ZMD31015AF-T [IDT]
Sensor/Transducer;型号: | ZMD31015AF-T |
厂家: | INTEGRATED DEVICE TECHNOLOGY |
描述: | Sensor/Transducer |
文件: | 总46页 (文件大小:295K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
Features
The RBicdLite™ is adjustable to nearly all piezo-resis-
tive bridge sensors. Measured and corrected bridge
values are provided at the SIG™ pin, which can be
configured as an analog voltage output or as a one-
wire serial digital output.
•
•
•
Digital compensation of sensor offset, sensitivity,
temperature drift and non-linearity
Programmable analog gain and digital gain; accom-
modates bridges with spans < 1mV/V and high offset
Many diagnostic features on chip (e.g., EEPROM
signature, bridge connection checks, bridge short
detection, power loss detection)
The digital one-wire interface can be used for a simple
PC-controlled calibration procedure to program a set
of calibration coefficients into an on-chip EEPROM.
The calibrated RBicdLite™ and a specific sensor are
mated digitally: fast, precise, and without the cost
overhead associated with trimming by external
•
Independently programmable high and low clipping
levels
•
•
24-bit customer ID field for module traceability
Digital calibration and configuration via one-wire
interface – quick and precise
devices or laser. Integrated diagnostics functions
TM
make the RBicdLite
particularly well suited for
•
•
•
Internal temperature compensation reference (no
external components)
automotive applications.
Option for external temperature compensation with
addition of single diode.
•
The RBicdLiteTM Development Kit is available -
includes the Development Board, SOP8 samples,
software, and documentation.
Output options: rail-to-rail ratiometric analog voltage
(12-bit resolution), absolute analog voltage, digital one-
wire-interface
•
•
Support for industrial mass calibration is
available
•
•
•
Supply voltage 2.7 to 5.5V; with external JFET, 5.5 to
30V
Quick circuit customization possible for large
production volumes
Fast power-up to data out response; output available
5ms after power up
Current consumption depends on programmed sample
rate; 1mA down to 250μA (typical)
Application Circuit
•
•
•
•
•
Operation temperature: –50°C to +150°C
Fast response time: 1ms (typical)
Vsupply +5.5 V to 30V
S
D
V+
High voltage protection up to 30V with external JFET
No external trimming components required
JFET
Vgate
VDD
High accuracy (±0.1% FSO @ -25 to 85°C; ±0.25%
FSO @ -50 to 150°C)
RBicdLite
Brief Description
OUT/OWI
0.1µF
The RBicdLiteTM is a CMOS integrated circuit for highly
accurate amplification and sensor-specific correction
of bridge sensor signals. Digital compensation of
sensor offset, sensitivity, temperature drift and non-
linearity is accomplished via an internal digital signal
processor running a correction algorithm with cali-
bration coefficients stored in a non-volatile EEPROM.
SigTM
VBP
VBN
VSS
GND
Typical RBicdLiteTM Application Circuit
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 1 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written
consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
1
CIRCUIT DESCRIPTION ........................................................................................................................................4
1.1
1.2
1.2.1
SIGNAL FLOW AND BLOCK DIAGRAM ...................................................................................................................4
ANALOG FRONT END.............................................................................................................................................5
Bandgap/PTAT and PTAT Amplifier ............................................................................................................5
Bridge Supply................................................................................................................................................5
Pre-Amp Block..............................................................................................................................................5
Analog-to-Digital Converter (ADC).............................................................................................................5
DIGITAL SIGNAL PROCESSOR ................................................................................................................................6
EEPROM ......................................................................................................................................................7
One-Wire Interface – ZACwireTM .................................................................................................................7
OUTPUT STAGE......................................................................................................................................................7
Digital-to-Analog Converter (Output DAC) with Programmable Clipping Limits ......................................7
Output Buffer ................................................................................................................................................8
Voltage Reference Block...............................................................................................................................8
CLOCK GENERATOR / POWER ON RESET (CLKPOR)............................................................................................9
Trimming the Oscillator................................................................................................................................9
DIAGNOSTIC FEATURES.......................................................................................................................................10
EEPROM Integrity......................................................................................................................................10
Sensor Connection Check ...........................................................................................................................10
Sensor Short Check.....................................................................................................................................10
Power Loss Detection.................................................................................................................................10
ExtTemp Connection Checks ......................................................................................................................10
Output Short Circuit Protection..................................................................................................................11
1.2.2
1.2.3
1.2.4
1.3
1.3.1
1.3.2
1.4
1.4.1
1.4.2
1.4.3
1.5
1.5.1
1.6
1.6.1
1.6.2
1.6.3
1.6.4
1.6.5
1.6.6
2
FUNCTIONAL DESCRIPTION.............................................................................................................................11
2.1
2.2
2.2.1
GENERAL WORKING MODE.................................................................................................................................11
ZACWIRETM COMMUNICATION INTERFACE.........................................................................................................13
Properties and Parameters.........................................................................................................................13
Bit Encoding ...............................................................................................................................................13
Write Operation from Master to RBicdLiteTM................................................................................................14
RBicdLiteTM READ Operations......................................................................................................................14
High Level Protocol....................................................................................................................................17
COMMAND/DATA PAIR ENCODING......................................................................................................................18
CALIBRATION SEQUENCE ....................................................................................................................................20
EEPROM BITS....................................................................................................................................................22
CALIBRATION MATH ...........................................................................................................................................26
Correction Coefficients...............................................................................................................................26
Interpretation of Binary Numbers for Correction Coefficients...................................................................27
2.2.2
2.2.3
2.2.4
2.2.5
2.3
2.4
2.5
2.6
2.6.1
2.6.2
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 2 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
2.7
READING EEPROM CONTENTS ..........................................................................................................................31
3
APPLICATION CIRCUIT EXAMPLES...............................................................................................................32
3.1
THREE-WIRE RAIL-TO-RAIL RATIOMETRIC OUTPUT...........................................................................................32
ABSOLUTE ANALOG VOLTAGE OUTPUT..............................................................................................................33
THREE-WIRE RATIOMETRIC OUTPUT WITH OVER-VOLTAGE PROTECTION .........................................................34
DIGITAL OUTPUT.................................................................................................................................................34
OUTPUT RESISTOR/CAPACITOR LIMITS ...............................................................................................................35
3.2
3.3
3.4
3.5
4
5
6
ESD/LATCH-UP-PROTECTION ..........................................................................................................................35
PIN CONFIGURATION AND PACKAGE ...........................................................................................................36
IC CHARACTERISTICS........................................................................................................................................37
6.1
ABSOLUTE MAXIMUM RATINGS..........................................................................................................................37
RECOMMENDED OPERATING CONDITIONS...........................................................................................................37
ELECTRICAL PARAMETERS ..................................................................................................................................38
ANALOG INPUT VERSUS OUTPUT RESOLUTION....................................................................................................41
TEMPERATURE COMPENSATION AND TEMPERATURE OUTPUT ............................................................................42
HIGH VOLTAGE OPERATION................................................................................................................................42
6.2
6.3
6.4
6.5
6.6
7
DIE DIMENSIONS AND PAD COORDINATES.................................................................................................43
7.1
RBICDLITE™ DIE DIMENSIONS ..............................................................................................................................43
RBICDLITE™ PAD COORDINATES ..........................................................................................................................43
BONDING REQUIREMENTS ...................................................................................................................................44
7.2
7.3
8
TEST..........................................................................................................................................................................45
RELIABILITY..........................................................................................................................................................45
CUSTOMIZATION .............................................................................................................................................45
RELATED DOCUMENTS..................................................................................................................................46
9
10
11
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 3 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
1
Circuit Description
1.1 Signal Flow and Block Diagram
The RBicdLiteTM series of resistive bridge sensor interface ICs were specifically designed as cost-effective
solutions for sensing in building automation, automotive, industrial, office automation and white goods
applications.
The RBicdLiteTM employs ZMD’s high precision bandgap with proportional-to-absolute-temperature (PTAT)
output; low-power 14-bit analog-to-digital converter (ADC, A2D, A-to-D); and an on-chip DSP core with
EEPROM to precisely calibrate the bridge output signal.
Three selectable outputs, two analog and one digital, offer the ultimate in versatility across many applications.
The RBicdLite rail-to-rail ratiometric analog Vout signal (0V to ~5 V Vout @ VDD=5V) suits most building
automation and automotive requirements (12-bit resolution).
TM
Typical office automation and white goods applications require the 0 to ~1V Vout signal, which in the RBicdLite
is referenced to the internal bandgap.
Direct interfacing to μP controllers is facilitated via ZMD’s single-wire serial ZACwireTM digital interface.
RBicdLiteTM is capable of running in high-voltage (5.5-30V) systems when combined with an external JFET.
JFET
VSUPPLY = 5.5V to 30V
(Optional if supply is 2.7 to 5.5V)
S
D
VDD
(2.7-5.5V)
0.1µF
Vgate
Temperature
Reference
12-Bit
DAC
VDD
Regulator
Sensor
Diagnostics
RBicdLite
PTAT
A
D
-
SIGTM
VBP
+
0V to1 V,
VBN
ExtTemp
INMUX
14-Bit ADC
PREAMP
Rail-To-Rail
Ratiometric,
OUTBUF1
OWI/ZACwire™
Optional
Bsink
ZACwireTM
Interface
Power Save
EEPROM
W/ Charge
Pump
Digital
Core
Power Lost
Diagnostic
Optional
Ext. Diode
for Temp.
POR/Oscillator
VSS
Figure 1.1 – RBicdLiteTM Block Diagram
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 4 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
1.2 Analog Front End
1.2.1 Bandgap/PTAT and PTAT Amplifier
The Bandgap/PTAT provides the PTAT signal to the ADC, which allows accurate temperature conversion. In
addition, the ultra-low ppm Bandgap provides a stable voltage reference over temperature for the operation of
the rest of the IC. If the bridge is not near the RBicdLiteTM, an external diode can be used for temperature
measurement/compensation.
The temperature signal (internal PTAT or external diode) is amplified through a path in the Pre-Amp and fed
to the ADC for conversion. The most significant 12-bits of this converted result are used for temperature
measurement and temperature correction of bridge readings. When temperature is output in Digital Mode,
only the most significant 8 bits are given.
When external temperature is selected, add a diode from the ExtTemp pin to ground. The diode is biased with
approximately 50µA during temperature measurement cycles. The voltage level on ExtTemp is amplified
through the Pre-Amp and converted by the ADC. Ensure that the ExtTemp signal is in the range of 150mV to
800mV to prevent saturation of the ADC. If the selected diode has a sensitivity in the range of 1.9mV/oC to
3.25mV/oC, a corrected temperature output (in Digital Mode) can be achieved for a 200oC temperature span
(-50oC to 150oC).
1.2.2 Bridge Supply
TM
The voltage-driven bridge is usually connected to VDD and ground. As a power savings feature, the RBicdLite
also includes a switched transistor to interrupt the bridge current via pin 1 (Bsink). The transistor switching is
synchronized to the A-to-D conversion and released after finishing the conversion. To utilize this feature, the
low supply of the bridge should be connected to Bsink instead of ground.
Depending on the programmable update rate, the average current consumption (including bridge current) can
be reduced to approximately 20%, 5% or 1%.
1.2.3 Pre-Amp Block
The differential signal from the bridge is amplified through a chopper-stabilized instrumentation amplifier with
very high input impedance designed for low noise and low drift. This pre-amp provides gain for the differential
signal and re-centers its DC to VDD/2. The output of the Pre-Amp block is fed into the ADC. The calibration
sequence performed by the digital core includes an auto-zero sequence to null any drift in the Pre-Amp state
over temperature.
The Pre-Amp can be set to a gain of 6, 24, 48 or 96 through EEPROM.
The inputs to the Pre-Amp from (VBN/VBP pins) can be reversed via an EEPROM configuration bit.
1.2.4 Analog-to-Digital Converter (ADC)
A 14-bit/1ms 2nd order charge-balancing ADC is used to convert signals coming from the pre-amplifier. The
converter, designed in full differential switched capacitor technique, is used for converting the various signals
in the digital domain. This principle offers the following advantages:
•
•
•
High noise immunity because of the differential signal path and integrating behavior
Independence from clock frequency drift and clock jitter
Fast conversion time owing to second order mode
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 5 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
Four selectable values for the zero point of the input voltage allow conversion to adapt to the sensor’s offset
parameter. With the Reverse Input Polarity Mode, this results in four possible zero point adjustments.
The conversion rate varies with the programmed update rate. The fastest conversation rate is 1k samples/s
and the response time is then 1ms. Based on a best fit, the Integral Nonlinearity (INL) is less than 4 LSB14Bit.
1.3 Digital Signal Processor
A digital signal processor (DSP) is used for processing the converted bridge data as well as performing
temperature correction and computing the temperature value for output on the digital channel.
The digital core reads correction coefficients from EEPROM and can correct for the following:
1. Bridge Offset
2. Bridge Gain
3. Variation of Bridge Offset over Temperature (Tco)
4. Variation of Bridge Gain over Temperature (Tcg)
5. A single second order effect (SOT) (Second Order Term)
The EEPROM contains a single SOT that can be applied to correct one and only one of the following:
•
•
•
2nd order behavior of bridge measurement
2
2
nd order behavior of Tco
nd order behavior of Tcg
If the SOT applies to correcting the bridge reading, then the correction formula for the bridge reading is
represented as a two step process as follows:
ZB
BR
= Gain_B [1 + ΔTꢀTcg]ꢀ[BR_Raw + Offset_B + ΔTꢀTco]
= ZBꢀ(1.25+SOTꢀZB)
Where:
BR
ZB
=
=
Corrected Bridge reading that is output as digital or analog on SIGTM pin
Intermediate result in the calculations
Raw Bridge reading from ADC
BR_Raw =
T_Raw
Gain_B
=
=
Raw Temp reading converted from PTAT signal or external diode
Bridge Gain term
Offset_B =
Bridge Offset term
Tcg
Tco
ΔT
TSETL
SOT
=
=
=
=
=
Temperature Coefficient Gain
Temperature Coefficient Offset
(T_Raw - TSETL
)
T_Raw reading at which low calibration was performed (typically 25°C)
Second Order Term
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 6 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
If the SOT applies to correcting 2nd order behavior of Tco then the formula for bridge correction is as follows:
BR = Gain_B[1 + ΔTꢀTcg]ꢀ[BR_Raw + Offset_B + ΔT(SOTꢀΔT + Tco)]
If the SOT applies to correcting 2nd order behavior of Tcg then the formula for bridge correction is as follows:
BR = Gain_B[1 + ΔT(SOTꢀΔT + Tcg)]ꢀ[BR_Raw + Offset_B + ΔTꢀTco]
The bandgap reference gives a very linear PTAT signal, so temperature correction can always be
accomplished simply with a linear gain and offset term.
Corrected Temp Reading:
T
= Gain_Tꢀ[T_Raw + Offset_T]
Where:
T_Raw
=
Raw Temperature reading converted from PTAT signal or external diode
Offset_T = Offset Coefficient for Temperature
Gain_T Gain Coefficient for Temperature
=
1.3.1 EEPROM
The EEPROM contains the calibration coefficients for gain and offset, etc., and the configuration bits, such as
output mode, update rate, etc. The RBicdLiteTM also offers 3 user programmable storage bytes for module
traceability. When programming the EEPROM, an internal charge pump voltage is used; therefore a high
voltage supply is not needed.
The charge pump is internally regulated to 12.5 V, and the programming time is 6ms.
See section 1.6.1 regarding EEPROM signatures for verifying EEPROM integrity.
1.3.2 One-Wire Interface – ZACwireTM
The IC communicates via a one-wire serial interface. There are different commands available for the
following:
•
•
•
•
Reading the conversion result of the ADC (Get_BR_Raw, Get_T_Raw)
Calibration commands
Reading from the EEPROM (dump of entire contents)
Writing to the EEPROM (trim setting, configuration, and coefficients)
1.4 Output Stage
1.4.1 Digital-to-Analog Converter (Output DAC) with Programmable Clipping Limits
A 12-bit DAC based on sub-ranging resistor strings is used for the digital-to-analog output conversion in the
analog ratiometric and absolute analog voltage modes. Options during calibration configure the system to
operate in either of these modes. The design allows for excellent testability as well as low power
consumption. The DAC allows programming a lower and upper clipping limit for the output signal (analog and
digital). The internal 14-bit calculated bridge value is compared against the 14-bit value formed by
{11,Up_Clip_Lim[6:0],11111} for the upper limit and {00,Low_Clip_Lim[6:0],00000} for the lower limit. If the
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 7 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
calculated bridge value is higher than the upper limit or less than the lower limit, the analog output value is
clipped to this value; otherwise it is output as is.
Example for the upper clipping level: If the Up_Clip_Lim[6:0] = 0000000, then the 14-bit value used for
clipping threshold is 11000000011111. This is 75.19% of full scale. Since there are 7 bits of upper clipping
limit, there are 127 possible values between 75.19% and 100%. Therefore the resolution of the clipping limits
0.195%.
Example for the lower clipping level: If the Low_Clip_Lim[6:0] = 1111111, then the 14-bit value used for
clipping threshold is 00111111100000. This is 24.8% of full scale. Since there are 7 bits of lower clipping limit,
there are 127 possible values between 0 and 24.8%. Therefore the resolution of the lower clipping limit is
0.195%.
1.4.2 Output Buffer
A rail-to-rail op amp configured as a unity gain buffer can drive resistive loads (whether pull-up or pull-down)
as low as 5kΩ and capacitances up to 15nF (for pure analog output). In addition, to limit the error due to
amplifier offset voltage, an error compensation circuit is included which tracks and reduces offset voltage to <
1mV.
1.4.3 Voltage Reference Block
This block uses the absolute reference voltage provided by the bandgap to produce two regulated on-chip
voltage references. A 1V reference is used for the output DAC high reference when the part is configured in
0-1V Analog Output Mode. For this reason, the 1V reference must be very accurate and includes trim so that
its value can be trimmed within +/- 2mV of 1.00V. The 1V reference is also used as the on-chip reference for
the JFET regulator block. The regulation set point of the JFET regulator can be fine tuned using the 1V trim.
1V Reference Trim (1V vs. Trim for Nominal Process Run):
1Vref_trim3 1Vref_trim2 1Vreft_trim1 1Vref_trim0 1Vref deltaV
5Vref deltaV
-0.0920
-0.0805
-0.0690
-0.0575
-0.0460
-0.0345
-0.0230
-0.0115
Nominal
+0.0115
+0.0230
+0.0345
+0.0460
+0.0575
1
1
1
1
1
1
1
1
0
0
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
-0.0184
-0.0161
-0.0138
-0.0115
-0.0092
-0.0069
-0.0046
-0.0023
Nominal
+0.0023
+0.0046
+0.0069
+0.0092
+0.0115
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 8 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
1Vref_trim3 1Vref_trim2 1Vreft_trim1 1Vref_trim0 1Vref deltaV
5Vref deltaV
0
0
0
0
0
0
1
0
+0.0138
+0.0161
+0.0690
+0.0805
Sample: Programming “0000” → the trimmed voltage = nominal value + 0.0161V
1.5 Clock Generator / Power On Reset (CLKPOR)
If the power supply exceeds 2.5V (maximum), the reset signal de-asserts and the clock generator starts
working at a frequency of approximately 512kHz (±20%). The exact value only influences the conversion
cycle time and communication to the outside world but not the accuracy of signal processing. In addition, to
minimize the oscillator error as the VDD voltage changes, an on-chip regulator is used to supply the oscillator
block.
1.5.1 Trimming the Oscillator
Trimming is performed at wafer level, and it is strongly recommended that this not be changed during
calibration because ZACwireTM communication is not guaranteed at different oscillator frequencies.
Trimming Bits
Delta Frequency
(KHz)
100
101
+385
+235
110
+140
+65
111
000
001
010
011
Nominal
-40
-76
-110
Sample: Programming ”011” → the trimmed frequency = nominal value – 110KHz
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 9 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
1.6 Diagnostic Features
The RBicdLiteTM offers a full suite of diagnostic features to ensure robust system operation in the most
“mission-critical” applications. If the part is programmed in Analog Output Mode, then diagnostic states are
indicated by an output below 2.5% of VDD or above 97.5% of VDD. If the part is programmed in Digital
Output Mode, then diagnostic states will be indicated by a transmission with a generated parity error.
1.6.1 EEPROM Integrity
The contents of the EEPROM are protected by an 8-bit LFSR signature (linear feedback shift register). This
signature is regenerated and stored in EEPROM every time EEPROM contents are changed. This signature
is generated and checked for a match after Power-On-Reset prior to entering Normal Operation Mode. If the
generated signature fails to match, the part will output a diagnostic state on the output.
In addition to an extensive temporal and code interlock mechanism used to prevent false writes to the
EEPROM, the RBicdLiteTM offers an EEPROM lock mechanism for high-security applications. When EEPROM
bits 105:103 are programmed with “011” or “110,” this 3-bit field will permanently disable the VPP charge
pump and will not allow further writes to the EEPROM.
1.6.2 Sensor Connection Check
Four dedicated comparators permanently check the range of the bridge inputs (BP/BN) to ensure they are
within the envelope of 0.8V to 0.85ꢀVDD during all conversions. The two sensor inputs have a switched ohmic
path to ground and if left floating, would be discharged. If any of the wires connecting the bridge break, this
mechanism will detect it and put the ASIC in a diagnostic state. This same diagnostic feature can also detect
a short between BP/BN and the ExtTemp signal if an external diode is being used for temperature
measurement.
1.6.3 Sensor Short Check
If a short occurs between BP/BN (bridge inputs), it would normally produce an in-range output signal and
therefore would not be detected as a fault. This diagnostic mode, if enabled, will deliberately look for such a
short. After the measurement cycle of the bridge, it will deliberately pull the BP bridge input to ground for
4μsec. At the end of this 4μsec window, it will check to see if the BN input “followed” it down below the 0.8V
comparator checkpoint. If so, a short must exist between BP/BN, and the part will output a diagnostic state.
The bridge will have a minimum of 480μsec recovery time prior to the next measurement.
1.6.4 Power Loss Detection
If the power or GND connection to the module containing the sensor bridge and ASIC is lost, the ASIC will
output a diagnostic state if a pull-up or pull-down terminating resistor greater than or equal to 5kΩ is
connected in the final application. This diagnostic mode only works when the part is configured in Analog
Output Mode.
1.6.5 ExtTemp Connection Checks
When external temperature is selected and connection checking is enabled, the part performs range checking
on the converted temperature value. If the internal ADC reading of the temperature is less than 1/32 of full
scale or greater than 63/64 of full scale then a diagnostic state is asserted. If the ExtTemp pin is shorted to
ground, the ADC reads less than 1/32. Because 100µA is sourced onto the ExtTemp pin during conversions,
it naturally pulls up during these times. If the ExtTemp pin is open, it produces an ADC reading greater than
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 10 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
63/64 of full scale. Both these bad connection conditions would be detected and result in a diagnostic output.
If internal temperature is selected or sensor connection check is not enabled, then this diagnostic check is not
enabled.
1.6.6 Output Short Circuit Protection
The output of the RBicdLiteTM can be permanently shorted to VDD or VSS without damaging the device. The
output driver contains a current-limiting block that detects a hard short and limits the current to a safe level.
Detected Fault
Analog
ZACwireTM Diagnostic
Delay of Detection
Diagnostic Level
EEPROM signature
Loss of bridge positive
Loss of bridge negative
Open bridge connection
Bridge input short
Lower
Upper
Upper
Upper
Upper
Lower
Lower
Generates parity error
Generates parity error
Generates parity error
Generates parity error
Generates parity error
Generates parity error
Generates parity error
10ms after Power On
2ms
2ms
2ms
2ms
ExtTemp pin open
300ms
300ms
ExtTemp pin shorted to
PWR/GND
ExtTemp pin shorted to BP/BN Upper
Generates parity error
Transmissions stop
Transmissions stop
3ms
Loss of VDD
Loss of VSS
Lower
Upper
Dependent on RL and CL
Dependent on RL and CL
2
Functional Description
2.1 General Working Mode
The command/data transfer takes place via the one-wire SIG™ pin using the ZACwireTM serial communication
protocol.
After power-on, the IC waits for 1.5ms (= Command window) for the Start_CM command.
Without this command, the Normal Operation Mode (NOM) starts. In this mode, raw bridge values are
converted, and the corrected values are presented on the output in analog or digital format (depending on the
configuration stored in EEPROM).
Command Mode (CM) can only be entered during the 1.5ms command window after Power ON. If the IC
receives the Start_CM command during the command window, it remains in the Command Mode. The CM
allows changing to one of the other modes via command. After command Start_RW, the IC is in the Raw
Mode. Without correction, the raw values are transmitted to the digital output in a predefined order. The RM
can only be stopped by Power OFF. Raw Mode is used by the calibration software for collection of raw bridge
and temperature data so the correction coefficients can be calculated.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 11 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
If diagnostic features are enabled and a diagnostic fault is detected, diagnostic states are indicated as follows
depending on the programmed mode:
•
In Analog Output Mode:
Diagnostic states are indicated by an output below 2.5% of VDD or above 97.5% of VDD.
•
In Digital Output Mode:
Diagnostic states will be indicated by a transmission with a generated parity error.
For more details see chapter 1.6.
Power
ON
Command
Start_CM
Window (1.5ms)
Send Start_CM
No Command
Start_NOM
Start_RM
Raw Mode
Command Mode
Normal Operation Mode
No commands possible
Measurement cycle
Measurement cycle
stopped
Measurement cycle
SIG™ pin provides raw
bridge and temperature
values in the format
Conditioning calculation
Full command set
Corrected bridge and
temperature values
Command routine will
be processed after
each command
Bridge_high (1st Byte)
Bridge_low (2nd Byte)
Depending on the con-
figuration, the SIG™ pin is
Temp
(3rd Byte)
• 0V-1V
• Rail-to-rail ratiometric
• Digital output
Diagnostics functions
Error
Detection
Power OFF
Diagnostic State
(See section 1.6)
Figure 2.1 – General Working Mode
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 12 of 46
© ZMD AG, 2006
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written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
2.2 ZACwireTM Communication Interface
2.2.1 Properties and Parameters
Parameter
Symbol Min Typ Max Unit Comments
1
2
Pull-up resistor
(on-chip)
RZAC,pu
30
On-chip pull-up resistor switched on
during Digital Output Mode and during
CM Mode (first 1.5ms after power up)
kΩ
ZACwireTM rise time
tZAC,rise
5
Any user RC network included in the
SIGTM path must meet this rise time.
μs
3
4
ZACwireTM line resistance
RZAC,load
CZAC,load
3.9
15
Also see section 6.3.
kΩ
ZACwireTM load
capacitance
0
1
nF Also see section 6.3.
5
6
Voltage level - low
Voltage level - high
VZAC,low
VZAC,high
0
1
0.2
VDD Rail-to-rail CMOS driver
VDD Rail-to-rail CMOS driver
0.8
2.2.2 Bit Encoding
Duty cycle encoded Manchester:
Bit Window
Start bit => 50% duty cycle used
to set up strobe time
Start Bit
Logic 1
Logic 0
Logic 1 => 75% duty cycle
Logic 0 => 25% duty cycle
Stop Bit
Stop ½ Bit
(High)
For the time of a half a bit width, the signal level is high.
There is a half stop bit time between bytes in a packet.
Figure 2.2 – Duty Cycle Manchester
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 13 of 46
© ZMD AG, 2006
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written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
TM
2.2.3 Write Operation from Master to RBicdLite
The calibration master sends a 19-bit packet frame to the IC.
S
P
2
Start Bit
19-Bit Frame (WRITE)
Parity Bit Command Byte
or Parity Bit Data Byte
S 7 6 5 4 3 2 1 0 P 7 6 5 4 3 2 1 0 P
Command Bit (Example: Bit 2)
Data Bit (Example: Bit 2)
2
Command Byte
Data Byte
Figure 2.3 – 19-Bit Write Frame
The incoming serial signal will be sampled at a 512kHz clock rate. This protocol is very tolerant to clock skew
and can easily tolerate baud rates in the 6kHz to 48kHz range.
2.2.4 RBicdLiteTM READ Operations
The incoming frame will be checked for proper parity on both command and data bytes, as well as for any
edge timeouts prior to a full frame being received.
Once a command/data pair is received, the RBicdLiteTM will perform that command. Once the command has
been successfully executed by the IC, it will acknowledge success by transmission of an A5H byte back to the
master. If the master does not receive an A5H transmission within 130ms of issuing the command, it must
assume the command was either improperly received or could not be executed.
S
P
0
Start Bit
1 DATA Byte Packet
10-Bit Byte A5H
Parity Bit Data Byte
Data Bit (Low)
Data Bit (High)
S 1 0 1 0 0 1 0 1 P
1
Data Byte
Figure 2.4 – Read Acknowledge
The RBicdLiteTM transmits 10-bit bytes (1 start bit, 8 data, 1 parity). During calibration and configuration,
transmissions are normally either A5H or data. A5H indicates successful completion of a command. There are
two different digital output modes configurable (digital output with temperature and digital output with only
bridge data). During Normal Operation Mode, if the part is configured for digital output of the bridge reading, it
first transmits the high byte of bridge data followed by the low byte. The bridge data is 14-bits in resolution, so
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 14 of 46
© ZMD AG, 2006
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written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
the upper two bits of the high byte are always zero padded. There is a half stop bit time between bytes in a
packet. This means for the time of a half a bit width, the signal level is high.
2 DATA Byte Packet
Digital Bridge Output
S
P
2
Start Bit
Parity Bit Data Byte
Data Bit (Example: Bit 2)
½ Stop Bit
½
Stop
S 0 0 5 4 3 2 1 0 P
Data Byte Bridge High
S 7 6 5 4 3 2 1 0 P
Data Byte Bridge Low
½
Stop
Figure 2.5 – Digital Output (NOM) Bridge Readings
The second option for Digital Output Mode is digital output bridge reading with temperature. It will be trans-
mitted as 3 data packets. The temperature byte represents an 8-bit temperature quantity spanning from -50°C
to +150°C.
3 DATA Byte Packet
Digital Bridge Output with Temperature
½
Stop
½
Stop
S 0 0 5 4 3 2 1 0 P
Data Byte Bridge High
S 7 6 5 4 3 2 1 0 P
S 7 6 5 4 3 2 1 0 P
Data Byte Bridge Low
Data Byte Temperature
Figure 2.6 – Digital Output (NOM) Bridge Readings with Temperature
The EEPROM transmission occurs in a packet with 20 data bytes as shown in Figure 2.7.
20 DATA Byte Packet
Read EEPROM
½
Stop
½
Stop
½
S 7 6 5 4 3 2 1 0 P
S 7 6 5 4 3
4 3 2 1 0 P
EEPROM 18
S 7 6 5 4 3 2 1 0 P
S 1 0 1 0 0 1 0 1 P
Data Byte A5H
Stop
EEPROM Byte 1
EEPROM Byte 2
EEPROM Byte 19
Figure 2.7 – Read EEPROM Contents
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 15 of 46
© ZMD AG, 2006
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written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
There is a variable idle time between packets. This idle time varies with the update rate setting in EEPROM.
Packet Transmission
(This example shows 2 data packets.)
IDLE
TIME
½
Stop
IDLE
TIME
½
Stop
IDLE
S 0 0 5 4 3
TIME
6 5 4 3 2 1 0 P
S 0 0 5 4 3 2 1 0 P
S 7 6 5 4 3 2 1 0 P
S 0 0 5 4 3 2 1 0 P
S 7 6 5 4 3 2 1 0 P
7
Figure 2.8 – Transmission of a Number of Data Packets
The table below shows the idle time between packets versus update rate. This idle time can vary by nominal
+/-15% between parts and over a temperature range of –50°C to 150°C.
Update Rate Setting
Idle Time between Packets
00
01
10
11
1ms
4.85ms
22.5ms
118ms
Transmissions from the IC occur at one of two speeds depending on the update rate programmed in
EEPROM. If the user chooses one of the two fastest update rates (1ms or 5ms) then the baud rate of digital
transmission will be 32kHz. If however, the user chooses one of the two slower update rates (25ms or
125ms), then the baud rate of digital transmission will be 8kHz.
The total transmission time for both digital output configurations is shown in Table 2.1.
Table 2.1 – Total Transmission Time for Different Update Rate Settings and Output Configuration
Baud
Rate
Transmission Time –
Bridge Only Readings
Transmission Time –
Bridge & Temperature Readings
Update Rate
Idle Time
1ms (1kHz)
5ms (200Hz)
25ms (40Hz)
125ms (8Hz)
32kHz
32kHz
8kHz
1.00ms
4.85ms
20.5 bits
31.30µs
31.30µs
1.64ms
31.0 bits
31.0 bits
31.0 bits
31.0 bits
31.30µs
31.30µs
1.97ms
5.82ms
20.5 bits
20.5 bits
20.5 bits
5.49ms
25.06ms
120.56ms
22.50ms
118.00ms
125.00µs
125.00µs
125.00µs
125.00µs
26.38ms
121.88ms
8kHz
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 16 of 46
© ZMD AG, 2006
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written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
Figure 2.9 shows the data timing of the DAC output for the update rate setting 00.
Settling Time
64µs
ADC Conversion
768µs
Calculation
160µs
Settling Time
64µs
ADC Conversion
768µs
Calculation
160µs
DAC output
occurs here
DAC output
next update
Figure 2.9 – DAC Output Timing for Highest Update Rate
For lower update rates, the DAC output is followed by a power-down as shown in Figure 2.10.
Calculation
160µs
Power-Down
Determined by
Update Rate
Power-On
Settling
128µs
Settling time
64µs
ADC
Conversion
768µs
Calculation
160µs
DAC output
occurs here!
DAC output
next update
Figure 2.10 – DAC Output Timing for Lower Update Rates
One can easily program any standard μcontroller to communicate with the RBicdLiteTM. ZMDA can provide
sample code for a MicroChip PIC μController.
2.2.5 High Level Protocol
The RBicdLiteTM will listen for a command/data pair to be transmitted for the 1.5 ms after the de-assertion of its
internal Power On Reset (POR). If a transmission is not received within this time frame, then it will transition
to Normal Operation Mode (NOM). In the NOM, it will output bridge data in 0-1V analog, rail-to-rail ratiometric
analog, or digital depending on how the part is currently configured.
If the RBicdLiteTM receives a Start_CM command within the first 1.5 ms after the de-assertion of POR, then it
will go into Command Mode (CM). In this mode, calibration/configuration commands will be executed. The
RBicdLiteTM will acknowledge successful execution of commands by transmission of A5H. The calibrating
/configuring master will know a command was not successfully executed if no response is received after
130ms of issuing the command. Once in command interpreting/executing mode, the RBicdLiteTM will stay in this
mode until power is removed or a Start NOM (Start Normal Operation Mode) command is received. The
Start_CM command is used as an interlock mechanism to prevent a spurious entry into Command Mode on
power up. The first command received within the 1.5ms window of POR must be a Start_CM command to
enter into command interpreting mode. Any other commands will be ignored.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 17 of 46
© ZMD AG, 2006
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written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
2.3 Command/Data Pair Encoding
The 2-byte command sent to the RBicdLiteTM consists of 1 byte of command information and 1 byte of data
information. Regardless of whether the command requires data or not, 2 bytes MUST be sent. The following
table lists all the command/data pairings. (X=don’t care.)
Command Data
Byte
Description
00H
20H
XXH
YXH
Read EEPROM command via SIGTM pin.
Enter Test Mode (subset of Command Mode for testing purposes only). The SIGTM pin
will assume the value of different internal test points, depending on the most
significant nibble of data sent.
Y = 0H => Internal oscillator
Y = 1H => 2.5V reference
Y = 2H => PTAT
Y = 3H => Pre-Amp Output+
Y = 4H => Scan Mode (SDO* routed to SIG TM pin; part goes into Clock Override Mode
and Scan Mode)
Y = 5H => DAC Ramp Test Mode. Gain_B[13:3] contains the starting point, and the
increment is (Offset_B/8). The increment will be added every 125μsec.
Y = 6H => Negative charge pump oscillator out.
Y = 7H => Part goes into Clock Override Mode.
Y = 8-FH => Undefined.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 18 of 46
© ZMD AG, 2006
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written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
Command Data
Byte
Description
Trim/Configure: 3rd nibble determines what is trimmed/configured. The 4th nibble is
data to be programmed.
30H
WDH
3rd Nibble 4th Nibble Data
Description
W =>
What
0H
1H
2H
3H
4H
5H
6H
XH
XH
XH
XH
XH
XH
XH
Trim oscillator. Least significant 3 bits of data used.
Trim 1V reference. Least significant 4 bits of data used.
Offset Mode. Least significant 2 bits of data used.
Set output mode. Least significant 2 bits used.
Set update rate. Least significant 2 bits used.
Configure JFET regulation
D =>
Data
H =>
Hex
Program the Tc_cfg register. Least significant 3 bits used.
Most significant bit of data nibble should be 0.
7H
8H
9H
AH
BH
CH
XH
XH
XH
XH
XH
XH
Program EEPROM bits [99:96] {SOT_cfg,Pamp_Gain}
Clear all case: Used to clear all bits in EEPROM to 0.
0101… case: Sets whole EEPROM to alternating pattern.
1010…case: Sets opposite alternating pattern.
Set all case: Sets all EEPROM bits to 1.
EEPROM Endurance Mode.
Initial setting of Offset_B[13:3] determines the # of cycles.
Offset_T must be programmed to zero initially.
DH
XH
Program EEPROM lock field. Least significant 3 bits used.
011 => locked
EH
FH
XH
Program diagnostic config field. 3 bits of data used.
Reserved.
XH
40H
40H
00H
10H
Start NOM => Ends Command Mode; transition to Normal Operation Mode.
Start_RM = Start the Raw Mode (RM)
In this mode, if Gain_B = 800H and Gain_T = 80H, then the digital output will simply
be the raw values of the ADC for the Bridge reading, and the PTAT conversion.
50H
60H
70H
90H
YYH
YYH
Start_CM => Start the Command Mode; used to enter Command Interpret Mode.
Program SOT (2nd Order Term)
Program TSETL (Set the MSB to 0.)
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 19 of 46
© ZMD AG, 2006
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ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
Command Data
Byte
Description
80H
90H
A0H
B0H
C0H
YYH
YYH
YYH
YYH
YYH
YYH
YYH
YYH
YYH
YYH
YYH
YYH
YYH
Program Gain_B upper 7-bits (Set the MSB to 0.)
Program Gain_B lower 8-bits
Program Offset_B upper 6-bits (Set the two MSBs to 0.)
Program Offset_B lower 8-bits
Program Gain_T
D0H
E0H
F0H
08H
18H
28H
38H
48H
Program Offset_T
Program Tco
Program Tcg
Program Upper Clipping Limit (Set the MSB to 0.)
Program Lower Clipping Limit (Set the MSB to 0.)
Program Cust_ID0
Program Cust_ID1
Program Cust_ID2
*SDO: Scan Data Out
2.4 Calibration Sequence
Although the RBicdLiteTM IC can work with many different types of resistive bridges, assume a pressure bridge
for the following discussion on calibration.
Calibration essentially involves collecting raw bridge and temperature data from the IC for different known
pressures and temperatures. This raw data can then be processed by the calibration master (typically a PC)
to compute the coefficients, and the calculated coefficients can then be written to the IC.
ZMDA can provide software and hardware with samples to perform the calibration.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 20 of 46
© ZMD AG, 2006
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ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
There are three main steps to calibration:
1. Assigning a unique identification to the IC. This identification is programmed in EEPROM and can be
used as an index into the database stored on the calibration PC. This database will contain all the raw
values of bridge readings and temperature readings for that part, as well as the known pressure (for
this application) and temperature the bridge was exposed to. This unique identification can be stored
in a concatenation of the following EEPROM registers: Cust_ID0, Cust_ID1, Cust_ID2. These
registers can also form a permanent serial number.
2. Data collection. Data collection involves getting raw data from the bridge at different known pressures
and temperatures. This data is then stored on the calibration PC using the unique identification of the
IC as the index to the database.
3. Coefficient calculation and write. Once enough data points have been collected to calculate all the
desired coefficients then the coefficients can be calculated by the calibrating PC and written to the IC.
Step 1 – Assigning Unique Identification
Assigning a unique identification number is as simple as using the commands Program Cust_ID0, Program
Cust_ID1 and Program Cust_ID2. These three 8-bit registers allow for more than 16 million unique devices.
Gain_B must be programmed to 800H (unity) and Gain_T must be programmed to 80H (unity).
Step 2 – Data Collection
The number of unique (pressure, temperature) points that calibration must be performed at depends on the
customer’s needs. The minimum is a 2-point calibration, and the maximum is a 5-point calibration. To acquire
raw data from the part, set RBicdLiteTM to enter Raw Mode. This is done by issuing a Start_CM (Start
Command Mode 5090H) command/data pair to the IC followed by a Start_RM (Start Raw Mode 4010H)
command/data pair with the LSB of the upper data nibble set. Now if the Gain_B term has been set to unity
(800H) and the Gain_T term has also been set to unity (80H), then the part will be in the Raw Mode and will
output raw data on its SIGTM pin instead of corrected bridge and temperature. Capture several of these data
points with the user’s calibration system (16 each of bridge and temperature is recommended) and average
them. Store these raw bridge and temperature settings in the database along with the known pressure and
temperature. The output format during Raw Mode is Bridge_High, Bridge_Low, Temp. Each of these is an 8-
bit quantity. The upper 2-bits of Bridge_High are zero filled. The Temp data (8-bits only) would not be enough
information for accurate temperature calibration. Therefore the upper three bits of temperature information are
not given, but rather assumed known. Therefore effectively 11-bits of temperature information are provided in
this mode.
Step 3 – Coefficient Calculations
The math to perform the coefficient calculation is very complicated and will not be discussed in detail. There is
a rough overview in the “Calibration Math” section. ZMDA will provide software to perform the coefficient
calculation. ZMDA can also provide source code for the algorithms in a C code format. After the coefficients
TM
are calculated, the final step is to write them to the EEPROM of the RBicdLite
.
The number of calibration points required can be as few as two or as many as five. This depends on the
precision desired and the behavior of the resistive bridge in use.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 21 of 46
© ZMD AG, 2006
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written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
1. 2-point calibration can be used if only a gain and offset term are needed for a bridge with no
temperature compensation for either term.
2. 3-point calibration would be used to obtain 1st order compensation for either a Tco or Tcg term but not
both.
3. 3-point calibration could also be used to obtain 2nd order correction for the bridge but no temperature
compensation of the bridge output.
4. 4-point calibration would be used to obtain 1st order compensation for both Tco and Tcg.
5. 4-point calibration could also be used to obtain 1st order compensation for Tco and a 2nd order
correction for the bridge measurement.
6. 5-point calibration would be used to obtain both 1st order Tco correction and 1st order Tcg correction,
plus a 2nd order correction that could be applied to one and only one of the following: 2nd order Tco,
2nd order Tcg, or 2nd order bridge.
2.5 EEPROM Bits
Programmed through the serial interface:
EEPROM
Range
Description
Osc_Trim
Note
2:0
See the table in the “Trimming the Oscillator”
section for complete data.
100 => Fastest
101 => 3 clicks faster than nominal
110 => 2 clicks faster than nominal
111 => 1 click faster than nominal
000 => Nominal
001 => 1 click slower than nominal
010 => 2 clicks slower than nominal
011 => Slowest
6:3
1V_Trim/JFET_Trim See the table under “Voltage Reference Block,”
section 1.4.3.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 22 of 46
© ZMD AG, 2006
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ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
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EEPROM
Range
Description
A2D_Offset
Note
10:7
The upper two bits are flip polarity and invert
bridge input (negative gain) respectively. If both
are used in conjunction, negative offset modes
can be achieved.
00 => normal polarity, positive gain
01 => normal polarity, negative gain
10 => flip polarity, positive gain
11 => flip polarity, negative gain
The lower two bits form the ADC offset
selection.
Offset selection:
11 => [-1/2,1/2] mode bridge inputs
10 => [-1/4,3/4] mode bridge inputs
01 => [-1/8,7/8] mode bridge inputs
00 => [-1/16,15/16] mode bridge inputs
12:11
Output_Select
00 => Digital (3 bytes with parity)
Bridge High {00,[5:0]}
Bridge Low [7:0]
Temp [7:0]
01 => 0-1V Analog
10 => Rail-to-Rail Ratiometric
11 => Digital (2 bytes with parity) (No Temp)
Bridge High {00,[5:0]}
Bridge Low [7:0]
14:13
16:15
Update_Rate
JFET_cfg
00 => 1 msec (1kHz)
01 => 5 msec (200Hz)
10 => 25 msec (40Hz)
11 => 125 msec (8 Hz)
00 => No JFET regulation (lower power)
01 => No JFET regulation (lower power)
10 => JFET regulation centered around 5.0V
11 => JFET regulation centered around 5.5V
(i.e. over-voltage protection).
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 23 of 46
© ZMD AG, 2006
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written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
EEPROM
Range
Description
Gain_B
Note
31:17
Bridge Gain (also see bits 10:7 ):
Gain_B[14] => multiply x 8
Gain_B[13:0] => 14-bit unsigned number repre-
senting a number in the range [0,8)
45:32
53:46
Offset_B
Gain_T
Unsigned 14-bit offset for bridge correction
Temperature gain coefficient used to correct
PTAT or ExtTemp reading
61:54
68:62
Offset_T
TSETL
Temperature offset coefficient used to correct
PTAT or ExtTemp reading
Stores Raw PTAT or ExtTemp reading at
temperature in which low calibration points were
taken
76:69
84:77
87:85
Tcg
Coefficient for temperature correction of bridge
gain term:
Tcg = 8-bit magnitude of Tcg term. Sign is
determined by Tc_cfg (bits 87:85).
Tco
Coefficient for temperature correction of bridge
offset term.
Tco = 8-bit magnitude of Tco term. Sign and
scaling are determined by Tc_cfg (bits 87:85)
Tc_cfg
This 3-bit term determines options for
temperature compensation of the bridge.
Tc_cfg[2] => If set, Tcg is negative
Tc_cfg[1] => Scale magnitude of Tco term by 8,
and if SOT applies to Tco, scale
SOT by 8
Tc_cfg[0] => If set, Tco is negative
95:88
SOT
2nd Order Term. This term is a 7-bit magnitude
with sign.
SOT[7] = 1 Î negative
SOT[7] = 0 Î positive
SOT[6:0] = magnitude [0-127]
This term can apply to a 2nd order Tcg, Tco or
bridge correction. (See Tc_cfg above.)
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 24 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
EEPROM
Range
Description
{SOT_cfg,
Note
Bits [99:98] = SOT_cfg
99:96
Pamp_Gain}
00 = SOT applies to Bridge
01 = SOT applies to Tcg
10 = SOT applies to Tco
11 = Prohibited
Bits [97:96] = Pre-Amp Gain
00 => 6
01 => 24 (default setting)
10 => 48
11 => 96
102:100
105:103
Diag_cfg
This 3-bit term applies to diagnostic features
Diag_cfg[2] Æ enable output short circuit
protection.
Diag _cfg[1] Æ enable sensor short checking.
Diag_cfg[0] Æ enables sensor connection
checking.
Lock_ExtTemp
EEPROM lock
011 or 110 => locked
All other
=> unlocked
When EEPROM is locked, the internal charge
pump is disabled and the EEPROM can never
be programmed again.
Bit 105 (the MSB of this field) is also used for
selecting external temperature measurement.
0XX => Internal PTAT used for temp
1XX => External diode used for temp
112:106
119:113
Up_Clip_Lim
Low_Clip_Lim
7-bit value used to select an upper clipping limit
for the output. It affects both analog and digital
output. The 14-bit upper clipping limit value is
comprised of {11,Up_Clip_Lim[6:0],11111}. 127
different clipping levels are selectable between
75.19% and 100% of VDD.
7-bit value used to select a lower clipping limit
for the output. It affects both analog and digital
output. The 14-bit lower clipping limit value is
comprised of {00,Low_Clip_Lim[6:0],00000}.
127 different clipping levels are selectable
between 0% and 24.8% of VDD.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 25 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
EEPROM
Range
Description
Cust_ID0
Note
127:120
Customer ID byte 0
Customer ID byte 1
Customer ID byte 2
135:128
143:136
151:144
Cust_ID1
Cust_ID2
Signature
8-bit EEPROM signature. Generated through a
LFSR1. This signature is checked on power-on
to ensure integrity of EEPROM contents.
2.6 Calibration Math
2.6.1 Correction Coefficients
(All terms calculated external to the DUT and then programmed to EEPROM through serial interface.)
Gain_B =
Offset_B =
Gain_T =
Offset_T =
Gain term used to compensate span of Bridge reading
Offset term used to compensate offset of Bridge reading
Gain term used to compensate span of Temp reading
Offset term used to compensate offset of Temp reading
SOT =
the following:
1. Bridge measurement
Second Order Term. This term can be applied as a second order correction term for one of
2. Temperature coefficient of offset (Tco)
3. Temperature coefficient of gain (Tcg)
EEPROM bits 99:98 determine what SOT applies to.
TSETL
=
RAW_PTAT or ExtTemp reading (upper 7-bits) at low temperature at which calibration was
performed (typically at room temp)
Tcg =
Temperature correction coefficient of bridge gain term
This term has an 8-bit magnitude and a sign bit (Tc_cfg[2]).
1 Linear feedback shift register
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 26 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
Tco =
Temperature correction coefficient of bridge offset term
This term has an 8-bit magnitude, a sign bit (Tc_cfg[0]), and a scaling bit (Tc_cfg[1]) which
can multiply its magnitude by 8.
2.6.2 Interpretation of Binary Numbers for Correction Coefficients
BR_Raw should be interpreted as an unsigned number in the set [0,16383] with resolution of 1.
T_Raw should be interpreted as an unsigned number in the set [0,16383] with resolution of 4.
2.6.2.1 Gain_B Interpretation
Gain_B should be interpreted as a number in the set [0,64). The MSB (bit 14) is a scaling bit that will multiply
the effect of the Gain_B[13:0] term by 8. The remaining bits Gain_B[13:0] represent a number in the range of
[0,8) with Gain_B[13] having a weighting of 4, and each subsequent bit has a weighting of ½ the previous bit.
Table 2.2 – Gain_B Weightings
Bit Position
Weighting
13
12
11
.
4
2
1
.
.
1
2-10
2-11
0
Examples:
The binary number 010010100110001 = 4.6489. The scaling number is 0 so there is no multiplication by 8 of
the number represented by Gain_B[13:0].
The binary number 101100010010110 = 24.586. The scaling number is 1 so there is a multiplication by 8 of
the number represented by Gain_B[13:0].
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 27 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
2.6.2.2 Offset_B Interpretation
Offset_B is a 14-bit unsigned binary number. The MSB has a weighting of 8192. The following bits then have
a weighting of: 4096, 2048, 1024 …
Table 2.3 – Offset_B Weightings
Bit Position:
Weighting:
8192
13
12
11
.
4096
2048
.
.
1
21 = 2
20 = 1
0
For example, the binary number 11111111111100 = 4092.
2.6.2.3 Gain_T Interpretation
Gain_T should be interpreted as a number in the set [0,2). Gain_T[7] has a weighting of 1, and each
subsequent bit has a weighting of ½ the previous bit.
Table 2.4 – Gain_T Weightings
Bit Position
Weighting
7
6
5
.
1
0.5
0.25
.
.
1
0
2-6
2-7
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 28 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
2.6.2.4 Offset_T Interpretation
Offset_T is an 8-bit signed binary number in two’s complement form. The MSB has a weighting of –128. The
following bits then have a weighting of: 64, 32, 16 …
Table 2.5 – Offset_T Weightings
Bit Position
Weighting
-128
7
6
.
64
.
.
1
0
21 = 2
20 = 1
For example, the binary number 00101001 = 41.
2.6.2.5 Tco Interpretation
Tco is specified as having an 8-bit magnitude with an additional sign bit and a scalar bit (Tc_cfg). The scalar
bit when set multiplies the signed Tco by 8.
Tco Resolution: 0.175µV/V/oC
Tco Range:
+/- 44.6µV/V/oC (input referred)
If the scaling bit is used, then the above resolution and range are scaled by 8 to give the following:
Tco Scaled Resolution: 1.40µV/V/oC
(input referred)
+/- 357µV/V/oC (input referred)
(input referred)
Tco Scaled Range:
2.6.2.6 Tcg Interpretation
Tcg is specified as having an 8-bit magnitude with an additional sign bit (Tc_cfg).
Tcg Resolution: 17.0ppm/oC
Tcg Range:
+/- 4335ppm/oC
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 29 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
2.6.2.7 SOT Interpretation
SOT is a second order term that can apply to one and only one of the following: bridge non-linearity
correction, Tco non-linearity correction, or Tcg non-linearity correction.
As it applies to bridge non-linearity correction:
Resolution: 0.25% @ Full Scale
Range:
+25% @ Full Scale to -25% @ Full Scale
(Saturation in internal arithmetic will occur at greater negative non-linearities.)
As it applies to Tcg:
Resolution: 0.3 ppm/(oC)2
Range:
+/- 38ppm/(oC)2
As it applies to Tco:
2 settings are possible. It is possible to scale the effect of SOT by 8. If Tc_cfg[1] is set, then both Tco and
SOT’s contribution to Tco are multiplied by 8.
Resolution at unity scaling: 1.51nV/V/(oC)2
(input referred)
+/- 0.192μV/V/(oC)2 (input referred)
Range:
Resolution at 8x scaling:
Range:
12.1nV/V/(oC)2
+/- 1.54μV/V/(oC)2
(input referred)
(input referred)
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 30 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
2.7 Reading EEPROM Contents
The contents of the entire EEPROM memory can be read using the Read EEPROM Command (00H). This
command will cause the IC to output consecutive bytes on the ZACwireTM. The interpretation of these bytes is
given below:
Read EEPROM (Bit Order):
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Byte 1:
Byte 2:
Byte 3:
Byte 4:
Byte 5:
Byte 6:
Byte 7:
Byte 8:
Byte 9:
Byte 10:
Byte 11:
Byte 12:
Byte 13
Byte 14
Byte 15
Offset_B[7:0]
Gain_T[1:0]
Offset_B[13:8]
Gain_T[7:2]
Offset_T[1:0]
TSETL[1:0]
Offset_T[7:2]
Tcg[2:0]
TSETL[6:2]
Tco[2:0]
Tcg[7:3]
Tco[7:3]
Tc_cfg[2:0]
SOT[7:0]
Lock[0]
Diag_cfg[2:0]
SOT_cfg[3:0] *
Lock[2:1]
Up_Clip_Lim[6]
Up_Clip_Lim[5:0]
Low_Clip_Lim[6:0]
Cust_ID0[7:0]
Cust_ID1[7:0]
Cust_ID2[7:0]
Signature[7:0]
Byte 16: A2D_Offset[0]
1V_Trim[3:0] **
Osc_Trim[2:0]
A2D_Offset[3:1]
JFET_cfg[1] ***
Byte 17: JFET_cfg[0]*** Update_Rate[1:0]
Output Select[1:0]
Byte 18:
Byte 19:
Byte 20:
Gain_B[6:0]
Gain_B[14:7]
A5H
* SOT_cfg/Pamp_Gain
** IV_Trim/JFET_Trim
*** Config_JFET_Regulation
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 31 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
3
Application Circuit Examples
The minimum output analog load resistor is RL= 5kΩ. This optional load resistor can be configured as a pull-
up or pull-down. If it is configured as a pull-down, it cannot be part of the module to be calibrated because this
would prevent proper operation of the ZACwireTM. If a pull-down load is desired, it must be added to system
after module calibration.
There is no output load capacitance needed.
EEPROM contents: OUTPUT_select, Config_JFET_Regulation, 1V_Trim/JFET-Trim.
3.1 Three-Wire Rail-to-Rail Ratiometric Output
+2.7 to +5.5V
Vsupply
1 Bsink
2 VBP
VSS 8
SigTM
7
OUT
3 ExtTemp
4 VBN
VDD 6
Vgate 5
Optional
Bsink
0.1µF
Ground
Figure 3.1 – Rail-to-Rail Ratiometric Voltage Output, Temperature Compensation via External Diode
The optional bridge sink allows a power savings of bridge current. The output voltage can be either
a) Rail-to-rail ratiometric analog output VDD(=Vsupply).
b) 0 to 1V analog output. The absolute voltage output reference is trimmable 1V (+/-2mV) in the 1V Output
Mode via a 4-bit EEPROM field. See section 1.4.3.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 32 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
3.2 Absolute Analog Voltage Output
S
D
+5.5 to +30V
Vsupply
BSS169
1 Bsink
2 VBP
VSS 8
SigTM
7
OUT
3 ExtTemp
4 VBN
VDD 6
Vgate 5
Optional
Bsink
0.1µF
Ground
Figure 3.2 – Absolute Voltage Output with Temperature Compensation via Internal
Temperature PTAT with External JFET Regulation for all Industry Standard Applications
The output signal range is either
a) 0 to 1V analog output. The absolute voltage output reference is trimmable 1V (+/-2mV) in the 1V Output
Mode via a 4-bit EEPROM field.
b) Rail-to-rail analog output. The on-chip reference for the JFET regulator block is trimmable 5V (+/- ~10mV)
in the Ratiometric Output Mode via a 4-bit EEPROM field See section 1.4.3.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 33 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
3.3 Three-Wire Ratiometric Output with Over-Voltage Protection
S
D
+5 to +5.5 V
Vsupply
J107
Vishay
1 Bsink
2 VBP
VSS 8
SigTM
7
OUT
3 ExtTemp
4 VBN
VDD 6
Vgate 5
Optional
Bsink
0.1µF
Ground
Figure 3.3 – Ratiometric Output, Temperature Compensation via Internal Diode
In this application, the JFET is used for voltage protection. The Config_JFET_Regulation bits (16:15) in
EEPROM are configured to 5.5V. There is an additional maximum error of 8mV caused by the non-zero rON of
the limiter JFET.
3.4 Digital Output
For all three circuits, the output signal can also be digital. Depending on the output select bits, the bridge
signal or the bridge signal and temperature signal are sent.
For the digital output, no load resistor or load capacity is necessary. No pull down resistor is allowed. If a line
resistor or pull-up resistor is used, the requirement for the rise time must be met (< 5 μs). The IC output
includes an internal pull up resistor of about 30kΩ. The digital output can easily be read by firmware from a
microcontroller, and ZMD can provide the customer with software for developing the interface.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 34 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
3.5 Output Resistor/Capacitor Limits
The limits for external components depend on the programmed output mode:
•
•
•
Pure Analog Output Mode (calibration is done before)
The only limit is the minimum load resistance of 5kΩ
Pure Digital Output Mode with end-of-line calibration
The RC time constant of the ZACwire™ line must have a rise time < 5µs.
Analog output with digital communication during calibration
The RC time constant of the ZACwire™ line must have a rise time < 5µs.
Warning: Any series line resistance forms a voltage divider in conjunction with the pull-up load device.
If a series line resistance is needed, choose a low value relative to the pull-up load device.
4
ESD/Latch-Up-Protection
All pins have an ESD protection of >4000V and a latch-up protection of ±100mA or of +8V/ –4V (to
VSS/VSSA). ESD protection referenced to the Human Body Model is tested with devices in SOP-8 packages
during product qualification. The ESD test follows the Human Body Model with 1.5kOhm/100pF based on MIL
883, Method 3015.7.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 35 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
5
Pin Configuration and Package
8
7
6
1
2
3
4
5
Figure 5.1 – RBicdLiteTM Pin-Out Diagram
The standard package of the RBicdLiteTM is SOP-8 (3.81mm body (150mil) wide) with lead-pitch 1.27mm
(50mil).
Pin-No.
Name
Bsink
Description
Optional ground connection for bridge ground.
Used for power savings
1
2
3
4
VBP
Positive bridge connection
External diode connection
Negative bridge connection
ExtTemp
VBN
Gate control for external JFET regulation/over-
voltage protection
5
6
7
8
Vgate
VDD
SigTM
VSS
Supply voltage (2.7-5.5V)
ZACwireTM interface (analog out, digital out,
calibration interface)
Ground supply
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 36 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
6
IC Characteristics
6.1 Absolute Maximum Ratings
PARAMETER
SYMBOL MIN TYP
MAX
6.0
UNITS
VDD
VINA
Analog Supply Voltage
-0.3
-0.3
-0.3
-50
V
V
Voltages at Analog I/O – In Pin
Voltages at Analog I/O – Out Pin
VDDA+0.3
VDDA+0.3
150
VOUTA
TSTOR
V
°C
°C
Storage Temperature Range (≥10 hours)
TSTOR<10h
Storage Temperature Range (<10 hours)
-50
170
6.2 Recommended Operating Conditions
PARAMETER
SYMBOL MIN TYP
MAX
UNITS
Analog Supply Voltage to Gnd
VDD
2.7
5.5
-50
5.0
7
5.5
V
V
Analog Supply Voltage (with external JFET
Regulator)
VSUPP
30
Ambient Temperature Range 1&2
TAMB
CVDD
RL,OUT
CL,OUT
RBR
150
470
°C
nF
kΩ
nF
kΩ
ms
External Capacitance between VDDA and Gnd
100 220
3
Output Load Resistance to VSS or VDD
5
Output Load Capacitance4
10
15
Bridge Resistance
0.25
100
100
Power ON Rise Time
tPON
1Note that the maximum calibration temperature is 85°C.
2If buying die, designers should use caution not to exceed maximum junction temperature by proper package selection.
3Only needed for Analog Output Mode; not needed for Digital Output Mode. When using the output for digital calibration, no pull down
resistor is allowed.
4Using the output for digital calibration, CL,OUT is limited by the maximum rise time TZACrise. See section 6.3.
5Note: Minimum bridge resistance is only a factor if using the Bsink feature. The RDS(ON) of the Bsink transistor is 8 to 10Ω when
operating at VDD=5V. This does give rise to a ratiometricity inaccuracy that becomes greater with low bridge resistances.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 37 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
6.3 Electrical Parameters
PARAMETER
SYMBOL CONDITIONS
SUPPLY VOLTAGE / REGULATION
MIN
TYP
MAX
UNITS
Supply Voltage
VDD
IDD
2.7
5.0
250
5.5
V
At minimum update rate.
At maximum update rate.
Supply Current (varies with
update rate and output mode)
μΑ
1000
Temperature Coefficient –
PTAT Source
TCPTAT
20
100
2.6
ppm/K*
Power Supply Rejection Ratio
Power-On Reset Level
PSRR
POR
60
dB*
V
1.4
ANALOG TO DIGITAL CONVERTER (ADC)
rADC
14
Bit
Resolution
Integral Nonlinearity (INL)
Differential Nonlinearity (DNL)
INLADC
Based on ideal slope
-4
-1
+4
+1
LSB1
LSB*
DNLADC
ANALOG OUTPUT PARAMETERS (DAC + BUFFER)
Max current maintaining accuracy
Referenced to VDD
Max. Output Current
Resolution
IOUT
Res
2.2
mA
Bit
12
DAC input to output
No missing codes
Absolute Error
EABS
DNL
VOUT
VOUT
-10
-0.9
95%
+10
+1.5
mV
*
Differential Nonlinearity
Upper Output Voltage Limit
Lower Output Voltage Limit
LSB11Bit
VDD
RL =5Ω
2.5
mV
@5kΩ pull down, 0-1V output
DIAGNOSTICS
Upper diagnostic output level
Lower diagnostic output level
VDIA,H
VDIA,L
97.5%
5
VDD
VDD
2.5%
Pull-up or pull-down in Analog
Output Mode
Min Load Resistor for power loss
R L,OUT_PS
kΩ
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 38 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
PARAMETER
SYMBOL CONDITIONS
MIN
TYP
MAX
UNITS
EXTERNAL TEMPERATURE MEASUREMENT
ExtTemp Signal Input Range
VTSE
150
1.9
800
mV
Required External Temperature
Diode Sensitivity
STTSE
3.25
mV/K
Temperature Span with External
Temperature Diode
TTSE_SP
-50
150
1.5
°C
SYSTEM RESPONSE
tSTA
Startup time
ms
ms
Response Time for
Analog output
TRES,ADC
TRES, DIG
VNOISE,PP
Varies with update rate. Value
given at fastest rate.
1
Response and Transmission
Time for Digital Output
Varies with update rate. Value
given at fastest rate.
1.6
ms
Analog Output Noise
Peak-to-Peak
Shorted Input
5
mV
±1LSB
ZACwire™ Serial Interface*
See important limitations in
footnote 2 below.
ZACwire™ Line Resistance
ZACwire™ Load Capacitance
RZAC,line
CZAC,load
3.9
kΩ
See important limitations in
footnote 2 below.
0
1
15
nF
Voltage Level Low
Voltage Level High
VZAC_LOW
VZAC_HIGH
0.2
VDD
VDD
0
1
0.8
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 39 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
PARAMETER
SYMBOL CONDITIONS
TOTAL SYSTEM
MIN
TYP
MAX
UNITS
Power-up to output
Start-Up-Time
tSTA
tRESP
fS
5
2
ms
ms
Hz
mA
%
Update_rate=<1ms
Response Time
1
Update_rate=<1ms
Sampling Rate
1000
1
Update_rate=<1ms
Supply Current
IDD
1.5
Bridge input to output -- Digital
Bridge input to output -- Analog
Not using Bsink feature
Overall Linearity Error
Overall Linearity Error
Overall Ratiometricity Error
ELIND
ELINA
REout
0.02
0.1
TBD
TBD
TBD
%
0.035
%
-25°C to 85°C
-50°C to 150°C
±0.1%
%FSO
%FSO
Overall Accuracy – Digital
(only IC, without sensor bridge)
ACoutD
ACoutA
±0.25%
-25°C to 85°C
-40°C to 125°C
-50°C to 150°C
±0.25%
±0.35%
±0.5%
%FSO
%FSO
%FSO
Overall Accuracy – Analog 3
(only IC, without sensor bridge)
* The parameters with an * under “Units” are tested by design.
1 Note this is +/- 4 LSBs for the 14-bit A-to-D conversion. This results in absolute accuracy to 12-bits on the A-to-D result. Non-linearity is
typically better at temperatures less than 125°C.
2The rise time must be tZAC,rise = 2 RZAC,load * CZACload ≤ 5μs . If using a pull-up resistor instead of the line resistor, it must meet this
specification. The absolute maximum for CZACload is 15nF.
3 Not included is the quantization noise of the DAC. The 12-bit DAC has a quantization noise of ± ½ LSB = 0.61mV (5V VDD) = 0.125%.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 40 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
6.4 Analog Input versus Output Resolution
RBicdLiteTM has a fully differential chopper-stabilized pre-amplifier with 4 programmable gain settings. The
output of the pre-amplifier feeds into a 14-bit charge-balanced ADC. Span, offset, temperature, and non-
linearity correction are performed in the digital domain. Then the resulting corrected bridge value can be
output in analog form through a 12-bit DAC or as a 16-bit serial digital packet. The resolution of the output
depends on the input span (bridge sensitivity) and the analog gain setting programmed. Digital gains can vary
from [0,32). Analog gains available are 6, 24, 48, and 96.
Analog Gain = 24
Input Span (mV/V)
Typ Max
25.0
Allowed Offset
(+/- % of Span)1
Minimum Guaranteed
Resolution (Bits)
Min
18.0
33.0
26.6
19.8
13.2
7.9
17%
35%
12.7
12.4
12.0
11.4
10.7
10.1
9.4
14.5
10.8
7.2
20.0
15.0
10.0
6.0
70%
140%
280%
450%
750%
1400%
4.3
2.9
4.0
5.3
1.8
2.5
3.3
1.0
1.4
1.85
8.6
1In addition to Tco,Tcg
Analog Gain = 48
Input Span (mV/V)
Typ Max
15.0
Allowed Offset
(+/- % of Span)1
Minimum Guaranteed
Resolution (Bits)
Min
10.8
19.8
13.2
7.9
3%
35%
13
7.2
4.3
2.9
1.8
1.0
0.72
10.0
6.0
4.0
2.5
1.4
1.0
12.4
11.7
11.1
10.4
9.6
100%
190%
350%
675%
975%
5.3
3.3
1.85
1.32
9.1
1In addition to Tco,Tcg
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 41 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
Analog Gain = 96
Input Span (mV/V)
Typ Max
6.0
Allowed Offset
(+/- % of Span)1
Minimum Guaranteed
Resolution (Bits)
Min
4.3
7.9
20%
60%
12.7
12.1
11.4
10.6
10.1
2.9
4.0
2.5
1.4
1.0
5.3
1.8
3.3
140%
300%
450%
1.0
0.72
1.85
1.32
1In addition to Tco,Tcg
The preceding tables outline the guaranteed minimum resolution for a given bridge sensitivity range. This is
done for three different analog gain settings. At higher analog gain settings, there will be higher output
resolution, but the ability of the ASIC to handle large offsets decreases. This is expected since the offset is
also amplified by the analog gain and can therefore saturate the ADC input.
6.5 Temperature Compensation and Temperature Output
A highly linear bandgap/PTAT circuit is used to produce a signal which can be used in compensation of the
bridge over temperature. In addition, when Digital Mode is activated, both bridge and temperature signals (8-bit
temperature quantity) can be output on the ZACwireTM pin. The temperature signal is converted to 14-bit resolu-
tion internally. It is used at 12-bit resolution in compensating the bridge reading. It is only output in 8-bit resolu-
tion so that it can be contained in a single byte transmission over ZACwireTM. If the bridge is not near the
RBiccLite™, an external diode can be used for temperature measurement compensation. See section 1.2.1.
6.6 High Voltage Operation
A linear regulator control circuit is included on the IC to interface with an external JFET to allow for operation
in systems where the supply voltage exceeds 5.5V. This circuit can also be used for over-voltage protection.
The regulator set point has a coarse adjust (EEPROM bit) that can adjust the set point around 5.0 or 5.5V.
The 1V trim will also act as a fine adjustment for the regulation set point. Note: If using the external JFET for
over-voltage protection purposes (i.e., 5V at JFET drain and expecting 5V at JFET source), there will be a
voltage drop across the JFET so ratiometricity will be compromised somewhat depending on the RDS(ON) of
the chosen JFET. A Vishay J107 is the best choice that would produce only an 8mV drop worst case. If using
as regulation instead of over-voltage, a MMBF4392 also works well.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 42 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
7
Die Dimensions and Pad Coordinates
7.1 RBicdLite™ Die Dimensions
•
•
•
•
•
Die size (including scribeline):
Core die size (without scribeline):
Die thickness: 390µm
2468.5 µm x 1680.1 µm ≈ 4.15 mm2
2318.5 µm x 1530.1 µm ≈ 3.55 mm2
Scribeline (distance between two core dice on wafer): 150µm
Pads size: 68µm x 68µm
85.9μm
7.2 RBicdLite™ Pad Coordinates
All pads coordinates are
for pad centers and related
to the corner.
vss
vssa
bsink
vpp
ZMD31015
por_n
vbp
2318.5μm
sig_pd
vdd
ExtTemp
sig_pd_diag
y
vbn
vdd
x
vgate
Figure 7.1 – RBicdLiteTM Core Die with Pads
1530.1μm
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 43 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
Position in μ
Pad Name
Comments
X
Y
bsink
por_n
vbp
106.3
85.9
Open, if not used.
1109.7
1356.4
1450.0
1628.1
1806.9
107.2
85.9
Internal (Not for customer use.)
VBP
85.9
vdd
77.3
Additional VDD (Internally connected.)
External temperature signal; open if not used.
VBN
ExtTemp
vbn
79.0
85.9
vss
1444.7
1444.7
1444.7
1444.7
1444.7
1435.8
1444.7
VSS must be connected.
VSS analog must be connected.
Internal (Not for customer use.)
SIG™
vssa
198.3
vpp
356.1
sig_pd
sig_pd_diag
vdd
1428.6
1674.6
1911.1
2048.0
Short to sig_pd for power loss detection.
VDD must be connected.
Open if not used.
vgate
7.3 Bonding Requirements
When bonding RBicdLite™ die, always use bond wires with a thickness of 25 µm (1 mil) and a bond tool with a
diameter of approximately 40 µm (1.5 mil) in diameter.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 44 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
8
Test
The test program is based on this datasheet. The final parameters which will be tested during series
production are listed in the tables of section 6.3.
The digital part of the IC includes a scan path, which can be activated and controlled during wafer test. It
guarantees failure coverage of more than 98%. Further test support for testing of the analog parts on wafer
level is included in the DSP.
9
Reliability
A reliability investigation according to the in-house non-automotive standard will be performed.
10 Customization
For high-volume applications, which require an upgraded or downgraded functionality compared to the
ZM31010, ZMD can customize the circuit design by adding or removing certain functional blocks.
For this customization, ZMD has a considerable library of sensor-dedicated circuitry blocks, which enable
ZMD to provide a custom solution quickly. Please contact ZMD for further information.
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 45 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
ZMD31015
RBicdLiteTM Low-Cost Sensor Signal Conditioner with Diagnostics
Datasheet
PRELIMINARY
11 Related Documents
For the most recent revisions of this document and of the related documents, please go to www.zmd.biz
•
•
•
ZMD31015 RBicLiteTM Die Dimensions and Pad Coordinates t
ZMD31015 RBicLiteTM Development Kit Documentation
ZMD31010 RBicLiteTM Application Notes – In-Circuit Programming Boards
For the most recent revisions of this document and of the related documents, please go to www.zmd.biz . This information applies to a
product under development. Its characteristics and specifications are subject to change without notice. ZMD assumes no obligation
regarding future manufacture unless otherwise agreed in writing. The information furnished hereby is believed to be correct and accurate.
However, ZMD shall not be liable to any customer, licensee or any other third party for any damages in connection with or arising out of
the furnishing, performance or use of this technical data. No obligation or liability to any customer, licensee or any other third party shall
result from ZMD’s rendering of technical or other services.
ZMD AG
Grenzstrasse 28
ZMD America, Inc.
ZMD Far East
For further
information:
201 Old Country Road, Suite 204 1F, No.14, Lane 268
01109 Dresden, Germany
Phone +49 (0)351-8822-366
Fax +49 (0)351-8822-337
Melville, NY 11747, USA
Phone +01 (631) 549-2666
Fax +01 (631) 549-2882
sales@zmda.com
Sec. 1 Guangfu Road
HsinChu City 300
Taiwan
sales@zmd.de
www.zmd.biz
Phone +886.3.563.1388
Fax +886.3.563.6385
www.zmd.biz
sales@zmd.de
www.zmd.biz
Preliminary Datasheet, Rev. 0.6, October 23, 2006
Page 46 of 46
© ZMD AG, 2006
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior
written consent of the copyright owner. The Information furnished in this publication is preliminary and subject to changes without notice.
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