to be
detected before setting the alarm bits and generating an
interrupt, as well as controlling the digital averaging func-
tion. At power-up and after a RESET command, the regis-
ter defaults to 00 hex (no averaging, alarm on first fault).
At power-up or after a RESET command, the B±–B0
bits of the channel configuration register are set to 0
hex, corresponding to a number of averaged N = 1, no
averaging. See Table 1± and the Write-Selected
Channel Configuration Registers section for program-
ming details. See Table 14 for N encoding.
Fault Bits
The value stored in the fault bits (B7–B4) in the channel
configuration register sets the number of faults that
must occur for that channel before generating an inter-
rupt. Encoding of the fault bits is straight binary with
values 0 to 15. A fault occurs in a channel when the
value in its current data register is outside the range
defined by the channel’s upper and lower threshold
registers. For example, if the number of faults set by the
fault bits is N, an interrupt is generated when the num-
ber of consecutive faults (see following note) reach
(N + 1). The fault bits default to 0 hex at power-up.
As in all digital filters, truncation can be a cause of sig-
nificant errors. In the MAX115±/MAX1154, 24 bits of
precision are maintained in the digital averaging func-
tions, maintaining a worst-case truncation error of well
below an LSB. The worst-case truncation error in the
MAX115±/MAX1154 is given by the following:
N-1
16±84
worst-case truncation error =
LSBs
where N = number of conversions averaged.
Therefore, the worst truncation error when averaging
256 samples is 0.01557 LSBs.
Note: Consecutive faults are those happening in con-
secutive conversion scans for the same channel. If a
fault occurs and the next scan finds the input within the
______________________________________________________________________________________ 21
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
channel are updated to indicate an alarm. When any bit in
the alarm register is set, the INT output becomes active,
and stays active until all alarm bits are cleared. See the
Alarm Register section for more information.
Upper Threshold Register
A conversion result greater than the value stored in the
upper threshold register results in a fault, increasing the
internal fault counter by one. When the fault count
exceeds the value stored in fault bits B7–B4 of the chan-
nel configuration register, the channel’s alarm bits in the
alarm register are set, resulting in an interrupt on INT.
Servicing Interrupts at INT
After detecting an interrupt on INT, the µC’s interrupt
routine should first read the alarm register to find the
source of the alarm and reset the alarm bits by using
any of the methods described in the Alarm Register
section. Then it can continue with any other action
required by the application to react to the alarm.
The upper threshold register data format must be the
same as the input channel. When the input channel is
configured for single-ended or differential unipolar volt-
age measurements, data stored in the upper threshold
register is interpreted as straight binary. For input chan-
nels configured for temperature measurements or as
differential bipolar voltage inputs, the upper threshold
register data is interpreted as two’s complement. Load
the register with ±FF hex to disable upper threshold
faults in unipolar mode, and 1FF hex in temperature or
bipolar mode. The power-up/reset default is FFF hex.
See the Command Word section on how to read/write
to the upper threshold registers.
Note: Multiple alarm conditions can be present. The
INT remains active until all alarm conditions have been
cleared.
Performing Conversions
At power-up or after a RESET command, the
MAX115±/MAX1154 default to shutdown mode with all
channels enabled, set for single-ended voltage mea-
surements, and with the scan mode set to manual. Start
a conversion by issuing a manually triggered conver-
sion command with the address bits of the channel
selected (see the Manual Conversion section for more
details) or by setting automatic scan mode. To place
the MAX115±/MAX1154 in automatic scan mode, set
the scan mode bit B2 in the setup register to logic 1.
Lower Threshold Register
Conversion results lower than the value stored in the
lower threshold register increment the internal fault
counter. Considerations about channel configuration
register fault bits B7–B4, INT interrupts, and data for-
mat are the same as for the upper threshold register.
Set the register to 000 hex to disable lower threshold
faults in unipolar mode, or to 200 hex in temperature or
bipolar mode. The power-up/reset default is 000 hex.
See the Command Word section on how to read/write
to the lower threshold registers.
In automatic scan mode, the MAX115±/MAX1154 con-
vert all enabled channels starting with the internal tem-
perature sensor, followed by the V
monitor, then by
DD
AIN0 to AIN7. As the scan sequence progresses, the
analog inputs are converted and the resulting values
are stored for each channel into its current data regis-
ter. Once the scan cycle completes, the MAX115±/
MAX1154 wait a period determined by the sample wait
bits (B7, B6, B5) in the setup register and then repeat
the scan cycle.
Current Data Registers
The current data register holds the last conversion
result or the digitally averaged result, when enabled
(see the Averaging section). The current data registers
default to 800 hex at power-up/reset and can be read
from and written to through the serial interface. See the
Command Word section on how to read/write to the
current data registers.
After configuring the MAX115±/MAX1154 with automat-
ic scan mode enabled, the devices do not require any
intervention from the system µC until an alarm is trig-
gered. All conversion and monitoring functions can
continue running indefinitely.
INT Interrupt Output
INT provides an indication that an alarm has occurred
in the system. It can be programmed (see Table 9) to
operate as a push-pull digital output or as an open-
drain output (requiring either a pullup or a pulldown
resistor) for wired-OR interrupt lines. Bits B± and B4 in
the setup register configure INT and determine its
response to an alarm event.
Manual Conversion
In manual mode (scan mode bit in the setup register
set to zero, the default after power-up/reset), the
MAX115±/MAX1154 convert individual channels with
the Manually Triggered Conversion command. Assuming
that, either by power-up/RESET defaults or by previous
initialization, the channel to be addressed is both
enabled and configured for the type of signal to be
acquired (voltage/temperature, single ended/differen-
tial, or unipolar/bipolar), carry out the following steps to
When an internal fault counter exceeds the threshold
stored in the fault bits (B7–B4) of the corresponding chan-
nel configuration register, the alarm bits for that particular
22 ______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
execute a manual conversion. See Figure 9 for manual
conversion timing:
Monitoring V
DD
This internal acquisition channel samples and converts
the supply voltage, V
.
DD
1) Disable autoscan (set up register scan mode bit to
zero), if necessary.
V
value can be calculated from the digitized data
DD
with the following equation:
2) Pull CS low.
±) Initiate a conversion by issuing a Manually
Triggered Conversion command (0000, followed by
the address bits of the channel to be converted).
V
1024
REF
VDD = 2 x (current_data_register_content) x
4) Pull CS high to start the conversion.
The reference voltage must be larger than 1/2V
for
DD
5) Maintain a logic high on CS to allow for reference
power-up (if the reference mode requires it) and
conversion time.
the operation to work properly. V
10.6µs (typ) per measurement.
monitoring requires
DD
Temperature Measurement
The MAX115±/MAX1154 perform temperature measure-
ment by measuring the voltage across a diode-con-
nected transistor at two different current levels. The
following equation illustrates the algorithm used for
temperature calculations:
6) Pull CS low.
7) Issue a Read Current Data Register for Selected-
Channel command (0010, followed by the same
address of the channel in the Manually Triggered
Conversion command).
Voltage Measurements
q
k
Every voltage measurement (internal V
or external
DD
input channel) requires 10.6µs to complete. If the inter-
nal reference needs to power up (reference mode =
01), an additional 40µs is required every time the
MAX115±/MAX1154 come out of automatic shutdown
mode after a sample wait period greater than 80µs.
temperature = (V
− V
) x
HIGH
LOW
I
High
n x ln
I
LOW
t
PU+CONV
CS
SCLK
C3
DIN
C2 C1 C0 A3 A2 A1 A0
C3 C2 C1 C0 A3 A2 A1 A0
DOUT
Figure 9. Manual Conversion Timing Without Reading Data
______________________________________________________________________________________ 23
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
where:
the reference mode, and starts the automatic scan
mode. See the Write Global Configuration Registers
Command section, Table 2, and Tables 5–10.
V
HIGH
(I
HIGH
= sensor-diode voltage with high current flowing
)
Immediately after the global configuration register is
loaded, the MAX115±/MAX1154 begin to update the
current data registers. Acquire conversion data from
the MAX115±/MAX1154 by issuing a command to read
a specific channel with the Read Current Data Register
for Selected Channel command. Read all current data
register at once with the Read Current Data Registers
for All Channels command.
V
(I
= sensor-diode voltage with low current flowing
LOW
)
LOW
q = charge of electron = 1.602 ✕ 10-19 coulombs
k = Boltzman constant = 1.±8 ✕ 10-2± J/K
n = ideality factor (slightly greater than 1)
The temperature measurement process is fully auto-
mated in the MAX115±/MAX1154. All steps are
sequenced and executed by the MAX115±/MAX1154
each time an input channel (or an input channel pair)
configured for temperature measurement is scanned.
For more complex applications, the monitoring and
interrupt generation features of the MAX115±/MAX1154
require a second step of initialization. Each enabled
channel to be monitored requires configuration using a
Write Configuration Register for Selected Channel com-
mand. Each command is a 5-byte write that sets the
upper and lower fault thresholds, the number of faults for
an alarm before an interrupt is generated, and an aver-
age algorithm parameter if the application requires input
signal filtering.
The resulting 10-bit, two’s complement number repre-
sents the sensor temperature in degrees Celsius, with
1 LSB = +0.5°C.
The MAX115±/MAX1154 support both single-ended
and differential temperature measurements.
Applications Information
Setting Up the
MAX1153/MAX1154 Subsystem
Applications can read the current data registers and
respond to interrupts signaled by the INT output (see
the Servicing Interrupts at INT section).
The MAX115±/MAX1154 are autonomous subsystems,
requiring only initialization to scan, convert, and monitor
the voltage signals or the temperature sensors con-
nected to their input channels.
All the MAX115±/MAX1154 registers can be verified by
reading back written data, including the configuration
registers. This feature is useful for development and
testing (see Table 2).
For simple applications, using any number of the input
channels and any combination of voltage/temperature
and unipolar/differential, with no interrupt generation
required, use the following intitialization procedure:
Power-Up/Reset Defaults Summary
Setup Register Power-Up/Reset Defaults
At initial power-up or after a RESET command, the
setup register resets to 00 hex. Consequently, the
MAX115±/MAX1154 are configured as follows:
•
Issue a Write Global Configuration Registers com-
mand. This is a single, 5-byte write operation that
configures the input channels, enables the chan-
nels to be used, sets the sample wait time between
scans, configures the interrupt output INT, selects
•
•
Sample wait time is 0µs.
INT output is open drain and outputs an active-low
signal to signify an alarm.
Table 15. Power-Up/Reset Defaults Summary
REGISTER
Setup
BIT RANGE
B0 to B7
B0 to B11
B0 to B11
B0 to B2±
B0 to B7
B0 to B9
B0 to B9
B0 to B9
POWER-UP/RESET STATE
COMMENT
See Setup Register Power-Up/Reset Defaults
All channels (int/ext) enabled
All single-ended voltage inputs
No alarms set
All 0s
All 1s
All 0s
All 0s
All 0s
All 1s
All 0s
200hex
Channel enable
Input configuration
Alarm register
Channel configuration
Upper threshold
Lower threshold
Current data registers
Faults = 0, no averaging
All upper thresholds max range
All lower thresholds min range
Set at midrange
24 ______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
•
•
Manual conversion mode
ple wait period (if sample wait time > 80µs), and no
power-up time in reference mode 10.
External reference for voltage measurements
The sampling period is calculated as follows:
Channel Enable Register Power-Up/Reset Defaults
t
sw
= (t ) + (N )t
+ (N )t
+ t
pu
v conv[volt]
t conv[temp] wait
At power-on or after a RESET command, the channel
enable register resets to FF hex, enabling all channels:
the internal temperature sensor, the V
AIN0–AIN7.
where:
monitor, and
DD
t
t
t
= all channels scan sampling period
= reference power-up time
sw
pu
Input Configuration Register
Power-Up/Reset Defaults
= voltage-configured channel conversion time
conv[volt]
N = number of voltage-configured channels
v
At power-on or after a RESET command, the input con-
figuration register resets to 00 hex, configuring
AIN0–AIN7 for single-ended voltage measurement.
t
= temperature-configured channel conver-
conv[temp]
sion time
N = number of temperature-configured channels
t
Alarm Register Power-Up/Reset Defaults
At power-on or after a RESET command, the alarm reg-
ister is reset to 000000 hex, indicating that no alarm
condition exists.
t
= sample wait time
wait
The terms in the previous equation are determined as
shown by the number of enabled channels, the input
channel configuration (voltage vs. temperature), the
sample wait time, and the reference mode. The follow-
ing calculation shows a numeric example:
Current Data Register Power-Up/Reset Defaults
At power-on or after a RESET command, each chan-
nel’s current data register is reset to 800 hex.
t
sw
= 40µs + 8 x 10.6µs + 2 x 46µs + ±95µs = 611.8µs
Upper Threshold Register Power-Up/Reset Defaults
At power-on or after a RESET command, each chan-
nel's upper threshold register is reset to FFF hex. This
state effectively disables the upper threshold.
•
40µs is the time required for the reference to power-
up (reference mode = 00) every time the
MAX115±/MAX1154 come out of automatic shut-
down mode after a sample wait period.
Lower Threshold Register Power-Up/Reset Defaults
At power-on or after a RESET command, each chan-
nel's lower threshold register is reset to 000 hex. This
state effectively disables the lower threshold.
•
•
•
8 x 10.6µs is the time required for seven channels
configured for voltage measurement and the VDD
monitor.
2 x 46µs is the time required for temperature mea-
surement (46µs for each temperature measurement
(internal or external)).
Channel Configuration Register
Power-Up/Reset Defaults
At power-on or after a RESET command, each chan-
nel's configuration register is reset to 000 hex, which
configures the fault bits to cause an alarm to occur on
the first overrange or underrange condition and dis-
ables averaging.
±95µs is the sample wait time, set by bits B5, B6,
B7 of the setup register (see Tables 7 and 8).
The MAX115±/MAX1154 use an internal clock for all
conversions. The serial interface clock does not affect
conversion time.
Performing eight single-ended remote channels tem-
perature measurements, an internal temperature mea-
Computing Data Throughput
The MAX115±/MAX1154 throughput rate depends on
the number of enabled channels, their configuration
(temperature or voltage), and the reference mode.
Voltage measurements require 10.6µs (typ) to com-
plete, and temperature measurements require 46µs.
surement, and an internal V
measurement with a
DD
sample wait time of zero results in an average conver-
sion rate of 24ksps or 2.4ksps per channel.
Performing eight single-ended voltage measurements,
an internal temperature measurement, and an internal
Channel pairs configured for differential measurements
count as only one for throughput computation.
V
DD
measurement with sample wait time of zero results
in an average conversion rate of 70ksps or 7ksps per
channel.
The reference system takes 20µs to power up in refer-
ence mode 00 prior to each temperature measurement,
40µs to power up in reference mode 01 after each sam-
______________________________________________________________________________________ 25
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Single-Ended Temperature Measurement
Connect the anode of a diode-connected transistor to
the input channel and the cathode to ground. Choose
ground connections for sensors away from high-current
return paths to avoid the introduction of errors caused by
voltage drops in the board/system ground, which is the
main drawback for single-ended measurements.
Practical options for better accuracy are the use of a
star-configured subsystem ground or a signal ground
plane; to isolate the anode sensor connection trace away
from board and system noise sources; or to shield it with
ground lines and ground planes (when available) to pre-
vent accuracy degradation in the temperature measure-
ments caused by magnetic/electric noise induction.
Automatic Reference Shutdown
The MAX115±/MAX1154 enter an automatic shutdown
mode when in reference mode 00 or when the sample
wait is greater than 80µs in reference mode 01. Using
either of these reference modes and a sample wait
period as long as the application allows results in the
lowest power consumption.
Temperature Measurement
The MAX115±/MAX1154 support both single-ended
and differential temperature measurements. The design
decision between the two types of measurements
depends on the desired level of accuracy and on type
and/or number of temperature sensors. The superior
common-mode rejection and lower noise of the differ-
ential mode reduces measurement errors and provides
higher accuracy, while single-ended measurements
require a lower number of connections, resulting in a
simpler implementation and a higher number of moni-
tored points for each MAX115±/MAX1154.
Configure the MAX115±/MAX1154 input used for single-
ended temperature measurement in the input configura-
tion register (see Tables 9 and 10) and enable the
analog input in the channel-enable register (see Table 4).
Remote Temperature Sensor Selection
Temperature-sensing accuracy depends on having a
good-quality, diode-connected, small-signal transistor
as a sensor. Accuracy has been experimentally verified
for 2N±904-type devices. The transistor must be a
small-signal type with low base resistance. Tight speci-
fications for forward current gain (+50 to +150, for
example) indicate that the manufacturer has good
process controls and that the devices have consistent
Differential Temperature Measurement
Connect the anode of a diode-connected transistor to
the even input channel and the cathode to the odd
input channel of an input pair configured for differential
temperature measurement (AIN0/AIN1, AIN2/AIN±,
AIN4/AIN5, or AIN6/AIN7). Run the two sensor connec-
tion lines parallel to each other with minimum spacing.
This improves temperature measurement accuracy by
minimizing the differential noise between the two lines,
since they have equal exposure to most sources of
noise. For further improved noise rejection, shield the
two sensor connections by running them between
ground planes, when available.
V
characteristics. CPU on-board sensors and other
BE
ICs’ on-board temperature-sensing devices can also
be used (see Table 16 for recommended devices).
OUTPUT CODE
FULL-SCALE
Configure the MAX115±/MAX1154 inputs for differential
temperature measurement in the input configuration
register (see Tables 9 and 10) and enable the even
channel number in the channel enable register (see
Table 4).
11....111
11....110
11....101
TRANSITION
FS = V
ZS = 0
REF
Table 16. Remote Sensor Transistor
Manufacturers
V
REF
MANUFACTURER
MODEL NUMBER
CMPT±904
1 LSB =
00....011
00....010
00....001
00....000
1024
Central Semiconductor (USA)
Fairchild Semiconductors (USA) MMBT±904
Motorola (USA)
MMBT±904
SST±904
0
0
1
2
3
FS
FS = 3/2 LSB
INPUT VOLTAGE (LSB)
Rohm Semiconductor (Japan)
Siemens (Germany)
Zetex (England)
SMB±904
FMMT±904CT-ND
MMBT±904
Figure 10. Unipolar Transfer Function, Full Scale (FS) = V
REF
Diodes Inc.
26 ______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
OUTPUT CODE
FS =
OUTPUT CODE
V
REF
2
011....111
011....111
011....110
011....110
000....010
ZS = 0
-V
REF
-FS =
2
V
000....010
REF
1 LSB =
000....001
000....000
111....111
111....110
111....101
000....001
000....000
111....111
111....110
111....101
1024
100....001
100....000
100....001
100....000
0
-FS
+FS - 1 LSB
0
-256°C
+255.5°C
INPUT VOLTAGE (LSB)
TEMPERATURE °C
Figure 12. Temperature Transfer Function
Figure 11. Bipolar Transfer Function, Full Scale ( FS) =
V /2
REF
Transfer Function
Figure 10 shows the nominal transfer function for sin-
gle-ended or differential unipolar configured inputs,
Figure 11 illustrates the transfer function for differential
bipolar conversions, and Figure 12 shows temperature
conversions. Code transitions occur halfway between
successive-integer LSB values. Output coding is bina-
ry, with 1 LSB = 2.44mV (MAX115±) or 4mV (MAX1154)
for unipolar and bipolar operation, and 1 LSB = +0.5°C
(MAX115±/MAX1154) for temperature measurements.
Definitions
Integral Nonlinearity
Integral nonlinearity is the deviation of the values on the
actual transfer function from a straight line. This straight
line can be either a best-straight-line fit or a line drawn
between the end points of the transfer function, once off-
set and gain errors have been corrected. The static lineari-
ty parameters for the MAX115±/MAX1154 are measured
using the end-point-fit method. INL is specified as the
maximum deviation in LSBs.
For unipolar operation, the 0 code level transition is at
[1/2(V
/ 1024)].
REF
Differential Nonlinearity (DNL)
Differential nonlinearity is the difference between an
actual step width and the ideal value of 1 LSB. A DNL
error specification of less than 1 LSB guarantees no
missing codes and a monotonic transfer function.
The FFF hex level transition is at [1022.5(V
/ 1024)].
REF
1 LSB = V
/ 1024.
REF
Layout, Grounding, and Bypassing
For best performance, use PC boards. Do not use wire-
wrap boards. Board layout should ensure that digital
and analog signal lines are separated from each other.
Do not run analog and digital (especially clock) signals
parallel to one another or run digital lines underneath
the MAX115±/MAX1154 package. High-frequency
Offset Error
The offset error is the difference between the ideal and
the actual analog input value at the first transition of the
ADC, usually from digital code 0 to code 1 for straight
binary output. For the MAX115±/MAX1154, the transi-
tion between code 0 and code 1 should occur at an
input voltage of 1/2 LSB, or 1.22mV for the MAX115±
and 2mV for the MAX1154.
noise in the V
power supply can affect the
DD
MAX115±/MAX1154 performance. Bypass the V
ply with a 0.1µF capacitor from V
sup-
DD
to GND close to
DD
the V
pin. Minimize capacitor lead lengths for best
DD
supply-noise rejection. If the power supply is very
noisy, connect a 10Ω resistor in series with the supply
to improve power-supply filtering.
______________________________________________________________________________________ 27
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Gain Error
The gain error is the difference between the ideal and
actual value of the analog input difference between the
first and last transitions of the ADC output. The first
transition is from digital code 0 to code 1, and the last
from code (2N-2) to code (2N-1), where N = number of
ADC bits for straight binary output code. For the
MAX115±/MAX1154, the ideal difference in the input
voltage between code transitions 0 to 1 and code tran-
sitions 1022 to 102± is 1022 x LSB. For the MAX115±,
this is 2.5V - 2 x LSB = 2.495117, and for the MAX1154,
this is 4.096V - 2 x LSB = 4.088. Gain error is a DC
specification, usually normalized to the FS ideal analog
value and given in percent of FSR or ppm.
Signal-to-Noise Plus Distortion
Signal-to-noise plus distortion (SINAD) is the ratio of the
fundamental input frequency’s RMS amplitude to the
RMS equivalent of all other ADC output signals:
SINAD (dB) = 20 x log (Signal
/ Noise
)
RMS
RMS
There are other noise sources besides quantization
noise, including thermal noise, reference noise, clock
jitter, etc. Therefore, SINAD is calculated by taking the
ratio of the full-scale signal to the RMS noise, which
includes all spectral components minus the fundamen-
tal and the first five harmonics.
Total Harmonic Distortion (THD)
Total harmonic distortion (THD) is the ratio of the RMS
sum of the first five harmonics of the input signal to the
fundamental itself. This is expressed as:
Signal-to-Noise Ratio
For a waveform perfectly reconstructed from digital
samples, signal-to-noise ratio (SNR) is the ratio of the
full-scale analog input (RMS value) to the RMS quantiza-
tion error (residual error). The ideal theoretical minimum
analog-to-digital noise is caused by quantization error
only, results directly from the ADC’s resolution (N bits),
and can be calculated with the following equation:
2
2
2
2
V
+ V
+ V
+ V
5
(
)
2
±
4
THD = 20 x log
V
1
where V is the fundamental RMS value, and V
1
2
through V are the RMS values of the 2nd- through 5th-
5
order harmonics, respectively.
SNR = (6.02 x N + 1.76)dB
There are other noise sources besides quantization
noise, including thermal noise, reference noise, clock
jitter, etc. Therefore, SNR is calculated by taking the
ratio of the RMS signal to the RMS noise, which
includes all spectral components minus the fundamen-
tal, the first five harmonics, and the DC offset.
Power-Supply Rejection
Power-supply rejection is the ratio between the change
in the ADC full-scale output to the change in power-
supply voltage when the power-supply voltage is varied
from its nominal value. It is specified in V/V or µV/V.
28 ______________________________________________________________________________________
Stand-Alone, 10-Channel, 10-Bit System Monitors
with Internal Temperature Sensor and V Monitor
DD
Typical Operating Circuit
POWER SUPPLY
µC
+V
-5V
+5V
+3V
V
DD
VREF
REFERENCE
GLOBAL REGISTERS
TEMP
SENSOR
INT
SPI
INTERFACE
SPI I/F
AIN0
AIN1
AIN2
AIN3
AIN4
AIN5
AIN6
AIN7
ADC
DIGITAL BLOCK
48V
MUX
MAX1153
MAX1154
CHANNEL REGISTERS
GND
REMOTE TEMP
Chip Information
TRANSISTOR COUNT: 89,47±
PROCESS: 0.6µm BiCMOS
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 29
© 200± Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
相关型号：
MAX1153-MAX1154
Stand-Alone, 10-Channel, 10-Bit System Monitors with Internal Temperature Sensor and VDD Monitor
MAXIM
MAX1153AEUE
Stand-Alone, 10-Channel, 10-Bit System Monitors with Internal Temperature Sensor and VDD Monitor
MAXIM
MAX1153AEUE+
Serial Switch/Digital Sensor, 10 Bit(s), 0.75Cel, Rectangular, Surface Mount, TSSOP-16
MAXIM
MAX1153AEUE-T
Serial Switch/Digital Sensor, 10 Bit(s), 0.75Cel, Rectangular, Surface Mount, TSSOP-16
MAXIM
MAX1153BEUE
Stand-Alone, 10-Channel, 10-Bit System Monitors with Internal Temperature Sensor and VDD Monitor
MAXIM
MAX1153BEUE+
Stand-Alone, 10-Channel, 10-Bit System Monitors with Internal Temperature Sensor and VDD Monitor
MAXIM
MAX1153BEUE-T
Serial Switch/Digital Sensor, 10 Bit(s), 0.75Cel, Rectangular, Surface Mount, TSSOP-16
MAXIM
MAX1153_10
Stand-Alone, 10-Channel, 10-Bit System Monitors with Internal Temperature Sensor and VDD Monitor
MAXIM
MAX1153|MAX1154
Stand-Alone. 10-Channel. 10-Bit System Monitors with Internal Temperature Sensor and VDD Monitor
MAXIM
MAX1154
Stand-Alone, 10-Channel, 10-Bit System Monitors with Internal Temperature Sensor and VDD Monitor
MAXIM
MAX1154AEUE
Stand-Alone, 10-Channel, 10-Bit System Monitors with Internal Temperature Sensor and VDD Monitor
MAXIM
©2020 ICPDF网 联系我们和版权申明