Data Sheet

Data Sheet
Rev. 1.02 / May 2012
ZSSC3026
Low Power, High Resolution 16-Bit Sensor Signal Conditioner
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Brief Description
Benefits
The ZSSC3026 is a sensor signal conditioner
(SSC) integrated circuit for high-accuracy amplification and analog-to-digital conversion of a differential input signal. Designed for high resolution
altimeter module applications, the ZSSC3026 can
st
nd
perform offset, span, and 1 and 2
order
temperature compensation of the measured signal.
Developed for correction of resistive bridge
sensors, it can also provide a corrected
temperature output measured with an internal
sensor.
•
The measured and corrected bridge values are
provided at the digital output pins, which can be
2
configured as I C* (≤ 3.4MHz) or SPI (≤ 20MHz).
Digital compensation of signal offset, sensitivity,
temperature, and non-linearity is accomplished via
an 18-bit internal digital signal processor (DSP)
running a correction algorithm. Calibration coefficients are stored on-chip in a highly reliable, nonvolatile, multiple-time programmable (MTP) memory. Programming the ZSSC3026 is simple via the
serial interface. The IC-internal charge pump
provides the MTP programming voltage. The
interface is used for the PC-controlled calibration
procedure, which programs the set of calibration
coefficients in memory. The digital mating is fast
and precise, eliminating the overhead normally
associated with trimming external components and
multi-pass calibration routines.
Features
•
•
•
•
•
•
•
•
*
Flexible, programmable analog front-end
design; up to 16-bit scalable, charge-balancing
two-segment analog-to-digital converter (ADC)
Fully programmable gain amplifier accepting
sensors from 14 to 72 (linear factor)
Internal auto-compensated temperature sensor
Digital compensation of individual sensor offset;
st
nd
1 and 2 order digital compensation of sensor
gain
st
nd
Digital compensation of 1 and 2 order temperature gain and offset drift
Intelligent power management unit
Layout customized for die-die bonding with
sensor for high-density chip-on-board assembly
Typical sensor elements can achieve accuracy
of less than ±0.10% FSO @ -40 to 110°C
•
•
•
•
•
Integrated 18-bit calibration math DSP
Fully corrected signal at digital output
Minimize calibration costs through the one-pass
calibration concept
No external trimming components required
Highly integrated CMOS design
Excellent for low-voltage and low-power battery
applications
Physical Characteristics
•
•
•
•
•
•
•
Supply voltage range: 1.8 to 3.6V
Current consumption: 1mA (operating mode)
Sleep State current: 50nA (typical)
Temperature resolution: <0.003K/LSB
Operation temperatures: –40°C to +85°C
–40°C to +110°C
Small die size: 1.5mm²
Delivery options: die for wafer bonding,
bumped die for Flip Chip, PQFN24
Typical Applications
The ZSSC3026 is designed for operation in
calibrated resistive (pressure) sensor modules:
•
•
•
•
•
•
Barometric altitude measurement for portable
navigation
Altitude measurement for emergency call
systems
Altitude measurement for car navigation
Inside hard disk pressure measurement
Weather forecast
Fan control
ZSSC3026 Application Example.
2
I C is a registered trademark of NXP.
© 2012 ZMD AG — Rev. 1.02
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.
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
ZSSC3026 Block Diagram
Ordering Information
Ordering Examples *
Description
Package
ZSSC3026CC1B
Temperature range: –40°C to +85 °C,
Consumer-Level: Parameter according Data Sheet
Chips, Wafer (304um) unsawn, tested
ZSSC3026CI1B
Temperature range: –40°C to +85 °C,
Industrial-Level: 10 years MTP-Data Retention
Chips, Wafer (304um) unsawn, tested
ZSSC3026CI4
Temperature range: –40°C to +110 °C, Industrial
PQFN24 4x4, tested
ZSSC30x6KIT
Evaluation Kit for ZSSC30x6 Product Family
Boards, cable, software-CD, 1 sample
* Please contact ZMDI Sales for additional options.
Sales and Further Information
www.zmdi.com
[email protected]
Zentrum Mikroelektronik
Dresden AG
Zentrum Mikroelektronik
Dresden AG, Japan Office
ZMD FAR EAST, Ltd.
ZMD America, Inc.
Grenzstrasse 28
01109 Dresden
Germany
8413 Excelsior Drive
Suite 200
Madison, WI 53717
USA
Phone
Fax
Phone
Fax
+49 (0)351.8822.7.772
+49 (0)351.8822.87.772
+1 (608) 829-1987
+1 (631) 549-2882
2nd Floor, Shinbashi Tokyu Bldg.
4-21-3, Shinbashi, Minato-ku
Tokyo, 105-0004
Japan
Phone
Fax
+81.3.6895.7410
+81.3.6895.7301
3F, No. 51, Sec. 2,
Keelung Road
11052 Taipei
Taiwan
Phone
Fax
+886.2.2377.8189
+886.2.2377.8199
DISCLAIMER: This information applies to a product under development. Its characteristics and specifications are PRELIMINARY and subject to change without notice. Zentrum
Mikroelektronik Dresden AG (ZMD AG) assumes no obligation regarding future manufacture unless otherwise agreed to in writing. The information furnished hereby is believed to be true
and accurate. However, under no circumstances shall ZMD AG be liable to any customer, licensee, or any other third party for any special, indirect, incidental, or consequential damages of
any kind or nature whatsoever arising out of or in any way related to the furnishing, performance, or use of this technical data. ZMD AG hereby expressly disclaims any liability of ZMD AG
to any customer, licensee or any other third party, and any such customer, licensee and any other third party hereby waives any liability of ZMD AG for any damages in connection with or
arising out of the furnishing, performance or use of this technical data, whether based on contract, warranty, tort (including negligence), strict liability, or otherwise
© 2012 ZMD AG — Rev. 1.02
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.
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Table of Contents
1
2
IC Characteristics .......................................................................................................................................... 7
1.1.
Absolute Maximum Ratings.................................................................................................................... 7
1.2.
Operating Conditions.............................................................................................................................. 7
1.3.
Electrical Parameters ............................................................................................................................. 8
1.4.
Power Supply Rejection Ratio vs. Frequency ...................................................................................... 10
Circuit Description ....................................................................................................................................... 11
2.1.
Brief Description ................................................................................................................................... 11
2.2.
Signal Flow and Block Diagram ........................................................................................................... 11
2.3.
Analog Front End ................................................................................................................................. 12
2.3.1.
Amplifier ......................................................................................................................................... 12
2.3.2.
Analog-to-Digital Converter ........................................................................................................... 14
2.3.3.
Temperature Measurement ........................................................................................................... 17
2.3.4.
Bridge Supply................................................................................................................................. 17
2.4.
3
Digital Section....................................................................................................................................... 17
2.4.1.
Digital Signal Processor (DSP) Core ............................................................................................. 17
2.4.2.
MTP Memory ................................................................................................................................. 17
2.4.3.
Clock Generator............................................................................................................................. 18
2.4.4.
Power Supervision ......................................................................................................................... 18
2.4.5.
Interface ......................................................................................................................................... 18
Functional Description................................................................................................................................. 19
3.1.
Power Up.............................................................................................................................................. 19
3.2.
Measurements...................................................................................................................................... 19
3.3.
Operational Modes ............................................................................................................................... 19
3.4.
Command Interpretation....................................................................................................................... 21
3.4.1.
3.5.
SPI/I2C Commands ....................................................................................................................... 21
Communication Interface ..................................................................................................................... 23
3.5.1.
Common Functionality ................................................................................................................... 23
3.5.2.
SPI ................................................................................................................................................. 25
3.5.3.
I C .................................................................................................................................................. 27
3.6.
2
Memory................................................................................................................................................. 28
3.6.1.
Programming Memory ................................................................................................................... 28
3.6.2.
Memory Status Commands ........................................................................................................... 29
3.6.3.
Memory Contents........................................................................................................................... 30
3.7.
Calibration Sequence ........................................................................................................................... 36
3.7.1.
Calibration Step 1 – Assigning Unique Identification..................................................................... 36
3.7.2.
Calibration Step 2 – Data Collection.............................................................................................. 36
3.7.3.
Calibration Step 3 – Coefficient Calculations ................................................................................ 37
3.8.
The Calibration Math ............................................................................................................................ 37
3.8.1.
Data Sheet
May 15, 2012
Bridge Signal Compensation ......................................................................................................... 37
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
4 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
3.8.2.
4
Temperature Signal Compensation ............................................................................................... 40
Die Dimensions and Pin Assignments ........................................................................................................ 41
4.1.
Package (PQFN24) Properties............................................................................................................. 43
5
Quality and Reliability..................................................................................................................................44
6
Related Documents..................................................................................................................................... 45
7
Glossary ...................................................................................................................................................... 45
8
Document Revision History......................................................................................................................... 46
Table of Figures
Figure 2.1
ZSSC3026 Functional Block Diagram........................................................................................... 11
Figure 2.2
ADC Offset..................................................................................................................................... 16
Figure 3.1
Operational Flow Chart: Power up. ............................................................................................... 20
Figure 3.2
Operational Flow Chart: Command Mode and Normal Mode. ...................................................... 21
Figure 3.3
SPI configuration CPHA=0. ........................................................................................................... 25
Figure 3.4
SPI Configuration CPHA=1. .......................................................................................................... 25
Figure 3.5
SPI Command Request................................................................................................................. 26
Figure 3.6
SPI Read Status. ........................................................................................................................... 26
Figure 3.7
SPI Read Data............................................................................................................................... 26
Figure 3.8
I C Command Request................................................................................................................. 27
Figure 3.9
2
I2C Read Status. .......................................................................................................................... 27
2
Figure 3.10 I C Read Data................................................................................................................................ 28
Figure 3.11 Memory Program Operation. ......................................................................................................... 29
Figure 4.1
ZSSC3026 Pad Placement............................................................................................................ 41
Figure 4.2
General PQFN24 Package Dimensions. ....................................................................................... 43
List of Tables
Table 1.1
Maximum Ratings. ........................................................................................................................... 7
Table 1.2
Operating Conditions. ...................................................................................................................... 7
Table 1.3
Constraints for VDD Power-on Reset.............................................................................................. 7
Table 1.4
Electrical Parameters. ..................................................................................................................... 8
Table 2.1
Amplifier Gain: Stage 1.................................................................................................................. 12
Table 2.2
Amplifier Gain: Stage 2.................................................................................................................. 12
Table 2.3
Gain Polarity. ................................................................................................................................. 13
Table 2.4
MSB/LSB Settings. ........................................................................................................................ 14
Table 2.5
ADC Conversion Times for a single A2D conversion.................................................................... 14
Table 2.6
Conversion Times vs. Noise Performance for 16bit fully Signal Conditioned Results
(AZBM, BM, AZTM, TM and digital SSC correction). ................................................................... 15
Table 2.7
ADC Offset Settings. ..................................................................................................................... 16
Table 3.1
SPI/I2C Commands....................................................................................................................... 22
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
5 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Table 3.2
Get_Raw Commands. ................................................................................................................... 23
Table 3.3
General Status Byte. ..................................................................................................................... 24
Table 3.4
Status Byte for Read Operations................................................................................................... 24
Table 3.5
Status Byte for Write Operations. .................................................................................................. 24
Table 3.6
Mode Status................................................................................................................................... 24
Table 3.7
Memory Status Word..................................................................................................................... 29
Table 3.8
MTP Memory Content Assignments.............................................................................................. 30
Table 4.1
Die Size & Geometry. .................................................................................................................... 41
Table 4.2
Pin Assignments. ........................................................................................................................... 42
Table 4.3
Physical Package Dimensions’ Extrema. ...................................................................................... 43
Table 4.4
Pin Assignments PQFN24............................................................................................................. 44
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
6 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
1
IC Characteristics
1.1.
Absolute Maximum Ratings
Table 1.1
Maximum Ratings.
PARAMETER
SYMBOL
Min
Voltage Reference
Vss
Analog Supply Voltage
Voltage at all Analog and Digital IO Pins
1
Input Current into any Pin except SDA, CLK and Supply Pins
2
Electrostatic Discharge Tolerance – Human Body Model (HBM1)
Storage Temperature
1
2
3
3
TYP
MAX
UNITS
0
0
V
VDD
-0.4
3.63
V
VA_IO, VD_IO
-0.5
VDD+0.5
V
Iin
-100
100
mA
VHBM1
4000
-
V
TSTOR
-50
125
°C
Latch-up current limit for CLK/SCLK and MOSI/SDA: ±70mA.
Latch-up resistance; reference for pin is 0V.
HBM1: C = 100pF charged to VHBM1 with resistor R = 1.5kΩ in series based on MIL 883, Method 3015.7. ESD protection
referring to the Human Body Model is tested with devices in ceramic dual in-line packages (CDIP) during product qualification.
1.2.
Operating Conditions
Reference for all voltages is Vss.
Table 1.2
Operating Conditions.
PARAMETER
SYMBOL
MIN
TYP
MAX
UNIT
Supply Voltage
VDD
1.8
-
3.6
V
VDD Rise Time
tVDD
200
µs
Bridge Current
IVDDB
600
µA
Operation Temperature Range*
Tamb
-40
125
°C
CL
0.01
50
nF
External capacitance between VDDB and VSS
-
* Temperature sensor’s operation and output only up to 110°C (for respective IC version).
In order to achieve minimum current consumption in idle mode, a dynamic power-on-reset circuit is implemented.
The VDD low level and the subsequent rise time and VDD rising slope have to fulfill specific constraints to
guarantee an overall IC reset, respectively.
Generally it holds: lower VDD low levels allow for slower rising of the subsequent on-ramp of VDD. The following
table shows the relevant reset parameters and conditions. Other combinations may also be possible. The reset
trigger can be influenced by increasing the power down time and relaxing, e.g. the VDD rising slope requirement.
Table 1.3
Constraints for VDD Power-on Reset.
PARAMETER
SYMBOL
MIN
TYP
MAX
UNIT
tSPIKE
3
-
-
µs
VDD Low Level
VDDlow
0
-
0.2
V
VDD Rising Slope
SRVDD
10
-
-
V/ms
Power Down Time (duration of VDD Low Level)
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
7 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
1.3.
Electrical Parameters
All parameter values are valid only under specified operating conditions. All voltages are referenced to Vss.
Table 1.4
Electrical Parameters.
PARAMETER
SYMBOL
CONDITIONS/COMMENTS
MIN
TYP
MAX
UNIT
1.60
1.67
1.74
V
Active State, average
900
1500
µA
Sleep State, Idle Current, <85°C
20
250
nA
Sleep State, Idle Current, <125°C
50
950
nA
SUPPLY
Bridge Supply Voltage,
ADC Reference Voltage
Current Consumption
VDDB
IVDD
Power Supply Rejection
(see Figure 3.1)
20·log10(VDD/VDDB)
PSRVDD
Memory Program Voltage
internally generated
where VDD = 1.8V
17
dB
where VDD = 2V
32
dB
VDD,prog
Required voltage level at VDD-pin
2.9
Mean Program Current
IVDD,Prog
Mean current consumption during
MTP programming cycle at VDD
6
Peak Program Current
Iprog,max
MTP Program at VDD-pin,
dynamic switch-on current draw
3.6
V
mA
20
mA
16
Bit
ANALOG TO DIGITAL CONVERTER (ADC)
Resolution
rADC
10
ADC Clock Frequency
fADC
Reference Voltage n
Vrefn
VDDB
*0.03
Reference Voltage p
Vrefp
VDDB
*0.97
Offset
A2D_Offset
8-step programmable offset
Integral Nonlinearity (INL)
INLADC
Based on ideal slope
-4
-
+4
LSB
Differential Nonlinearity
DNLADC
Tested / verified within design
-1
-
+1
LSB
Conversion Rate, 16bit single
fS,raw
Conversions per second for
single 16bit A2D conversion
6
-
355
Hz
Internal ADC clock
0.925
1
1/16
1.12
MHz
8/16
AMPLIFIER
Gain
Gamp
32 steps
13.2
Gain Error
Gerr
referred to nominal gain
-1.5
72
-
1.5
%
0.01
%FSO
SENSOR SIGNAL CONDITIONING PERFORMANCE
IC Accuracy Error
*
ErrA,IC
Accuracy error for ideally linear
(in temperature and e.g.
pressure) sensor
*
Percentage referred to maximum full-scale output, e.g. for 16bit measurements: ErrA,IC [%FSO] = 100 · MAX{ | ADCmeas – ADCideal | } / 216
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
8 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
PARAMETER
Conversion Rate, 16bit SSC
SYMBOL
fS, SSC
CONDITIONS/COMMENTS
MIN
TYP
MAX
Conversion per second for fully
corrected 16bit measurement
3
175
0.65
1.05
UNIT
Hz
INPUT
Input Voltage Range
VINP, VINN
Bridge Resistance
RBR
Input voltage range at INP and
INN
2
10
V
50
kΩ
1
ms
2.5
ms
0.5
ms
2
ms
4.4
MHz
POWER UP
VDD ramp up to interface
communication
VDD ramp up to analog
operation
Sleep to Active State interface
communication
Sleep to Active State analog
operation
tSTA1
Start-up Time
tSTA2
tWUP1
Wake-up Time
tWUP2
OSCILLATOR
Internal Oscillator
Frequency
fCLK
3.6
4
INTERNAL TEMPERATURE SENSOR
for both ranges:
-40°C to +85°C
-40°C to +110°C
Temperature Resolution
0.003
K/LSB
INTERFACE and MEMORY
*
SPI Clock Frequency
fC,SPI
I²C Clock Frequency
fC,I2C
Program Time
tprog
Data Retention
tRET_MTP
max. capacitance at MISO-line:
40pF @ VDD=1.8V
MTP programming time per
register
for industrial-level IC-version:
1000h @ 125°C
500
10
*
20
MHz
3.4
MHz
600
µs
a
with maximum ambient temperature of 125°C
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
9 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
1.4.
Power Supply Rejection Ratio vs. Frequency
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
10 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
2 Circuit Description
2.1.
Brief Description
The ZSSC3026 provides a highly-accurate amplification of bridge sensor signals. The compensation of sensor
offset, sensitivity, temperature drift, and non-linearity is accomplished via an 18-bit DSP core running a correction
algorithm with calibration coefficients stored in an MTP memory. The ZSSC3026 can be configured for a wide
2
range of resistive bridge sensor types. A digital interface (SPI or I C) enables communication. The ZSSC3026
supports two operational modes: Normal Mode and Command Mode. Normal Mode is supposed to be the mode
being used typically, in which the IC wakes up from a Sleep (low power) State, runs a measurement in Active
State and turns back automatically to the Sleep State.
2.2.
Signal Flow and Block Diagram
See Figure 2.1 for the ZSSC3026 block diagram. The sensor bridge supply VDDB and the power supply for analog
circuitry are provided by a voltage regulator, which is optimized for power supply disturbance rejection (PSRR).
See section 1.4 for a graph of PSRR versus frequency. To improve noise suppression, the digital blocks are
powered by a separate voltage regulator. A power supervision circuit monitors all supply voltages and generates
appropriate reset signals for initializing the digital blocks.
The state machine controls the analog circuitry to perform the three measurement types: bridge, temperature, and
offset measurement. The multiplexer selects the signal input to the amplifier, which can be the external signals
from the input pins INP and INN, the internal temperature reference sensor signals, or an input short for
measuring offset. A full measurement request will trigger an automatic sequence of all measurement types and all
input signals, respectively. The Temperature Reference Sensor block is based on a PTAT temperature sensor.
The inherit (IC-fabrication related) device mismatch is suppressed by dynamic element matching technique.
Figure 2.1 ZSSC3026 Functional Block Diagram.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
11 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
The amplifier consists of two stages with programmable gain values. The 1/f noise and inherent offset are
suppressed by auto-zero and chopper stabilizer techniques. This auto-zero sequence is performed before each
bridge sensor and temperature measurement to compensate for the inherent offset of the amplifier.
The ZSSC3026 employs a charge-balancing analog-to-digital converter (ADC) based on switched-capacitor
technique with inherit low-pass behavior and noise suppression. The programmable resolution from 10 to 16 bit
provides flexibility for adapting the conversion characteristics. To improve power supply noise suppression, the
ADC uses the bridge supply VDDB as its reference voltage.
The remaining IC-internal and the sensor element offset i.e., the overall system offset (amplifier and ADC) can be
canceled by an offset and auto-zero measurement, respectively.
st
nd
The DSP accomplishes the auto-zero, span, and 1 and 2 order temperature compensation of the measured
bridge signal. The correction coefficients are stored in the MTP memory.
2
The ZSSC3026 supports SPI and I C interface communication for controlling, configuration and measurement
result output.
2.3.
Analog Front End
2.3.1. Amplifier
The amplifier has a differential architecture and consists of two stages. The amplification of each stage and the
sensor bridge gain polarity are programmable via settings in the Measurement Configuration Register
(BM_config) in the MTP memory (see section 2.4.2).
The first five bits of BM_config are the programmable gain settings Gain_stage1 and Gain_stage2. The options
for the programmable gain settings are listed in Table 2.1 and Table 2.2.
Table 2.1
Amplifier Gain: Stage 1.
Gain_stage1
Bit G1
Bit G0
Stage 1 Gain Setting
0
0
12
0
1
20
1
0
30
1
1
40
Table 2.2
Amplifier Gain: Stage 2.
Gain_stage2
Bit G4
Bit G3
Bit G2
Stage 2 Gain Setting
0
0
0
1.1
0
0
1
1.2
0
1
0
1.3
0
1
1
1.4
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
12 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Gain_stage2
Bit G4
Bit G3
Bit G2
Stage 2 Gain Setting
1
0
0
1.5
1
0
1
1.6
1
1
0
1.7
1
1
1
1.8
If needed, the polarity of the sensor bridge gain can be reversed by setting the Gain_Polarity bit in the BM_config
register (see section 2.4.2). Changing the gain polarity is achieved by inverting the chopper clock. Table 2.3 gives
the settings for the Gain_Polarity bit. This feature enables to apply a sensor to the ZSSC3026 with swapped input
signals at INN and INP e.g., to avoid crossing wires for the final sensor module’s assembly.
Table 2.3
Gain Polarity.
Gain_Polarity Bit
Gain
Setting Description
0
+1
No polarity change.
1
-1
Gain polarity is inverted.
The inherent amplifier offset is suppressed by means of auto zero and chopper techniques.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
13 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
2.3.2. Analog-to-Digital Converter
A second-order charge-balancing analog-to-digital converter (ADC) is used to convert the amplifier signal. To
allow optimizing the trade-off between conversion time and resolution, the conversion is split into a MSB coarse
conversion and an LSB fine conversion. The MSB-LSB segmentation is programmable via the Msb and Lsb
settings in the BM_config register stored in the MTP memory (see section 2.4.2). The final ADC resolution is
MSB
LSB
determined by MSB+LSB. The conversion time is proportional to 2
+2 . During the MSB coarse conversion,
MSB
the ADC input signal is sampled and integrated 2
times, resulting in inherit low-pass behavior and noise
suppression; here it holds: the longer the MSB coarse conversion, the better the noise suppression. Possible
settings are listed in Table 2.4.
Table 2.4
MSB/LSB Settings.
Msb Setup Bits
in BM_config
Number of MSB Coarse
Conversion Bits
Lsb Setup Bits
in BM_config
Number of LSB Fine
Conversion Bits
00BIN
10
00BIN
0
01BIN
12
01BIN
2
10BIN
14
10BIN
4
11BIN
16
11BIN
7
Useful MSB/LSB setups are with LSB = 0 (MSB-only conversions) or combinations of MSB > LSB with
MSB + LSB ≤ 16. Resolutions beyond 16-bit mainly digitize the collected front-end noise and typically do not
improve the system performance. MSB/LSB segmentations with LSB > MSB are also not useful because typically
the resolution remains the same as with the inverse MSB/LSB segmentation but the noise performance becomes
significantly worse yet the required conversion time stays the same. The ADC conversion times for different
MSB/LSB settings are listed in Table 2.5.
Table 2.5
ADC Conversion Times for a single A2D conversion.
MSB
[Bit]
LSB
[Bit]
10
0
1169
12
0
4625
14
0
18449
16
0
73745
10
2
1176
12
2
4632
14
2
18456
10
4
1200
12
4
4656
10
6
1296
Data Sheet
May 15, 2012
Bridge & Temperature Measurement
Conversion Time in µs
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
14 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Table 2.6
Conversion Times vs. Noise Performance for 16bit fully Signal Conditioned Results
(AZBM, BM, AZTM, TM and digital SSC correction).
ADC Segmentation:
Temperature Sensor
[MSB/LSB]
ADC Segmentation:
Bridge Sensor
[MSB/LSB]
Measurement Duration,
MEASURE (ACHEX)
[ms]
3-sigma Noise for SSC†
corrected Output
[counts]
10 / 6
10 / 6
5.8
8.6
10 / 6
12 / 4
13.2
6.4
10 / 6
14 / 2
43.0
5.8
10 / 6
16 / 0
164.1
5.6
*
10 / 6
13.2
8.4
*
12 / 4
20.5
6.4
*
14 / 2
50.5
5.6
*
12 / 4
16 / 0
170.3
5.1
14 / 2
10 / 6
43.0
7.6
14 / 2
12 / 4
50.5
5.9
14 / 2
14 / 2
80.7
4.4
14 / 2
16 / 0
200.3
4.4
16 / 0
10 / 6
162.6
6.9
16 / 0
12 / 4
170.3
5.4
16 / 0
14 / 2
200.3
4.1
16 / 0
16 / 0
319.5
4.0
12 / 4
12 / 4
12 / 4
†
*
Reference noise values obtained with setup: 13.7kOhm sensor bridge, 25°C, Gain=64, ADC-shift=-1/16…15/16, VDD=1.8V .
ZMDI-recommendation for temperature sensor measurement’s ADC segmentation.
Data Sheet
May 15, 2012
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
15 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
The ADC offset is programmable in 8 steps so that the ADC input voltage range can be adapted to the voltage
range at the input pins INP and INN. Possible ADC input voltages are shown in Figure 2.2, where VAGND = VDDB/2.
The ADC offset is controlled by the A2D_Offset setting in the Measurement Configuration Register (BM_config) in
the MTP memory (see section 2.4.2). The ADC offset settings are listed in Table 2.7.
Figure 2.2 ADC Offset.
Table 2.7
ADC Offset Settings.
Z2
Z1
Z0
ADC Differential Input Range/Vref
Where Vref = Vrefp - Vrefn
A2D_Offset
0
0
0
-1/16 to 15/16
1/16
0
0
1
-2/16 to 14/16
2/16
0
1
0
-3/16 to 13/16
3/16
0
1
1
-4/16 to 12/16
4/16
1
0
0
-5/16 to 11/16
5/16
1
0
1
-6/16 to 10/16
6/16
1
1
0
-7/16 to 9/16
7/16
1
1
1
-8/16 to 8/16
8/16
Data Sheet
May 15, 2012
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
16 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
2.3.3. Temperature Measurement
The ZSSC3026 provides an internal temperature sensor measurement to allow compensation for temperature
effects. See section 1.3 for the temperature sensor resolution. The temperature sensor uses bipolar transistors.
Any transistor circuitry mismatch is suppressed by dynamic element matching technique. The temperature output
signal is a differential voltage that is adapted by the amplifier for the ADC input.
For temperature measurements, the ADC offset and amplifier gain setting are defined by ZMDI. The ADC
MSB/LSB segmentation is programmable by the user for optimizing resolution or conversion time (see section
2.3.2).
2.3.4. Bridge Supply
The ZSSC3026 provides dedicated bridge supply pins VDDB and VSSB. The ADC reference voltages for the
sensor bridge measurement are derived from these internal voltages so that bridge supply disturbances are
suppressed. The current drive ability of VDDB is limited (see IVDDB in section 1.2).
2.4.
Digital Section
2.4.1.
Digital Signal Processor (DSP) Core
The DSP Core block performs the algorithm for correcting the sensor signal. The resulting coefficients are stored
in the MTP memory. When the measurement results are available, the "end of conversion" signal is set at the
EOC pin. The internal EOC information is valid only if both the measurement and calculation have been
completed.
2.4.2.
MTP Memory
The ZSSC3026’s memory is designed with an OTP (one-time programmable) structure. The memory is organized
in 4 one-time programmable pages. When data in the currently valid memory page has to be updated, normally a
new page must be selected by increasing the page counter and the whole memory content has to be written in its
updated version. The user has access to a 24 x 16 bit storage area for values such as calibration coefficients.
Dedicated calibration values are stored in an area not accessible to the user. The required programming voltage
is generated IC-internally whereas increased IC power supply requirements have to be fulfilled during
programming (see Memory Programming Voltage in section 1.3). There is no over-write or erase function for the
MTP memory.
The physical memory function is such that each single bit which has not yet been set to 1 (so, still being 0) can be
changed to 1, still. So, it is possible to (partially) re-program an MTP-register, e.g.:
•
Assume MTP-address 11HEX was written with 8421HEX which is 1000 0100 0010 0001binary.
•
due to whatever reason there would be the need to change the register content to A6A7HEX which is
1010 0110 1010 0111binary. This can be achieved by either writing A6A7HEX (any already written bit will
be ignored automatically) or just writing the difference to 8421HEX, which is 2286HEX.
The content of a re-written register can generally be determined by:
contentRegister = contentold (BITWISE_OR) contentnew.
If contentRegister equals contentnew, a re-write is possible – this is, e.g. not the case for contentold = FFFFHEX and
contentnew ≠ FFFFHEX. Or, in other words, depending on the former and the newly intended MTP-address and
register content a re-programming could be possible.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
17 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
2.4.3.
Clock Generator
The clock generator provides a 4MHz clock signal. The frequency is trimmed during production test.
2.4.4.
Power Supervision
The Power Supervision block monitors all power supplies to ensure a defined reset of all digital blocks during
power-up or power supply interruptions.
2.4.5.
Interface
2
*
The ZSSC3026 can communicate with the user’s PC via an SPI or I C interface . The interface type is selectable
via the voltage level on the SEL pin:
• SEL = 0 -> SPI Mode
• SEL = 1 -> I2C Mode
If the SEL pin is not connected, I²C communication will be selected (IC-internal pull-up at SEL pin). Further, the
SPI-specific pins (like: SS, MISO) do not need to be connected at all for I²C operation.
To also provide interface accessibility in Sleep State (all IC features inactive except for the digital interface logic),
the interface circuitry is directly supplied by VDD.
*. Functional I2C interface properties correspond to the NXP I²C bus specification Rev. 0.3 (June 2009).
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
18 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
3
Functional Description
3.1.
Power Up
Specifications for this section are given in sections 1.2 and 1.3. On power-up, the ZSSC3026 communication
interface is able to receive the first command after a time tSTA1 from when the VDD supply is within operating
specifications. The ZSSC3026 can begin the first measurement after a time of tSTA2.from when the VDD supply is
operational.
The wake up time from Sleep State to Active State after receiving the activating command is defined as tWUP1 and
tWUP2. In Command Mode, subsequent commands can be sent after tWUP1. The first measurement starts after tWUP2
if measurement request was sent.
3.2.
Measurements
Available measurement procedures are
•
•
•
•
AZBM: auto-zero bridge measurement
BM: bridge measurement
AZTM: auto-zero temperature measurement
TM: temperature measurement
AZBM: The configuration for bridge measurements is loaded. The Multiplexer connects the Amplifier input to the
AGND analog ground reference. An analog-to-digital conversion is performed so that the inherent system offset
for the bridge configuration is converted by the ADC to a 16-bit digital word.
BM: The configuration for bridge measurements is loaded. The Multiplexer connects the Amplifier input to the
bridge pins: INP and INN. An analog-to-digital conversion is performed. The result is a 16-bit digital word.
AZTM: The configuration for temperature measurements is loaded. The Multiplexer connects the Amplifier input
to AGND. An analog-to-digital conversion is performed so that the inherent system offset for the temperature
configuration is converted by the ADC to a 16-bit digital word.
TM: The configuration for temperature measurements is loaded. The Multiplexer connects the Amplifier input to
the internal temperature sensor. An analog-to-digital conversion is performed. The result is a 16-bit digital word.
The typical application’s measurement cycle is a complete SSC-measurement (using the command: ACHEX) with
AZBM, BM, AZTM, TM followed by a signal correction calculation.
3.3.
Operational Modes
Figure 3.1 illustrates the ZSSC3026 power-up sequence and subsequent operation depending on the selected
2
interface communication mode (I C or SPI). With either interface, after the voltage regulators are switched on, the
ZSSC3026’s low voltage section (LV) is active while the related interface configuration information is read from
memory. Then the LV section is switched off, the ZSSC3026 goes into Sleep State, and the interface is ready to
receive commands. Since the interface is always powered by VDD, it is referred to as the high voltage section
(HV).
Figure 3.2 shows the ZSSC3026 operation in Normal Mode and Command Mode including when the LV and HV
sections are active as indicated by the color legend. The Normal Mode automatically returns to Sleep State after
executing the requested measurements. In Command Mode, the ZSSC3026 remains active if a dedicated
command (Start_NOM) was sent, which is helpful during calibration. Command Mode can only be entered if
Start_CM is the very first command after POR.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
19 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
Data/Status
from LV
Data/Status
from LV
Figure 3.1 Operational Flow Chart: Power up.
20 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Figure 3.2 Operational Flow Chart: Command Mode and Normal Mode.
3.4.
3.4.1.
Command Interpretation
SPI/I2C Commands
The user-accessible section of memory includes addresses 00HEX through 17HEX in the OTP memory that is
designated by the user memory page pointer. Because each of the four OTP memory pages cannot be rewritten
or erased, the memory page pointer must be incremented to the next OTP memory page in order to write to
memory again (see Table 3.1 for the command). After all four user-accessible OTP memory pages have been
used, further write operations are not possible and the “Memory Full” bit is returned as set in the status byte after
write operations (see section 3.5.1).
2
The SPI/I C commands supported by the ZSSC3026 are listed in Table 3.1. The command to read an address in
the user memory is the same as its address. The command to read the 16-bit memory status of the data at an
address in user memory is the address plus 20HEX. The command to write to an address in user memory is the
address plus 40HEX.
Data Sheet
May 15, 2012
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
21 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
There is a ZMDI-reserved section of memory, which can be read but not over-written by the user.
Table 3.1
SPI/I2C Commands.
Command
(Byte)
Description
Normal
Mode
Command
Mode
Read data in user memory address matching
command (addresses 00HEX to 17HEX; might
not be using all addresses).
yes
yes
16-bit user memory
status
Read memory status for address specified by
command minus 20HEX (addresses 00HEX to
17HEX respectively; see section 3.6.2 for a
description of the memory status).
yes
yes
40HEX to 57HEX +
data (0000HEX to
FFFFHEX)
—
Write data to user memory at address
specified by command minus 40HEX
(addresses 00HEX to 17HEX respectively; might
not be using all addresses).
no
yes
70HEX to 7EHEX
16-bit ZMDI-reserved
memory data
Read data in ZMDI-reserved memory at
address specified by command minus 70HEX
nd
(2 set of addresses 00HEX to 0EHEX
respectively).
no
yes
16-bit ZMDI-reserved
memory status
Read memory status bytes for ZMDIreserved memory data at address specified
nd
by command minus 80HEX (2 set of
addresses 00HEX to 0EHEX respectively; see
section 3.6.2 for a description of the memory
status bytes).
no
yes
00HEX to 17HEX
20HEX to 37HEX
80HEX to 8EHEX
*
Returns
16-bit user data
5EHEX
—
Increment user memory page pointer.
no
yes
A0HEX to A7HEX +
XXXXHEX
16-bit wide raw data
Get_Raw This command can be used to
perform a measurement and write the raw
ADC data into the output register. The LSB of
the command determines how the AFE
configuration register is loaded for the
Get_Raw measurement (see Table 3.2).
yes
yes
no
yes
(see Table 3.2)
A8HEX
—
Start_NOM Exit Command
transition to Normal Mode.
A9HEX
—
Start_CM Exit Normal Mode and transition
to Command Mode.
yes
no
AAHEX
—
Write_ChecksumC If not yet written, the
checksum for the valid user MTP page is
calculated and written to MTP. The VPP
voltage must be applied before, during, and
after this command.
no
yes
16-bit fully corrected
bridge measurement data
+ 16-bit corrected internal
temperature
Measure Triggers full measurement cycle
(AZBM, BM, AZTM, TM, as described in section 3.2) and calculation and storage of data
in interface (configurations from MTP).
yes
yes
Status + last data
NOP
yes
yes
ACHEX
FXHEX
Mode
and
Only valid for SPI (see section 3.5.1).
* Every response starts with a status byte followed by the data word as described in section 3.5.1.
Data Sheet
May 15, 2012
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
22 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Table 3.2
Get_Raw Commands.
Command
Measurement
AFE Configuration Register
A0HEX + 0000HEX
BM – Bridge Measurement
BM_Config
A1HEX + ssssHEX
BM – Bridge Measurement
ssss is the user’s configuration setting for the
measurement provided via the interface. The
format and purpose of configuration bits must
be equal to the definitions for BM_Config.
A2HEX + 0000HEX
BM-AZBM –
1)
Measurement
Auto-Zero
corrected
Bridge
A3HEX + ssssHEX
BM-AZBM –
2)
Measurement
Auto-Zero
corrected
Bridge
A4HEX + 0000HEX
TM – Temperature Measurement
ZMDI-defined register
A5HEX + ssssHEX
TM – Temperature Measurement
ssss is the user’s configuration setting for the
measurement provided via the interface. The
format and purpose of configuration bits must
be equal to the definitions for BM_Config
being valid for temp. measurement in this
case (bits [15:13] will be ignored).
A6HEX + 0000HEX
TM-AZTM – Auto-Zero corrected Temperature
1)
Measurement
A7HEX + ssssHEX
TM-AZTM – Auto-Zero corrected Temperature
2)
Measurement
BM_Config
ssss is the user’s configuration setting for the
measurement provided via the interface. The
format and purpose of configuration bits must
be equal to the definitions for BM_Config.
ZMDI-defined register
ssss is the user’s configuration setting for the
measurement provided via the interface. The
format and purpose of configuration bits must
be equal to the definitions for BM_Config
being valid for temp. measurement in this
case (bits [15:13] will be ignored).
1)
recommended for raw data collection during calibration coefficient determination using pre-programmed (in MTP) measurement setups
2)
recommended for raw data collection during calibration coefficient determination using un-programmed (not in MTP), external measurement
setups, e.g. for evaluation purposes
3.5.
Communication Interface
3.5.1.
Common Functionality
Commands are handled by the command interpreter in the LV section. Commands which need additional data are
not treated differently than other commands because the HV interface is able to buffer the command and all data
that belongs to the command, and the command interpreter is activated as soon as a command byte is received.
Every response starts with a status byte followed by the data word. The data word depends on the previous
2
command. It is possible to read the same data more than once if the read request is repeated (I C) or a NOP
command is sent (SPI). If the next command is not a read request (I²C) or a NOP (SPI), it invalidates any
previous data.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
23 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
The status byte contains the following bits (see Table 3.3, Table 3.4, and Table 3.5 for sequence):
• Power indication (bit 6): 1 if the device is powered (VDDB on); 0 if not powered. This is needed for SPI Mode
where the master reads all zeros if the device is not powered or in power-on reset (POR).
• Busy indication (bit 5): 1 if the device is busy, which indicates that the data for the last command is not
available yet. No new commands are processed if the device is busy.
• Actual ZSSC3026 mode (bits 4:3): 00 = Normal Mode; 01 = Command Mode; 1X = ZMDI-reserved.
• Memory integrity/error flag (bit 2): 0 if integrity test passed, 1 if test failed. This bit indicates whether the
checksum-based integrity check passed or failed. Correctable errors are not reported but can be queried
with the memory status commands (see section 3.6.2). The memory error status bit is calculated only
during the power-up sequence, so a newly written CRC will only be used for memory verification and status
update after a subsequent IC power-on reset (POR).
• Data transfer/correction (bit 1): If the last command was a memory write, this bit is 0 if the last memory
write was successful (memory not full yet), otherwise it is 1 (e.g. page increase but being already on last
MTP page). If the last command was a memory read, this bit is 1 if the data was corrected.
Table 3.3
General Status Byte.
Bit
7
6
5
Meaning
0
Powered?
Busy?
Table 3.4
7
6
5
Meaning
0
Powered?
Busy?
Mode
2
1
0
Memory error?
Data transfer
Special
4
3
2
1
0
Mode
Memory error?
Data corrected?
ALU saturation?
Status Byte for Write Operations.
Bit
7
6
5
Meaning
0
Powered?
Busy?
Table 3.6
3
Status Byte for Read Operations.
Bit
Table 3.5
4
4
3
Mode
2
Memory error?
1
Memory full? MTP write reject?
0
Don’t care
Mode Status.
Status[4:3]
Mode
00
Normal Mode
01
Command Mode
10
ZMDI-Reserved
11
Command Mode and Reserved
The memory error status bit is only calculated during the power-up sequence, so a newly written CRC will only be
used for memory verification after a subsequent power-on reset (POR).
Further status information are provided by the EOC pin. The EOC pin is set high when a measurement and
calculation have been completed.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
24 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
3.5.2.
SPI
The SPI Mode is available when the SEL pin = 0. The polarity (controlled by CPOL bit) and the phase (controlled
by CPHA bit) of the SPI clock (CKP_CKE) and the polarity of the SS signal (SS_polarity) are programmable as
described in Table 3.8. CKP_CKE is two bits: CPHA, which selects which edge of SCLK latches data, and CPOL
which indicates whether SCLK is high or low when it is idle. The different combinations of polarity and phase are
illustrated in the figures below.
Figure 3.3 SPI configuration CPHA=0.
CPHA=0
SCLK (CPOL=0)
SCLK (CPOL=1)
MOSI
MSB
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
LSB
MISO
MSB
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
LSB
/SS
SAMPLE
Figure 3.4 SPI Configuration CPHA=1.
CPHA=1
SCLK (CPOL=0)
SCLK (CPOL=1)
MOSI
MSB
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
LSB
MISO
MSB
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
LSB
/SS
SAMPLE
In SPI mode, each command except NOP is started as shown in Figure 3.5. After the execution of a command
(busy = 0), the expected data can be read as illustrated in Figure 3.6 or if no data are returned by the command,
the next command can be send. The status can be read at any time with the NOP command (see Figure 3.7
Data Sheet
May 15, 2012
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
25 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Figure 3.5 SPI Command Request.
Command Request
MOSI
Command
other than
NOP
CmdDat
<15:8>
CmdDat
<7:0>
MISO
Status
Data
Data
Note: A command request always consists of 3 bytes. If the command is shorter, then it must be completed with 0s.
The data on MISO depend on the preceding command.
Figure 3.6 SPI Read Status.
Read Status
MOSI
Command
= NOP
MISO
Status
Figure 3.7 SPI Read Data.
Read Data
(a) Example: after the completion of a Memory Read command
MOSI
Command
= NOP
00HEX
00HEX
MISO
Status
MemDat
<15:8>
MemDat
<7:0>
(b) Example: after the completion of a Full Measurement command (ACHEX)
Data Sheet
May 15, 2012
MOSI
Command
= NOP
00HEX
00HEX
00HEX
00HEX
MISO
Status
BridgeDat
<15:8>
BridgeDat
<7:0>
TempDat
<15:8>
TempDat
<7:0>
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
26 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
3.5.3.
2
IC
2
2
I C Mode is selected by SEL = 1. In I C Mode, each command is started as shown in figure x.1. Only the number
of bytes that is needed for the command has to be sent. An exception is the HS-mode where always 3 Bytes must
be sent like in SPI mode. After the execution of a command (busy = 0) the expected data can be read as
illustrated in figure 3.10. or if no data are returned by the command the next command can be sent. The status
can be read at any time as described in figure 3.9.
2
I C Command Request.
Figure 3.8
Command Request (I2C Write)
S SlaveAddr
0 A Command
from master to slave
S
START condition
from slave to master
P
STOP condition
A
acknowledge
N
not acknowledge
A P
write
S SlaveAddr
0 A Command
A
CmdDat
<15:8>
A
CmdDat
<7:0>
A P
write
Figure 3.9
I2C Read Status.
Read Status (I2C Read)
S SlaveAddr
1 A
Status
N P
read
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
27 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
2
Figure 3.10 I C Read Data.
Read Data (I2C Read)
(a) Example: after the completion of a Memory Read command
S SlaveAddr
1 A
Status
A
MemDat
<15:8>
A
MemDat
<7:0>
N P
read
(b) Example: after the completion of a Full Measurement command (ACHEX)
S SlaveAddr
1 A
Status
A
BridgeDat
<15:8>
A
BridgeDat
<7:0>
A
TempDat
<15:8>
A
TempDat
<7:0>
N P
read
All mandatory I²C-bus protocol features are implemented. Optional features like clock stretching, 10-bit slave
address, etc., are not supported by the ZSSC3026’s interface.
In I²C-High Speed Mode, a command consists of a fixed length of three bytes.
3.6.
Memory
In the ZSSC3026, the memory is organized page-wise and can be programmed multiple (4) times (MTP). Each
register can only be programmed once per page. The valid page is determined by the page counter which can be
incremented with the command 5EHEX – this leads to a “reset” of all registers and a re-programming is necessary.
Increasing the customer page counter will disable all old register contents of the former page. It is possible to
(re-)program 4 pages totally. Resetting the page counter is not possible. The page counter starts with 0 and can
th
become 3 at maximum. If the 4 memory page has been used, no further changes in the memory are possible –
careful writing and page incrementing is strongly recommended. There are two MTP page types:
• Customer Page: accessible by means of regular write operations (40HEX to 57HEX). It contains: IC-ID,
interface setup data, measurement setup information, calibration coefficients, etc.
• ZMDI Page:
3.6.1.
only accessible for write operations by ZMDI. The ZMDI page contains specific trim
information and is programmed during manufacturing test by ZMDI.
Programming Memory
Programming memory requires a specific supply voltage level (>2.9V) at VDD pin (see section 1.3 for
specifications). The MTP programming voltage itself is generated by means of an implemented charge pump; no
additional, external voltage, other than VDD needed. The program timing is shown in Figure 3.11. Supplying the
ZSSC3026 with VDD>2.9V during memory programming is required. After the memory is programmed, it must be
read again to verify the validity of the memory content.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
28 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Figure 3.11 Memory Program Operation.
3.6.2.
Memory Status Commands
The 16-bit memory status answer for the commands: 20HEX to 37HEX and 80HEX to 8EHEX contains the following
information:
• One bit indicating if the data read was corrected.
• Two bits indicating the current page in use.
Table 3.7
Memory Status Word.
Bit
15 (MSB)
14
Description
Data was corrected (0: no, 1: yes)
Current page
13
12:0
Data Sheet
May 15, 2012
Undefined – do not use
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
29 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
3.6.3.
Memory Contents
Table 3.8
MTP
Address
MTP Memory Content Assignments.
Word / Bit
Range
Default
Setting
Description
Notes / Explanations
00HEX
15:0
0000HEX
Cust_ID0
Customer ID byte 0 (combines with memory word
01HEX to form customer ID)
01HEX
15:0
0000HEX
Cust_ID1
Customer ID byte 1 (combines with memory word
00HEX to form customer ID)
6:0
000 0000BIN
Slave_Addr
I²C slave address; valid range: 00HEX to 7FHEX
(default: 00HEX), Remark: address codes 04HEX to
2
07HEX reserved for entering I C High Speed Mode
8:7
00BIN
-
Reserved
Interface Configuration
Determines the polarity of the Slave Select pin (SS)
for SPI operation:
9
0BIN
SS_polarity
•
•
Clock polarity and clock-edge select—determines
polarity and phase of SPI interface clock with the
following modes:
02HEX
•
•
11:10
00BIN
CKP_CKE
•
•
15:12
Data Sheet
May 15, 2012
0 Slave Select is active low (SPI &
ZSSC3026 are active if SS==0)
1 Slave Select is active high (SPI &
ZSSC3026 are active if SS==1)
-
00 SCLK is low in idle state, data latch
with rising edge and data output with falling
edge
01 SCLK is low in idle state, data latch
with falling edge and data output with rising
edge
10 SCLK is high in idle state, data latch
with falling edge and data output with rising
edge
11 SCLK is high in idle state, data latch
with rising edge and data output with falling
edge
Not assigned
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
30 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
MTP
Address
Word / Bit
Range
Default
Setting
Description
Notes / Explanations
Signal Conditioning Parameters
03HEX
0
0BIN
Offset_B[16]
Bridge offset, bit[16]—functions as the MSB and
combines with Offset_B[15:0] in 05HEX to form the
17-bit coefficient’s absolute value
1
0BIN
Offset_B_sign
Sign for sensor bridge offset (Offset_B):
0 => a positive value or
1 => a negative value
2
0BIN
Gain_B[16]
Bridge gain, bit[16] —functions as the MSB and
combines with Gain_B[15:0] in 06HEX to form the 17bit coefficient’s absolute value
3
0BIN
Gain_B_sign
Sign of the sensor bridge gain (Gain_B):
0 => a positive value or
1 => a negative value
Tcg[16]
1 -order temperature coefficient of the bridge gain,
bit[16] —functions as the MSB and combines with
Tcg[15:0] in 07HEX to form 17-bit coefficient’s
absolute value
Tcg_sign
Sign off 1 -order temperature coefficient (Tcg):
0 => a positive value or
1 => a negative value
Tco[16]
1 -order temperature coefficient of the bridge offset,
bit[16] —functions as the MSB and combines with
Tco[15:0] in 08HEX to form 17bit coefficient’s absolute
value
Tco_sign
Sign of 1 -order temperature coefficient (Tco):
0 => a positive value or
1 => a negative value
SOT_tco[16]
2 -order temperature coefficient of the bridge offset,
bit[16] —functions as the MSB and combines with
SOT_tco[15:0] in 09HEX to form 17-bit coefficient’s
absolute value
SOT_tco_sign
Separate setting if 2 -order temperature coefficient
(SOT_tco) is:
0 => a positive value or
1 => a negative value
SOT_tcg[16]
2 -order temperature coefficient of the bridge gain,
bit[16] —functions as the MSB and combines with
SOT_tcg[15:0] in 0AHEX to form 17-bit coefficient’s
absolute value
SOT_tcg_sign
Separate setting (sign) if 2 -order temperature
coefficient (SOT_tcg) is:
0 => a positive value or
1 => a negative value
st
4
0BIN
st
5
0BIN
st
6
0BIN
st
7
0BIN
nd
8
0BIN
nd
9
0BIN
nd
10
0BIN
nd
11
Data Sheet
May 15, 2012
0BIN
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
31 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
MTP
Address
Word / Bit
Range
Default
Setting
Description
Notes / Explanations
nd
12
0BIN
SOT_bridge[16]
2 -order coefficient of the bridge signal, bit[16] —
functions as the MSB and combines with
SOT_bridge[15:0] in 0BHEX to form 17-bit coefficient’s
absolute value
SOT_bridge_sign
Separate setting if 2 -order bridge coefficient
(SOT_bridge) is
0 => a positive value or
1 => a negative value
nd
13
0BIN
Type of second order curve correction for the bridge
sensor signal.
14
0BIN
SOT_curve
15
0BIN
TSETL_sign
Separate setting T_SETL is
0 => a positive value or
1 => a negative value
0 parabolic curve
1 s-shaped curve
0
0BIN
Gain_T[16]
Temperature gain of temperature sensor, bit[16]
functions as the MSB and combines with
Gain_T[15:0] in 0DHEX to form 17-bit coefficient’s
absolute value
1
0BIN
Gain_T_sign
Separate setting if the temperature gain (Gain_T) is:
0 => a positive value or
1 => a negative value
SOT_T[16]
2 -order temperature coefficient of temp. sensor,
bit[16] functions as the MSB and combines with
SOT_T[15:0] in 0EHEX to form 17-bit coefficient’s
absolute value
nd
2
0BIN
nd
3
0BIN
SOT_T_sign
Separate setting if 2 -order temperature coefficient
(SOT_T) is
0 => a positive value or
1 => a negative value
4
0BIN
Offset_T[16]
Temperature offset of temp. sensor, bit[16] functions
as the MSB and combines with Offset_T[15:0] in
0CHEX to form 17-bit coefficient’s absolute value
04HEX
Data Sheet
May 15, 2012
5
0BIN
Offset_T_sign
Separate setting if the temperature offset (Offset_T)
is
0 => a positive value or
1 => a negative value
15:6
0 0000 000
0BIN
-
Not assigned
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
32 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
MTP
Address
Word / Bit
Range
Default
Setting
Description
Notes / Explanations
Bits [15:0] of the bridge offset correction coefficient,
which is an 18-bit wide absolute value (the
respective MSBs Offset_B[16] and sign,
Offset_B_sign, are under bits[1:0] in 03HEX)
05HEX
15:0
06HEX
15:0
07HEX
15:0
08HEX
15:0
0000HEX
(7000HEX)
Offset_B[15:0]
[-1/16 to 15/16] = 7000HEX (default for volume)
[-2/16 to 14/16] = 6000HEX
[-3/16 to 13/16] = 5000HEX
[-4/16 to 12/16] = 4000HEX
[-5/16 to 11/16] = 3000HEX
[-6/16 to 10/16] = 2000HEX
[-7/16 to 9/16] = 1000HEX
[-8/16 to 8/16] = 0000HEX (default for prototypes)
Gain_B[15:0]
Bits[15:0] of 17-bit wide absolute value of the bridge
gain coefficient (default for prototypes: 0000HEX;
default for volume production: 8000HEX—the
respective MSBs, Gain_B[16] and sign,
Gain_B_sign, are under bits[3:2] in 03HEX)
0000HEX
Tcg[15:0]
Coefficient for temperature correction of the bridge
gain term – the respective MSBs, Tcg[16] and sign,
Tcg_sign, are under (bits[5:4] in 03HEX)
0000HEX
Tco[15:0]
Coefficient for temperature correction of the bridge
offset term – the respective MSBs, Tco[16] and sign,
Tco_sign, are under (bits[7:6] in 03HEX)
0000HEX
(8000HEX)
nd
09HEX
15:0
0000HEX
SOT_tco[15:0]
2 order term applied to Tco – the respective MSBs,
SOT_tco[16] and sign, SOT_tco_sign, are under
(bits[9:8] in 03HEX)
0AHEX
15:0
0000HEX
SOT_tcg[15:0]
2 order term applied to Tcg. – the respective
MSBs, SOT_tcg[16] and sign, SOT_tcg_sign, are
under (bits[11:10] in 03HEX)
SOT_bridge[15:0]
2 order term applied to the sensor bridge readout –
the respective MSBs, SOT_bridge[16] and sign,
SOT_bridge_sign are under (bits[13:12] in 03HEX)
nd
nd
0BHEX
15:0
0000HEX
Bits [15:0] of the temperature offset correction
coefficient (the respective MSBs, Offset_T[16] and
sign, Offset_T_sign, are under (bits[5:4] in 04HEX)
0CHEX
0DHEX
Data Sheet
May 15, 2012
15:0
15:0
0000HEX
(7000HEX)
0000HEX
(8000HEX)
Offset_T[15:0]
Gain_T[15:0]
[-1/16 to 15/16] = 7000HEX (default for volume)
[-2/16 to 14/16] = 6000HEX
[-3/16 to 13/16] = 5000HEX
[-4/16 to 12/16] = 4000HEX
[-5/16 to 11/16] = 3000HEX
[-6/16 to 10/16] = 2000HEX
[-7/16 to 9/16] = 1000HEX
[-8/16 to 8/16] = 0000HEX (default for prototypes)
Bits [15:0] of the absolute value of the temperature
gain coefficient (default for prototypes: 0000HEX;
default for volume production: 8000HEX — the
respective MSBs, Gain_T[16] and sign,
Gain_T_sign, are under bits[1:0] in 04HEX)
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
33 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
MTP
Address
Word / Bit
Range
Default
Setting
Description
Notes / Explanations
nd
0EHEX
15:0
0000HEX
SOT_T[15:0]
2 order term applied to the temperature reading –
the respective MSBs, SOT_T[16] and sign,
SOT_T_sign, are under (bits[3:2] in 04HEX)
0FHEX
15:0
0000HEX
T_SETL
Stores raw temperature reading at the temperature
at which low calibration points were taken
Measurement Configuration Register (BM_config)
st
Gain setting for the 1 PREÀMP stage with
Gain_stage1:
10HEX
1:0
00BIN
Gain_stage1
•
•
•
•
00 12
01 20
10 30
11 40
Gain setting for the 2
Gain_stage2:
•
•
4:2
000BIN
Gain_stage2
•
•
•
•
•
•
nd
PREAMP stage with
000 1.1
001 1.2
010 1.3
011 1.4
100 1.5
101 1.6
110 1.7
111 1.8
Set up the polarity of the sensor bridge’s gain
(inverting of the chopper) with
5
0BIN
Gain_polarity
•
•
0 positive (no polarity change)
1 negative (180° polarity change )
Absolute number of bits for the MSB conversion in
the ADC with Msb:
7:6
00BIN
(11BIN)
Msb
•
•
•
•
00 10-bit
01 12-bit
10 14-bit
11 16-bit
Absolute number of bits for the LSB conversion in
the ADC with Lsb:
9:8
00BIN
Lsb
•
•
•
•
Data Sheet
May 15, 2012
00 0-bit (single stage CB_ADC)
01 2-bit
10 4-bit
11 6-bit
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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the prior written consent of the copyright owner. The information furnished in this publication is subject to changes without notice.
34 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
MTP
Address
Word / Bit
Range
Default
Setting
Description
Notes / Explanations
ADC offset and resulting A2D input range [Vref] with
A2D_Offset:
•
•
12:10
000BIN
A2D_Offset
•
•
•
•
•
•
000 1/16 results in range [-1/16, 15/16]
001 2/16 results in range [-2/16, 14/16
010 3/16 results in range [-3/16, 13/16]
011 4/16 results in range [-4/16, 12/16]
100 5/16 results in range [-5/16, 11/16]
101 6/16 results in range [-6/16, 10/16]
110 7/16 results in range [-7/16, 9/16]
111 8/16 results in range [-8/16, 8/16]
Selection between fixed ADC segmentations for
temperature measurements:
•
14:13
00BIN
Temp_ADC
•
•
•
15
0BIN
-
00 setup according to ZMDI-reserved
memory (recommended setup for best
performance and speed trade-off)
01 MSB=16, LSB=0 (16-bit)
10 MSB=10, LSB=6 (16-bit)
11 MSB=12, LSB=4 (16-bit)
Reserved
11HEX
Not assigned
12HEX
Not assigned
13HEX
Not assigned
14HEX
Not assigned
15HEX
Not assigned
16HEX
Not assigned
17HEX
Generated (checksum) for user page through a
linear feedback shift register (LFSR); signature is
checked with power-up to ensure memory content
integrity
15:0
-
ChecksumC
The memory integrity checksum is generated through a linear feedback shift register with the polynomial:
16
15
2
g(x) = x + x + x + 1
with the initialization value: FFFFHEX.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
35 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
3.7.
Calibration Sequence
Calibration essentially involves collecting raw signal and temperature data from the sensor-IC system for different
known bridge values and temperatures. This raw data can then be processed by the calibration master (assumed
to be a PC), and the calculated calibration coefficients can then be written to MTP memory. Below is a brief
overview of the steps involved in calibrating the ZSSC3026.
There are three main steps to calibration:
1. Assigning a unique identification to the ZSSC3026. This identification is written to shadow RAM and later
programmed in MTP memory. This unique identification can be stored in the two 16-bit registers
dedicated to customer ID. It can be used as an index into a 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 bridge measurand conditions and temperature to which the bridge was exposed.
2. Data collection. Data collection involves getting uncorrected or raw data from the bridge at different
known measurand values and temperatures. Then this data is stored on the calibration PC using the
unique identification of the device as the index to the database.
3. Coefficient calculation and storage in MTP memory. After enough data points have been collected to
calculate all the desired coefficients, the coefficients can be calculated by the calibrating PC and written
to the shadow RAM. After that, MTP memory is programmed with the contents of the shadow RAM.
4. Result. The sensor signal and the characteristic temperature effect on output will be linearized according
to the setup-dependent maximum output range.
It is essential to perform the calibration with a fixed programming setup during the data collection phase. In order
to prevent any accidental misprocessing, it is further recommended to keep the MTP memory setup stable during
the whole calibration process as well as in the subsequent operation. A ZSSC3026 calibration only fits the single
setup used during its calibration. Changes of functional parameters after a successful calibration can decrease
the precision and accuracy performance of the ZSSC3026 as well as of the whole application.
3.7.1.
Calibration Step 1 – Assigning Unique Identification
Assign a unique identification number to the ZSSC3026 by using the memory write command (40HEX + data and
41HEX + data; see Table 3.1 and Table 3.8) to write the identification number to Cust_ID0 at memory address
00HEX and Cust_ID1 at address 01HEX as described in section 3.6.1. These two 16-bit registers allow for more than
4 trillion unique devices.
3.7.2.
Calibration Step 2 – Data Collection
The number of unique points (measurand and/or temperature) at which calibration must be performed generally
depends on the requirements of the application and the behavior of the resistive bridge in use. The minimum
number of points required is equal to the number of bridge coefficients to be corrected with a minimum of three
different temperatures at three different bridge values. For a full calibration resulting in values for all 7 possible
bridge coefficients and 3 possible temperature coefficients, a minimum of 7 pairs of bridge with temperature
measurements must be collected..
Within this minimum 3x3 measurements field, data must be collected for the specific value pairs (at known
conditions) and then processed to calculate the coefficients. In order to obtain the potentially best and most robust
coefficients, it is recommended that measurement pairs (temperature vs. pressure) be collected at the outer
corners of the intended operation range or at least at points which are located far from each other. It is also
essential to provide highly precise reference values as nominal, expected values. The measurement precision of
the external calibration-measurement equipment should be ten times more accurate than the expected
ZSSC3026 output precision after calibration in order to avoid precision losses caused by the nominal reference
values (e.g., pressure signal and temperature deviations).
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
36 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Note: An appropriate selection of measurement pairs can significantly improve the overall system performance.
The determination of the measurand-related coefficients will use all of the measurement pairs. For the
temperature-related correction coefficients, 3 (at three different temperatures) of the e.g. 7 measurement pairs will
be used.
Note: There is an inherent redundancy in the 7 bridge-related and 3 temperature-related coefficients. Since the
temperature is a necessary output (which also needs correction), the temperature-related information is
mathematically separated, which supports faster and more efficient DSP calculations during the normal usage of
the sensor-IC system.
The recommended approach for data collection is to make use of the raw-measurement commands:
•
for bridge sensor values:
•
3.7.3.
o
A2HEX + 0000HEX:
single bridge measurement whereas the configuration register will be loaded
from the BM_Config register (10HEX in MTP); preprogramming the measurement
setup in the MTP is required.
o
A3HEX + ssssHEX:
single bridge measurement whereas the BM_Config configuration register
(Gain, ADC, Offset, etc.) will be loaded as ssssHEX and must be provided
externally via the interface.
for temperature values:
o
A6HEX + 0000HEX:
single temperature measurement whereas the configuration register will be
loaded from an internal temperature configuration register (preprogrammed by
ZMDI in MTP); preprogramming of the respective configuration is done by ZMDI
prior to IC delivery. This is the recommended approach for temperature data
collection.
o
A7HEX + ssssHEX:
single temperature measurement whereas the configuration register
(Gain, ADC, Offset, etc.) will be loaded as ssssHEX and must be provided
externally via the interface. The data composition of the temperature
configuration register is similar to the BM_config (address 10HEX) register
for the bridge sensor.
Calibration Step 3 – Coefficient Calculations
The math to perform the coefficient calculation is complicated and will not be discussed in detail. There is a brief
overview in the next section. ZMDI will provide software (DLLs) to perform the coefficient calculation (external to
the sensor-IC system) based on auto-zero corrected values. After the coefficients are calculated, the final step is
to write them to the MTP memory of the ZSSC3026.
3.8.
3.8.1.
The Calibration Math
Bridge Signal Compensation
The saturation check in the ZSSC3026 is enhanced compared with older SSCs from ZMDI. Even saturation
effects of the internal calculation steps are detected, even though the final correction output will still be
determined. It is possible to get seemingly useful signal conditioning results which have seen an intermediate
saturation during the calculations – these cases are detectable by observing the status bit[0] for each
measurement result. Details about the saturation limits and the valid ranges for values are provided in the
following equations.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
37 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
SOT_curve selects whether second-order equations compensate for sensor nonlinearity with a parabolic or
S-shaped curve. The parabolic compensation is recommended.
The correction formula for the differential signal reading is represented as a two-step process depending on the
SOT_curve setting.
Equations for the parabolic SOT_curve setting (SOT_curve = 0):
Simplified:
∆T = T _ Raw − TSETL
(5)
∆T  SOT_ tcg

⋅
⋅ ∆T + Tcg 
215  215

∆T  SOT _ tco

K 2 = Offset_ B + BR _ Raw + 15 ⋅ 
⋅ ∆T + Tco
15
2  2

Gain _ B K1
(delimited to positive number range)
Z BP =
⋅ 15 ⋅ K 2 + 215
215
2
Z BP  SOT_ bridge

(delimited to positive number range)
B = 15
⋅
⋅ Z BP + 215 
15
2 
2

K1 = 215 +
(6)
(7)
(8)
(9)
Complete:
∆T = [T _ Raw − TSETL ]−217
217 −1



∆T
K1 = 215 +  15
2



(10)
217 −1
 SOT _ tcg


⋅ 
⋅ ∆T 
+ Tcg 
15
 −217
 2
 −217
217 −1





∆T
K 2 = Offset_ B +  BR _ Raw +  15
2






217 −1



 −217




 −217
(11)
17
2 −1
2 −1
 SOT _ tco


⋅ 
⋅
∆
T
+ Tco
15

 −217
 2
 17
−2
17
217 −1



 −217
217 −1




 −217
217 −1





 −217
(13)
216 −1
2 −1

217 −1
 
Z BP  SOT_ bridge


15
B = 15 ⋅ 
⋅ Z BP 
+2  
 2 
17
215

 17 
−2

−2 
0

17
Data Sheet
May 15, 2012
(12)
217 −1
2 −1


217 −1 
Gain _ B  K1


15 

= 
⋅
⋅
K
+
2
 215 2  17
  215


 −2  17
−2
 
 0
17
Z BP
2 −1
17
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
(14)
38 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Equations for the S-shaped SOT_curve setting (SOT_curve = 1):
Simplified:
Gain _ B K1
Z BS =
⋅ 15 ⋅ K 2
215
2
B =
(15)
Z BS  SOT_ bridge

⋅
⋅ Z BS + 215  + 215
15 
15
2 
2

(delimited to positive number range)
(16)
Complete:
17
Z BS
217 −1
2 −1
 Gain _ B  K
 
1
=
⋅
⋅
K
15
 215 2  17 

 −2  17
 2
−2

 Z BS
B =  15

 2

(17)
2 −1




+ 215 


 −217

17
217 −1
 SOT_ bridge


15

⋅ 
⋅
+
Z
2
BS
 17
215
 −2

 17
−2
217 −1
216
(18)
0
Where
2
B
=
Corrected bridge reading output via I C or SPI; range [0HEX .. FFFFHEX];
BR_Raw
=
Raw bridge reading from ADC after AZ correction; range [-1FFFFHEX .. 1FFFFHEX];
Gain_B
=
Bridge gain term; range [-1FFFFHEX .. 1FFFFHEX];
Offset_B
=
Bridge offset term; range [-1FFFFHEX .. 1FFFFHEX];
Tcg
=
Temperature coefficient gain term; range [-1FFFFHEX .. 1FFFFHEX];
Tco
=
Temperature coefficient offset term; range [-1FFFFHEX .. 1FFFFHEX];
T_Raw
=
Raw temperature reading after AZ correction; range [-1FFFFHEX .. 1FFFFHEX];
TSETL
=
T_Raw reading at which low calibration was performed (e.g. 25°C);
range [-FFFFHEX .. FFFFHEX];
SOT_tcg
=
Second-order term for Tcg non-linearity; range [-1FFFFHEX .. 1FFFFHEX];
SOT_tco
=
Second-order term for Tco non-linearity; range [-1FFFFHEX .. 1FFFFHEX];
SOT_bridge =
Second-order term for bridge non-linearity; range [-1FFFFHEX .. 1FFFFHEX];
K
=
absolute value;
[K]ulll
=
bound/saturation number range from ll to ul, over/under-flow is reported as saturation in
status byte.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
39 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
3.8.2.
Temperature Signal Compensation
Temperature is measured internally. Temperature correction contains both linear gain and offset terms as well as
a second-order term to correct for any nonlinearities. For temperature, second-order compensation for
nonlinearity is always parabolic. Again, the correction formula is best represented as a two-step process as
follows:
Simplified:
Gain _ T
ZT =
⋅ (T _ Raw + Offset _ T ) + 215
215
Z  SOT_ T

T = 15T ⋅  15 ⋅ ZT + 215 
2  2

(delimited to positive number range)
(19)
(delimited to positive number range)
(20)
Complete:
217 −1
2 −1
 Gain _ T

217 −1 
Z T = 
⋅
[
T
_
Raw
+
Offset
_
T
]
+ 215 
17
−2 
15
 −217
 2
 0
17
216 −1
2 −1

217 −1
 
ZT  SOT_ T


15
T = 15 ⋅  15 ⋅ Z T 
+2  
 2  2
17

 17 
−2

−2 
0

17
(21)
(22)
Where
Gain_T
=
Gain coefficient for temperature; range [-1FFFFHEX .. 1FFFFHEX];
T_Raw
=
Raw temperature reading after AZ correction; range [-1FFFFHEX .. 1FFFFHEX];
Offset_T
=
Offset coefficient for temperature; range [-1FFFFHEX .. 1FFFFHEX];
SOT_T
=
Second-order term for temperature source non-linearity; range [-1FFFFHEX .. 1FFFFHEX]
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
40 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
4 Die Dimensions and Pin Assignments
2
The ZSSC3026 is available in die form (chip size with scribe line: 1.5mm - see Figure 4.1 for additional
dimensions.), as bumped die and in PQFN24 4x4 package.
In Figure 4.1, the shown outer dimensions are estimations for a die after sawing with remaining scribe-line silicon
of ca. 20um around the core die. Thus, the effective outer dimensions may differ slightly.
Figure 4.1 ZSSC3026 Pad Placement.
Table 4.1
Die Size & Geometry.
Parameter
MIN [um]
TYP [um]
Description / Remarks
X-dimension
900
925
Y-dimension
1560
1585
79.5
80
60
60
including seal ring and remaining “empty” silicon after
sawing; maximum dimensions may be larger for
engineering samples due to wider scribe lines
passivation window opening … effective area for bond
connection
valid only for two special pads: VDD2, EOC2 being
shorted with VDD and EOC, respectively
200
-
0
40
80
-
BondPad Size
(X & Y)
Minimum pitch for
application
relevant pads
Die size adder
beyond seal ring
Sawing lane
Data Sheet
May 15, 2012
Center-to-center distance; there are further pads,
which are only for ZMDI’s test purposes
potentially remaining silicon after die sawing
Die to die distance
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
41 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Table 4.2
Pin Assignments.
Name
Direction
Type
IN
Supply
IN
OUT
OUT
IN
IN
Supply
Analog
Analog
Analog
Analog
OUT
Digital
IN
IN
IN/Out
OUT
IN
-
Digital
Digital
Digital
Digital
Digital
-
VDD1
VDD2
VSS
VSSB
VDDB
INP
INN
EOC1
EOC2
SEL
SCLK/SCL
MOSI/SDA
MISO
SS
ZMDI-test
Data Sheet
May 15, 2012
Description
IC positive supply voltage for the IC, regular bond pad
IC positive supply voltage for the IC, special pad
(electrically connected to VDD1, also bondable)
Ground reference voltage signal
Negative bridge supply (bridge sensor ground)
Positive bridge supply
Positive bridge signal
Negative bridge signal
End of conversion, regular bond pad
End of conversion, special pad (electrically connected
to EOC1, also bondable)
I²C or SPI interface select
Clock input for I²C/SPI
Data input for SPI; data in/out for I²C
Data output for SPI
Slave select for SPI
do not connect to these pads
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
42 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
4.1.
Package (PQFN24) Properties
Figure 4.2 General PQFN24 Package Dimensions.
Table 4.3
Physical Package Dimensions’ Extrema.
Parameter / Dimension
Min [mm]
Max [mm]
A
0.80
0.90
A1
0.00
0.05
B
0.18
e
Data Sheet
May 15, 2012
0.30
0.5nom
HD
3.90
4.10
HE
3.90
4.10
L
0.35
0.45
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
43 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
Table 4.4
Pin No.
Pin Assignments PQFN24.
*)
Direction
Type
1
2
3
4
5
6
VSS
VSSB
ZMDI-test
INN
ZMDI-test
IN
OUT
IN
-
Supply
Supply
Analog
-
VDDB
OUT
Supply
7
8
9
10
11
12
13
14
15
16
17
18
INP
ZMDI-test
n.c.
n.c.
SCLK/SCL
MOSI/SDA
ZMDI-test
MISO
ZMDI-test
SS
ZMDI-test
IN
IN
IN / OUT
IN
IN
-
Analog
Digital
Digital
Digital
Digital
-
SEL
IN
Digital
EOC
OUT
Digital
n.c.
n.c.
n.c.
n.c.
IN
Supply
19
20
21
22
23
24
Name
VDD
Description
ground reference voltage signal
sensor bridge's ground
do not connect
negative bridge signal
do not connect
sensor bridge’s supply (driven from the IC),
Remark: Do not short with VDD!
positive bridge signal
do not connect
clock input for I²C / SPI
data input for SPI, data in/out-line for I²C
do not connect
data output for SPI
do not connect
slave select for SPI
do not connect
I²C or SPI Interface select
(internal pull up, 0…SPI, 1…I2C)
end of conversion … can be used as
“measurement completed” trigger
IC’s supply voltage
*) n.c. stands for not connected / no connection required / not bonded
5 Quality and Reliability
The ZSSC3026 is available as “consumer” and “industrial” qualified IC version. For the consumer version, all data
sheet parameters are guaranteed if not stated otherwise.
Additionally the MTP’s data retention capability (over ten years, cp. Table 1.4) is guaranteed for the industrial IC
version.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
44 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
6
Related Documents
Document
File Name
ZSSC3026 Feature Sheet
ZSSC3026_FeatureSheet_v*.pdf
ZSSC3026 Application Note: Application Circuits
ZSSC3026_ApplicationCircuit_v*.pdf
ZSSC30x6 Evaluation Kit Documentation
ZSSC30x6_EvaluationKit_v*.pdf
ZSSC30x6 Application Note: Calibration
ZSSC30x6_Calibration_v*.pdf
Visit ZMDI’s website www.zmdi.com or contact your nearest sales office for ordering information or the latest
version of these documents.
7
Glossary
Term
Description
A2D
Analog-to-digital
ACK
Acknowledge (interface’s protocol indicator for successful data/command transfer)
ADC
Analog-to-digital converter or conversion
AZ
Auto-Zero (unspecific)
AZS
Auto-Zero measurement for sensor bridge path
AZT
Auto-Zero Measurement for temperature path
CLK
Clock
DAC
Digital-to-analog conversion or converter
DF
Data Fetch (this is a command type)
DSP
Digital signal processor (digital configuration, calibration, calculation, communication unit)
FSO
Full scale output (value in percent relative to the ADC maximum output code; resolution dependent)
LSB
Least significant bit (“fine” portion of the converted signal)
LFSR
Linear Feedback Shift Register
MR
Measurement Request (this is a command type)
MSB
Most significant bit (“coarse” portion of the converted signal)
NACK
Not Acknowledge (interface’s protocol indicator for unsuccessful data/command transfer)
POR
Power-on reset
PreAmp
Preamplifier
SM
Signal measurement
SOT
Second-order term
TC
Temperature coefficient (of a resistor or the equivalent bridge resistance)
TM
Temperature measurement
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
45 of 46
ZSSC3026
Low Power 16 Bit Sensor Signal Conditioner IC
8
Document Revision History
Revision
Date
Description
1.00
January 06, 2012
First release official of Data Sheet
1.01
March 28, 2012
Change of ESD limit to 4kV, additional bump information, Reset conditions added
1.02
May 15, 2012
Included adjustments for temperature capabilities up to 110°C
Sales and Further Information
www.zmdi.com
[email protected]
Zentrum Mikroelektronik
Dresden AG (ZMD AG)
ZMD America, Inc.
ZMD AG, Japan Office
ZMD Far East, Ltd.
Grenzstrasse 28
01109 Dresden
Germany
8413 Excelsior Drive
Suite 200
Madison, WI 53717
USA
2nd Floor, Shinbashi Tokyu Bldg.
4-21-3, Shinbashi, Minato-ku
Tokyo, 105-0004
Japan
3F, No. 51, Sec. 2,
Keelung Road
11052 Taipei
Taiwan
Phone
Fax
Phone
Fax
Phone
Fax
Phone
Fax
+49 (0)351.8822.7.772
+49(0)351.8822.87.772
+01 (608) 829-1987
+01 (631) 549-2882
+81.3.6895.7410
+81.3.6895.7301
+886.2.2377.8189
+886.2.2377.8199
DISCLAIMER: This information applies to a product under development. Its characteristics and specifications are PRELIMINARY and subject to change without notice. Zentrum
Mikroelektronik Dresden AG (ZMD AG) assumes no obligation regarding future manufacture unless otherwise agreed to in writing. The information furnished hereby is believed to be true
and accurate. However, under no circumstances shall ZMD AG be liable to any customer, licensee, or any other third party for any special, indirect, incidental, or consequential damages of
any kind or nature whatsoever arising out of or in any way related to the furnishing, performance, or use of this technical data. ZMD AG hereby expressly disclaims any liability of ZMD AG
to any customer, licensee or any other third party, and any such customer, licensee and any other third party hereby waives any liability of ZMD AG for any damages in connection with or
arising out of the furnishing, performance or use of this technical data, whether based on contract, warranty, tort (including negligence), strict liability, or otherwise.
Data Sheet
May 15, 2012
© 2012 Zentrum Mikroelektronik Dresden AG — Rev. 1.02
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 subject to changes without notice.
46 of 46