Data Sheet Rev. 1.01 / August 2014 ZSSC3027 Low-Power, High-Resolution 16-Bit Sensor Signal Conditioner Mobile Sensing ICs Smart and Mobile ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Brief Description Benefits The ZSSC3027 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 ZSSC3027 can perform offset, st nd 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, non-volatile, multiple-time programmable (MTP) memory. Programming the ZSSC3027 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 ZSSC3027 provides accelerated signal processing in order to support high-speed control, safety, and real-time sensing applications. It complements ZMDI’s ZSSC30x6 products. Integrated 18-bit calibration math DSP Fully corrected signal at digital output One-pass calibration minimizes calibration costs No external trimming, filter, or buffering components required Highly integrated CMOS design Excellent for low-voltage and low-power battery applications Optimized for operation in calibrated resistive sensor modules Physical Characteristics Supply voltage range: 1.7 to 3.6V Operating mode current consumption: 930µA (typical) Sleep State current: 20nA (typical) Temperature resolution: <0.003K/LSB Operation temperatures: –40°C to +85°C Small die size Delivery options: die for wafer bonding Available Support ZSSC3026 Evaluation Kit can be used to evaluate ZSSC3027 capabilities Support Documentation ZSSC3027 Application Example Features Flexible, programmable analog front-end design; up to 16-bit scalable, charge-balancing twosegment 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 st nd gain as well as of 1 and 2 order temperature gain and offset drift Layout optimized for stacked-die bonding for high-density chip-on-board assembly Typical sensor elements can achieve accuracy of better than ±0.10% FSO** @ -40 to 85°C * I2C™ is a trademark of NXP. ** FSO = Full Scale Output. For more information, contact ZMDI via [email protected]. © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01— August 24, 2014. 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. ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC ZSSC3027 Block Diagram VDDB Vreg int VTP VTN Temperature Reference Sensor VDD AGND / CM Generator Bias Current Generator Power Ctr. Voltage Regulator VSS Sensor Bridge Multiplexer ZSSC3027 INP INN A PreAmplifier D 18-bit DSP Core (Calculations, Communication) 16 Bit VSSB SPI Applications Barometric altitude measurement for portable navigation or emergency call systems Altitude measurement for car navigation Inside hard disk pressure measurement Weather forecast Fan control Industrial, pneumatic, and liquid pressure High-resolution temperature measurements Power-ON Reset Clock Generator Ring Oscillator EOC System Control Unit MTP ROM I²CTM SCLK/SCL SS MOSI/SDA MISO SEL Ordering Information (See section 6 in the data sheet for additional options for delivery) Sales Code Description Delivery Package ZSSC3027AC1B Die—temperature range: –40°C to +85 °C Wafer (304µm) unsawn, tested ZSSC3027AC6B Die—temperature range: –40°C to +85 °C Wafer (725µm) unsawn, tested ZSSC3027AC7C Die—temperature range: –40°C to +85°C Wafer (200µm) unsawn, tested ZSSC3027AI1D Engineering samples, die—temperature range: –40°C to +85°C Dice in waffle pack (304µm) ZSSC3026-KIT Evaluation Kit for ZSSC3026, including boards, cable, software, and 1 ZSSC3026 PQFN24 sample (equivalent to ZSSC3027—kit is recommended for evaluation of the capabilities of the ZSSC3027) Sales and Further Information www.zmdi.com [email protected] Zentrum Mikroelektronik Dresden AG Global Headquarters Grenzstrasse 28 01109 Dresden, Germany ZMD America, Inc. 1525 McCarthy Blvd., #212 Milpitas, CA 95035-7453 USA Central Office: Phone +49.351.8822.306 Fax +49.351.8822.337 USA Phone 1.855.275.9634 Phone +1.408.883.6310 Fax +1.408.883.6358 European Technical Support Phone +49.351.8822.7.772 Fax +49.351.8822.87.772 DISCLAIMER: This information applies to a product under development. Its characteristics and specifications are 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. European Sales (Stuttgart) Phone +49.711.674517.55 Fax +49.711.674517.87955 Zentrum Mikroelektronik Dresden AG, Japan Office 2nd Floor, Shinbashi Tokyu Bldg. 4-21-3, Shinbashi, Minato-ku Tokyo, 105-0004 Japan ZMD FAR EAST, Ltd. 3F, No. 51, Sec. 2, Keelung Road 11052 Taipei Taiwan Phone +81.3.6895.7410 Fax +81.3.6895.7301 Phone +886.2.2377.8189 Fax +886.2.2377.8199 Zentrum Mikroelektronik Dresden AG, Korea Office U-space 1 Building 11th Floor, Unit JA-1102 670 Sampyeong-dong Bundang-gu, Seongnam-si Gyeonggi-do, 463-400 Korea Phone +82.31.950.7679 Fax +82.504.841.3026 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01—August 24, 2014. 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. ZSSC3027 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 (RSRR) vs. Frequency......................................................................... 10 Circuit Description ....................................................................................................................................... 11 2.1. Brief Description ................................................................................................................................... 11 2.2. Signal Flow and Block Diagram............................................................................................................ 11 2.3. Analog Front End .................................................................................................................................. 13 2.3.1. Amplifier ......................................................................................................................................... 13 2.3.2. Analog-to-Digital Converter ............................................................................................................ 14 2.3.3. Temperature Measurement ........................................................................................................... 18 2.3.4. Bridge Supply ................................................................................................................................. 18 2.4. 3 Digital Section ....................................................................................................................................... 18 2.4.1. Digital Signal Processor (DSP) Core ............................................................................................. 18 2.4.2. MTP Memory.................................................................................................................................. 18 2.4.3. Clock Generator ............................................................................................................................. 19 2.4.4. Power Supervision ......................................................................................................................... 19 2.4.5. Interface ......................................................................................................................................... 19 Functional Description ................................................................................................................................. 20 3.1. Power Up .............................................................................................................................................. 20 3.2. Measurements ...................................................................................................................................... 20 3.3. Operational Modes ............................................................................................................................... 20 3.4. Command Interpretation ....................................................................................................................... 22 3.4.1. 3.5. 2 SPI/I C™ Commands .................................................................................................................... 22 Communication Interface ...................................................................................................................... 25 3.5.1. Common Functionality ................................................................................................................... 25 3.5.2. SPI ................................................................................................................................................. 26 3.5.3. I C™ ............................................................................................................................................... 29 3.6. 2 Memory ................................................................................................................................................. 30 3.6.1. Programming Memory ................................................................................................................... 31 3.6.2. Memory Status Commands ........................................................................................................... 31 3.6.3. Memory Contents ........................................................................................................................... 32 Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 3.7. Calibration Sequence ........................................................................................................................... 38 3.7.1. Calibration Step 1 – Assigning Unique Identification ..................................................................... 38 3.7.2. Calibration Step 2 – Data Collection .............................................................................................. 38 3.7.3. Calibration Step 3 – Coefficient Calculations ................................................................................. 39 3.8. The Calibration Math ............................................................................................................................ 40 3.8.1. Bridge Signal Compensation ......................................................................................................... 40 3.8.2. Temperature Signal Compensation ............................................................................................... 43 4 Die Pad Assignments .................................................................................................................................. 44 5 Quality and Reliability .................................................................................................................................. 45 6 Ordering Sales Codes ................................................................................................................................. 45 7 Related Documents ..................................................................................................................................... 46 8 Glossary ...................................................................................................................................................... 46 9 Document Revision History ......................................................................................................................... 47 Table of Figures Figure 2.1 ZSSC3027 Functional Block Diagram ........................................................................................... 12 Figure 2.2 ADC Offset ..................................................................................................................................... 17 Figure 3.1 Operational Flow Chart: Power Up ................................................................................................ 21 Figure 3.2 Operational Flow Chart: Command Mode and Normal Mode ....................................................... 22 Figure 3.3 SPI Configuration CPHA=0 ........................................................................................................... 26 Figure 3.4 SPI Configuration CPHA=1 ........................................................................................................... 27 Figure 3.5 SPI Command Request ................................................................................................................. 27 Figure 3.6 SPI Read Status ............................................................................................................................ 28 Figure 3.7 SPI Read Data ............................................................................................................................... 28 Figure 3.8 I2C™ Command Request .............................................................................................................. 29 Figure 3.9 I C™ Read Status .......................................................................................................................... 29 2 2 Figure 3.10 I C™ Read Data ............................................................................................................................ 30 Figure 3.11 Memory Program Operation .......................................................................................................... 31 Figure 4.1 ZSSC3027 Pad Assignments ........................................................................................................ 44 List of Tables Table 1.1 Maximum Ratings ............................................................................................................................ 7 Table 1.2 Operating Conditions ....................................................................................................................... 7 Table 1.3 Requirements for VDD Power-on Reset .......................................................................................... 8 Table 1.4 Electrical Parameters ....................................................................................................................... 8 Table 2.1 Amplifier Gain: Stage 1 .................................................................................................................. 13 Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Table 2.2 Amplifier Gain: Stage 2 .................................................................................................................. 13 Table 2.3 Gain Polarity .................................................................................................................................. 14 Table 2.4 MSB/LSB Segmentation Settings for Bridge Measurement .......................................................... 15 Table 2.5 MSB/LSB Segmentation Settings for Temperature Measurement ................................................ 15 Table 2.6 ADC Conversion Times for a Single A2D Conversion................................................................... 15 Table 2.7 Typical Conversion Times vs. Noise Performance for 16-Bit Results with Full Sensor Signal Conditioning for AZBM, BM, AZTM, and TM ................................................................................. 16 Table 2.8 ADC Offset Settings for the Measurement Configuration Register BM_config ............................. 17 Table 3.1 SPI/I C™ Commands .................................................................................................................... 23 Table 3.2 Get_Raw Commands .................................................................................................................... 24 Table 3.3 General Status Byte ....................................................................................................................... 25 Table 3.4 Status Byte for Read Operations ................................................................................................... 25 Table 3.5 Status Byte for Write Operations ................................................................................................... 25 Table 3.6 Mode Status ................................................................................................................................... 26 Table 3.7 Memory Status Word ..................................................................................................................... 31 Table 3.8 MTP Memory Content Assignments .............................................................................................. 32 Table 4.1 Pad Assignments ........................................................................................................................... 44 2 Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 1 IC Characteristics 1.1. Absolute Maximum Ratings Note: The absolute maximum ratings are stress ratings only. The ZSSC3027 might not function or be operable above the recommended operating conditions. Stresses exceeding the absolute maximum ratings might also damage the device. In addition, extended exposure to stresses above the recommended operating conditions might affect device reliability. ZMDI does not recommend designing to the “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 Input Current into any Pin Except SDA, CLK 1) and Supply Pins 2) Electrostatic Discharge Tolerance – Human Body Model (HBM1) Storage Temperature 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 1) Latch-up current limit for SCLK/SCL and MOSI/SDA: ±70mA. 2) Latch-up resistance; reference for pin is 0V. 3) HBM1: C = 100pF charged to VHBM1 with resistor R = 1.5k 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 The reference for all voltages is Vss. Table 1.2 Operating Conditions PARAMETER SYMBOL MIN TYP MAX UNIT Supply Voltage VDD 1.7 - 3.6 V VDD Rise Time tVDD 200 μs Bridge Current IVDDB 1.8 Operation Temperature Range—Standard External capacitance between VDDB and VSS Data Sheet August 24, 2014 mA 16.5 TAMB -40 CL 0.01 - © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 85 °C 50 nF 7 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC A dynamic power-on-reset circuit is implemented in order to achieve minimum current consumption in idle mode. The VDD low level and the subsequent rise time and VDD rising slope must meet the requirements in Table 1.1 to guarantee an overall IC reset; lower VDD low levels allow slower rising of the subsequent on-ramp of VDD. Other combinations might also be possible. For example, the reset trigger can be influenced by increasing the powerdown time and lowering the VDD rising slope requirement. Table 1.3 Requirements 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) 1.3. Electrical Parameters All parameter values are valid only under the specified operating conditions. All voltages are referenced to Vss. Table 1.4 Electrical Parameters Note: See important table notes at the end of the table. Parameter Symbol Conditions/Comments Min Typ Max Unit 1.60 1.67 1.74 V Active State, average 930 1500 µA Sleep State, idle current 20 250 nA Supply Bridge Supply Voltage, ADC Reference Voltage VDDB Current Consumption IVDD Power Supply Rejection 20·log10(VDD/VDDB) (see section 1.4) PSRVDD Memory Program Voltage Internally generated VDD = 1.8V 17 dB VDD = 2V 32 dB VDD,prog Required voltage level at VDD pin 2.9 Mean Program Current IVDD,prog Mean current consumption during multiple-time memory (MTP) programming cycle at VDD 6 Peak Program Current Iprog,max MTP program at VDD pin, dynamic switch-on current draw Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 3.6 V mA 20 mA 8 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Parameter Symbol Conditions/Comments Min Typ Max Unit 16 Bit 1.08 MHz Analog-to-Digital Converter (ADC, A2D) Resolution rADC 10 ADC Clock Frequency fADC Internal ADC clock Reference Voltage n Vrefn See section 2.3.2. VDDB * 0.03 Reference Voltage p Vrefp See section 2.3.2. VDDB * 0.97 Offset A2D_Offset 8-step programmable offset Integral Nonlinearity (INL) INLADC Tested / verified within design -4 - +4 LSB Differential Nonlinearity DNLADC Tested / verified within design -1 - +1 LSB Conversion Rate, 16-Bit Single fS,raw Conversions per second for single 16-bit A2D conversion 6 - 355 Hz 0.92 1 1/16 8/16 Amplifier Gain Gamp 32 steps 13.2 Gain Error Gerr Referenced to nominal gain -2.5 72 - 2.5 % 0.01 %FSO 3 175 Hz 0.65 1.05 V 50 kΩ 999 Ω Sensor Signal Conditioning Performance IC Accuracy Error 1) ErrA,IC Conversion Rate, 16-Bit SSC fS, SSC Accuracy error for ideally linear sensor (temperature and measurand) Conversion per second for fully corrected 16-bit measurement Input Input Voltage Range Bridge Resistance VINP, VINN Input voltage range at INP and INN RBR Full power supply disturbance rejection (PSRR) capabilities Reduced PSRR, but full functionality 1 10 100 Power-Up tSTA1 VDD ramp up to interface communication (see section 3.1) 1 ms tSTA2 VDD ramp up to analog operation 2.5 ms tWUP1 Sleep to Active State interface communication 0.5 ms tWUP2 Sleep to Active State analog operation 2 ms Start-up Time Wake-up Time Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Parameter Symbol Conditions/Comments Min Typ Max Unit 3.7 4 4.3 MHz Oscillator Internal Oscillator Frequency fCLK Internal Temperature Sensor For both temperature ranges: -40°C to +85°C Temperature Resolution 0.003 K/LSB Interface and Memory SPI Clock Frequency fC,SPI I²C™ Clock Frequency fC,I2C Program Time Data Retention 1.4. tprog 2) tRET_MTP Maximum capacitance at MISO line: 40pF @ VDD=1.8V MTP programming time per 16-bit register 1000h @ 125°C 500 10 20 MHz 3.4 MHz 600 µs a 1) Percentage referred to maximum full-scale output (FSO); e.g. for 16-bit measurements: ErrA,IC [%FSO] = 100 · MAX{ | ADCmeas – ADCideal | } / 216. 2) With maximum ambient temperature of 125°C. Power Supply Rejection Ratio (RSRR) vs. Frequency Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 2 Circuit Description 2.1. Brief Description The ZSSC3027 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 a multiple-time programmable (MTP) memory (see section 2.4.2 regarding limitations). The ZSSC3027 can be configured for a wide range of resistive bridge sensor types. A 2 digital interface (SPI or I C™*) enables communication. The ZSSC3027 supports two operational modes: Normal Mode and Command Mode. Normal Mode is the standard operating mode. Typically in Normal Mode, the ZSSC3027 wakes up from a Sleep State (low power), runs a measurement in Active State, and automatically returns to the Sleep State. (See section 3.3 for details on operational modes.) 2.2. Signal Flow and Block Diagram See Figure 2.1 for the ZSSC3027 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. The Temperature Reference Sensor block is based on a resistive sensing element. * I2C™ is a trademark of NXP. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Figure 2.1 ZSSC3027 Functional Block Diagram VDDB Vreg int VTP VTN Temperature Reference Sensor VDD AGND / CM Generator Bias Current Generator Power Ctr. Voltage Regulator VSS Sensor Bridge INP INN Multiplexer ZSSC3027 A PreAmplifier D 18-bit DSP Core (Calculations, Communication) 16 Bit VSSB SPI Power-ON Reset Clock Generator Ring Oscillator EOC System Control Unit MTP ROM I²CTM SCLK/SCL SS MOSI/SDA MISO SEL 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 ZSSC3027 employs a 2-stage 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 bits 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 offset and the sensor element offset, i.e., the overall system offset for the 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 ZSSC3027 supports SPI and I C™ interface communication for controlling the ZSSC3027, configuration, and measurement result output. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 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 (address 10HEX; see section 3.6.3) 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 BM_config Bit G1 BM_config 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 BM_config Bit G4 BM_config Bit G3 BM_config 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 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, which is bit 5 in the BM_config register (see section 3.6.3). 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 applying a sensor to the ZSSC3027 with swapped input signals at INN and INP; e.g., to avoid crossing wires for the final sensor module’s assembly. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Table 2.3 Gain Polarity Gain_polarity (BM_config Bit 5) 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. The optimal gain (and offset) setup for a specific sensor element can be determined by these steps: 1) Collect sensor elements’ characteristic, statistical data (over temperature, ambient sensor parameter, and over production tolerances): a. Minimum differential output voltage: Vmin b. Maximum differential output voltage: Vmax Note: The best possible setup can only be determined if the absolute value of V max is bigger than the absolute value of Vmin. If this is not the case, the gain polarity should be reversed. 2) If Vmin and Vmax have different signs (normally: Vmax is positive and Vmin is negative), then the required ADC offset shift can be selected using this ratio: RatioOffset = |Vmin| / (Vmax – Vmin). In this case, the respective offset setup (A2D_offset) is the nearest integer of multiples of 1/16 in the th range of 1/16 to 8/16 (see Table 2.8): A2D_offset = Round_to_x16 {RatioOffset}. 3) Determine which of the two following cases is valid. a. If RatioOffset – A2D_offset ≤ 0 then calculate Theoretical optimum gain: Gainopt =(1 – A2D_offset) * Vref / Vmax b. If RatioOffset – A2D_offset > 0 then calculate Theoretical optimum gain: Gainopt = A2D_offset * Vref / |Vmin| with: Vref = Vrefp – Vrefn = 0.94·VDDB,min 1.5V Finally, select the setup gain (Gainsetup) as the nearest gain to Gainopt, where Gainsetup ≤ Gainopt. 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 final ADC resolution is determined by MSB + LSB. For the bridge measurement, the MSB-LSB segmentation is programmable via the Msb and Lsb settings in the BM_config register (10HEX; see section 3.6.3) stored in the MTP memory (see section 2.4.2). For the temperature measurement, the MSB-LSB segmentation is programmable via the Temp_ADC settings in the BM_config register. MSB LSB The conversion time is proportional to 2 +2 . During the MSB coarse conversion, the ADC input signal is MSB sampled and integrated 2 times, resulting in inherit low-pass behavior and noise suppression. The longer the MSB coarse conversion is, the better the noise suppression is. Possible settings are listed below in Table 2.4 and Table 2.5. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Table 2.4 MSB/LSB Segmentation Settings for Bridge Measurement Msb Setup Bits [7:6] in BM_config Number of MSB Coarse Conversion Bits Lsb Setup Bits [9:8] in BM_config Number of LSB Fine Conversion Bits 00BIN 10 00BIN 0 01BIN 12 01BIN 2 10BIN 14 10BIN 4 11BIN 16 11BIN 6 Table 2.5 MSB/LSB Segmentation Settings for Temperature Measurement Temp_ADC Setup Bits [14:13] in BM_config Number of MSB Coarse Conversion Bits Number of LSB Fine Conversion Bits 01BIN 16 0 10BIN 10 6 11BIN 12 4 Setup according to ZMDI configuration in reserved memory (recommended setup for best performance and speed trade-off) 00BIN Table 2.6 gives the ADC conversion times for the MSB/LSB settings (yellow indicates 16-bit setups). Useful MSB/ LSB setups are with LSB = 0 (MSB-only conversions) or combinations that result in MSB + LSB ≤ 16. Resolutions beyond 16-bit mainly digitize the collected front-end noise and typically do not improve the system performance. Table 2.6 ADC Conversion Times for a Single A2D Conversion MSB [Bits] LSB [Bits] 10 0 1170 12 0 4625 14 0 18450 16 0 73745 10 2 1180 12 2 4635 14 2 18460 10 4 1200 12 4 4660 10 6 1300 Data Sheet August 24, 2014 Bridge or Temperature Measurement Conversion Time in s (typical) © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 15 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Table 2.7 shows the trade-off between noise performance and typical conversion time for 16-bit results for a signal that has been fully conditioned using 4 single measurements: the auto-zero bridge measurement (AZBM), the bridge measurement (BM), auto-zero temperature measurement (AZTM), and temperature measurement (TM). Table 2.7 Typical Conversion Times vs. Noise Performance for 16-Bit Results with Full Sensor Signal Conditioning for AZBM, BM, AZTM, and TM Note: The pink shading indicates ZMDI’s recommended ADC segmentation for temperature sensor measurement. ADC Segmentation: Temperature Sensor [MSB/LSB] 1) Typical Measurement Typical 3-Sigma Noise for ADC Segmentation: Bridge 1) Duration, MEASURE, (ACHEX) SSC-Corrected Output Sensor [MSB/LSB] [ms] [counts] 10 / 6 10 / 6 5.8 9.6 10 / 6 12 / 4 13.2 7.4 10 / 6 14 / 2 43.0 6.8 10 / 6 16 / 0 165 6.6 12 / 4 10 / 6 13.2 9.5 12 / 4 12 / 4 20.5 7.3 12 / 4 14 / 2 50.5 6.7 12 / 4 16 / 0 170.3 6.3 16 / 0 10 / 6 162.6 8.1 16 / 0 12 / 4 170.3 6.6 16 / 0 14 / 2 200.3 5.3 16 / 0 16 / 0 319.5 5.2 Reference noise values were obtained with this setup: 17kΩ sensor bridge, 25°C, Gain=54, ADC shift=-1/16 through 15/16 (see below), VDD=1.8V. 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 and references voltages Vrefn and Vrefp are shown in Figure 2.2, where VAGND VDDB/2. The ADC offset is controlled by the A2D_Offset setting bits [12:10] in the Measurement Configuration Register BM_config (10HEX; see section 3.6.3) in the MTP memory (see section 2.4.2). The ADC offset settings are listed in Table 2.8. See section 1.4 for typical values for Vrefn and Vrefp. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 16 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Figure 2.2 ADC Offset ADCout 1 VINP, A2D_Offset = 1/16 VINN, A2D_Offset = 1/16 8/16 VINP, A2D_Offset = 8/16 A2D_Offset VINN, A2D_Offset = 8/16 1/16 0 Table 2.8 Vrefn VAGND Vrefp VIN, VIP ADC Offset Settings for the Measurement Configuration Register BM_config Z2 Z1 Z0 (BM_config bit 12) (BM_config bit 11) (BM_config bit 10) 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 August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 17 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 2.3.3. Temperature Measurement The ZSSC3027 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 the 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 noise immunity or conversion time (see section 2.3.2). 2.3.4. Bridge Supply The ZSSC3027 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 ZSSC3027’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 needs to be updated, normally a new page must be selected by increasing the page counter and the whole memory content must 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 internally in the ZSSC3027 whereas increased ZSSC3027 power supply requirements must be fulfilled during programming (see Memory Programming Voltage in section 1.3). There is no over-write or erase function for the MTP memory. See section 3.4.1 for further details. The physical memory function is such that each single bit that has not yet been set to 1 (i.e., remains 0) can still be changed to 1, so it is possible to (partially) re-program an MTP register as shown in the following example: Assume MTP address 11HEX was written with 8421HEX which is 1000 0100 0010 0001BIN. Changing the register contents to A6A7HEX (i.e., 1010 0110 1010 0111binary) can be achieved by either writing A6A7HEX (any already written bit will be ignored automatically) or just writing the difference compared to 8421HEX, which is 2286HEX. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 18 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 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; e.g., this is not the case for contentold = FFFFHEX and contentnew ≠ FFFFHEX. Depending on the former and the newly intended MTP addresses and register contents, a re-programming could be possible. 2.4.3. Clock Generator The clock generator, implemented as a ring oscillator, provides a 4MHz clock signal. The frequency is trimmed during production test. 2.4.4. Power Supervision The power supervision block as a part of the voltage regulator combined with the digital section 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 ZSSC3027 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 2 SEL = 1 -> I C™ Mode If the SEL pin is not connected, I²C™ communication will be selected (IC-internal pull-up at SEL pin). The SPIspecific pins (SS, MISO) do not need to be connected for I²C™ operation. To also provide interface accessibility in Sleep State (all 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 August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 19 of 47 ZSSC3027 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 ZSSC3027 communication interface is able to receive the first command after a time t STA1 from when the VDD supply is within operating specifications. The ZSSC3027 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 (see section 3.3) after receiving the activating command is defined as tWUP1 and tWUP2 (see section 1.3). In Command Mode, subsequent commands can be sent after tWUP1. The first measurement starts after tWUP2 if a 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 block 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, and TM followed by a signal correction calculation. 3.3. Operational Modes Figure 3.1 illustrates the ZSSC3027 power-up sequence and subsequent operation depending on the selected 2 interface communication mode (I C™ or SPI) as determined by the SEL pin voltage level (see section 2.4.5). With either interface, after the voltage regulators are switched on, the ZSSC3027’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 ZSSC3027 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). See Table 3.1 for definitions of the commands. Figure 3.2 shows the ZSSC3027 operation in Normal Mode and Command Mode including when the LV and HV sections are active as indicated by the color legend. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 20 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC The Normal Mode automatically returns to Sleep State after executing the requested measurements. In Command Mode, the ZSSC3027 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 first command received after POR. Figure 3.1 Operational Flow Chart: Power Up IC Power On I2C™ Interface SPI Interface IO_mode = I2CTM yes (I2CTM) SEL==1 no (SPI) IO_mode = SPI Command: load IC-I²C Addr. Switch off pull-up at SEL Power up LV Command: load I/O setup Data/Status from LV LV Operation Save: IC I²C Address / Data / Status Power up LV CommandMode ==active yes Save: Setup / Data / Status no Power down (switch off LV and wait for command) CommandMode ==active yes no Data/Status from LV LV Operation Power down (switch off LV and wait for command) Receive: Command Received I²C Slave_Addr == IC I²C Slave_Addr no no no yes SS == 1 Read_bit == 1 (Data fetch) no yes Receive: Command yes Execute: Data Fetch Received CMD == Read_DF yes Color Legend: Execute: Data Fetch LV-Operation Data Sheet August 24, 2014 HV-Operation © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 21 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Figure 3.2 Operational Flow Chart: Command Mode and Normal Mode Start LV Get command from HV CM active CMD==Start_CM yes Receive: Command no INVALID_CMD Case (Command) Start_NOM Case (Command) CM inactive INVALID_CMD Execute: Command REGULAR_CMD Data/Status from LV Data/Status from LV REGULAR_CMD Execute: Command LV Operation HV Operation End LV Sleep Mode 3.4. 3.4.1. Color Legend: Command Mode Command Interpretation 2 SPI/I C™ 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). Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 22 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 2 The SPI/I C™ commands supported by the ZSSC3027 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. There is a ZMDI-reserved section of memory that can be read but not over-written by the user. Table 3.1 2 SPI/I C™ Commands Note: Every return starts with a status byte followed by the data word as described in section 3.5.1. Command (Byte) Return Description Normal Mode Command Mode 00HEX to 17HEX 16-bit user data Read data in the user memory address (00HEX to 17HEX) matching the command (might not be using all addresses). yes yes 20HEX to 37HEX 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 followed by 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 (second set of addresses 00HEX to 0EHEX respectively). no yes 80HEX to 8EHEX 16-bit ZMDI-reserved memory status Read memory status bytes for ZMDIreserved memory data at address specified by command minus 80HEX (second set of addresses 00HEX to 0EHEX respectively; see section 3.6.2 for a description of the memory status bytes). no yes 5EHEX — Increment user memory page pointer. no yes A0HEX to A7HEX followed by 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 A8HEX — Start_NOM Exit Command Mode and transition to Normal Mode. no yes A9HEX — Start_CM Exit Normal Mode and transition to Command Mode. yes no Data Sheet © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. (see Table 3.2) August 24, 2014 23 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Command (Byte) Return Description Normal Mode Command Mode AAHEX — Write_ChecksumC If not yet written, the checksum for the valid user MTP page is calculated and written to MTP. no yes ACHEX 16-bit fully corrected bridge measurement data + 16-bit corrected internal temperature Measure Triggers full measurement cycle (AZBM, BM, AZTM, and TM, as described in section 3.2) and calculation and storage of data in interface (configurations from MTP). yes yes FXHEX Status followed by last data NOP Only valid for SPI (see 3.5.1 and 3.5.2). yes yes Table 3.2 Get_Raw Commands Command Measurement AFE Configuration Register A0HEX followed by 0000HEX BM – Bridge Measurement BM_Config A1HEX followed by 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 according to the definitions for BM_Config. A2HEX followed by 0000HEX BM-AZBM – Auto-Zero Corrected 1) Bridge Measurement BM_Config A3HEX followed by ssssHEX BM-AZBM – Auto-Zero Corrected 2) 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 according to the definitions for BM_Config. A4HEX followed by 0000HEX TM – Temperature Measurement ZMDI-defined register A5HEX followed by 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 according to the definitions for BM_Config being valid for temperature measurement in this case (bits [15:13] will be ignored). A6HEX followed by 0000HEX TM-AZTM – Auto-Zero Corrected 1) Temperature Measurement ZMDI-defined register A7HEX followed by ssssHEX TM-AZTM – Auto-Zero Corrected 2) 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 according to the definitions for BM_Config being valid for temperature measurement in this case (bits [15:13] will be ignored). 1) Recommended for raw data collection during calibration coefficient determination using measurement setups pre-programmed in MTP. 2) Recommended for raw data collection during calibration coefficient determination using un-programmed (i.e., not in MTP), external measurement setups; e.g., for evaluation purposes. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 24 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 3.5. Communication Interface 3.5.1. Common Functionality Commands are handled by the command interpreter in the low-voltage (LV) section. Commands that need additional data are not treated differently than other commands because the high-voltage (HV) interface is able to buffer the command and all the 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. 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 ZSSC3027 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 ZSSC3027 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 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 3 Mode 2 1 0 Memory error? Internal data transfer Special 2 1 0 Memory error? Data corrected? ALU saturation? Status Byte for Read Operations Bit 7 6 5 Meaning 0 Powered? Busy? Table 3.5 4 4 3 Mode Status Byte for Write Operations Bit 7 6 5 Meaning 0 Powered? Busy? Data Sheet August 24, 2014 4 3 Mode 2 Memory error? 1 Memory full? MTP write reject? © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 0 Don’t care 25 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Table 3.6 Mode Status Status[4:3] Mode 00 Normal Mode 01 Command Mode 10 ZMDI-Reserved 11 Command Mode and Reserved Further status information is provided by the EOC pin. The EOC pin is set when a measurement and calculation have been completed. 3.5.2. SPI The SPI Mode is available when the SEL pin = 0. The polarity and phase of the SPI clock are programmable via the CKP_CKE setting in address 02HEX as described in Table 3.8. CKP_CKE is two bits: CPHA (bit 10), which selects which edge of SCLK latches data, and CPOL (bit 11), which indicates whether SCLK is high or low when it is idle. The polarity of the SS signal and pin are programmable via the SS_polarity setting (bit 9). 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 Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 26 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 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 sent. The status can be read at any time with the NOP command (see Figure 3.7). 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. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 27 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 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 August 24, 2014 MOSI Command = NOP 00HEX 00HEX 00HEX 00HEX MISO Status BridgeDat <15:8> BridgeDat <7:0> TempDat <15:8> TempDat <7:0> © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 28 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 3.5.3. 2 I C™ 2 2 I C Mode is selected by the SEL pin = 1. In I C Mode, each command is started as shown in Figure 3.8. Only the number of bytes that is needed for the command must be sent. An exception is the HS-mode where 3 bytes must always be sent as 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. Figure 3.8 I2C™ Command Request 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 2 Figure 3.9 I C™ Read Status Read Status (I2C™ Read) S SlaveAddr 1 A Status N P read Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 29 of 47 ZSSC3027 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 ZSSC3027’s interface. In I²C-High-Speed Mode, a command consists of a fixed length of three bytes. 3.6. Memory In the ZSSC3027, 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 a total of 4 pages. Resetting the page counter is not possible. The page counter starts with 0 and th can be incremented to a maximum of 3. 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 the customer ID, interface setup data, measurement setup information, and calibration coefficients, etc. ZMDI Page: Only accessible for write operations by ZMDI. The ZMDI page contains specific trim information and is programmed during manufacturing test by ZMDI. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 30 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 3.6.1. Programming Memory Programming memory requires a specific supply voltage level (>2.9V) at the VDD pin (see section 1.3 for specifications). The MTP programming voltage itself is generated by means of an implemented charge pump, generating an internal memory programming voltage (VPP); no additional, external voltage, other than VDD needed. The program timing is shown in Figure 3.11. Supplying the ZSSC3027 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 contents. Figure 3.11 Memory Program Operation command Start_CM MemWr VPP 3.6.2. MemWr tVPP MemWr MemRd tVPP MemWr memory write customer address MemRd memory read customer address 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 13 12:0 Data Sheet August 24, 2014 Description Data was corrected (0: no, 1: yes) Current page Undefined – do not use © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 31 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 3.6.3. Memory Contents Table 3.8 MTP Memory Content Assignments MTP Address 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) Interface Configuration 6:0 000 0000BIN Slave_Addr 8:7 00BIN - I²C™ slave address; valid range: 00HEX to 7FHEX (default: 00HEX) Note: address codes 04HEX to 07HEX are reserved for 2 entering the I C™ High Speed Mode. Reserved Determines the polarity of the Slave Select pin (SS) for SPI operation: 9 0BIN SS_polarity 02HEX Clock polarity and clock-edge select—determines polarity and phase of SPI interface clock with the following modes: 11:10 00BIN CKP_CKE 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 15:12 Data Sheet August 24, 2014 0 Slave Select is active low (SPI and ZSSC3027 are active if SS==0) 1 Slave Select is active high (SPI and ZSSC3027 are active if SS==1) - Not assigned © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 32 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC MTP Address Word / Bit Range Default Setting Description Notes / Explanations Signal Conditioning Parameters 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 17-bit 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 the 17-bit coefficient’s absolute value Tcg_sign Sign of 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 the 17-bit 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 the 17-bit coefficient’s absolute value SOT_tco_sign Separate sign setting for 2 -order temperature coefficient (SOT_tco): 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 the 17-bit coefficient’s absolute value st 4 0BIN st 5 0BIN 03HEX st 6 0BIN st 7 0BIN nd 8 0BIN nd 9 0BIN nd 10 Data Sheet August 24, 2014 0BIN © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 33 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC MTP Address Word / Bit Range Default Setting Description Notes / Explanations nd 11 0BIN SOT_tcg_sign Separate sign setting for 2 -order temperature coefficient (SOT_tcg): 0 => a positive value or 1 => a negative value 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 the 17-bit coefficient’s absolute value SOT_bridge_sign Separate sign setting for 2 -order bridge coefficient (SOT_bridge): 0 => a positive value or 1 => a negative value nd 12 0BIN nd 13 0BIN Type of second-order curve correction for the bridge sensor signal. 14 0BIN SOT_curve 15 0BIN TSETL_sign Separate sign setting for T_SETL: 0 => a positive value or 1 => a negative value 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 the 17-bit coefficient’s absolute value Gain_T_sign Separate sign setting for the temperature gain (Gain_T): 0 => a positive value or 1 => a negative value SOT_T[16] 2 -order temperature coefficient of temperature sensor, bit[16] — functions as the MSB and combines with SOT_T[15:0] in 0EHEX to form the 17-bit coefficient’s absolute value SOT_T_sign Separate sign setting for 2 -order temperature coefficient (SOT_T): 0 => a positive value or 1 => a negative value Offset_T[16] Temperature offset of temperature sensor, bit[16] — functions as the MSB and combines with Offset_T[15:0] in 0CHEX to form the 17-bit coefficient’s absolute value Offset_T_sign Separate sign setting for the temperature offset (Offset_T): 0 => a positive value or 1 => a negative value - Not assigned 0 0BIN 1 0BIN 0 parabolic curve 1 s-shaped curve nd 2 0BIN nd 04HEX 3 0BIN 4 0BIN 5 0BIN 15:6 Data Sheet August 24, 2014 00 0000 0000BIN © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 34 of 47 ZSSC3027 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) Valid settings: [-1/16 to 15/16] = 7000HEX [-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 05HEX 15:0 0000HEX Offset_B[15:0] 06HEX 15:0 0000HEX Gain_B[15:0] Bits[15:0] of 17-bit wide absolute value of the bridge gain coefficient (the respective MSBs, Gain_B[16] and sign, Gain_B_sign, are under bits[3:2] in 03HEX) 07HEX 15:0 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) 08HEX 15:0 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) 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) Valid settings: 0CHEX Data Sheet August 24, 2014 15:0 0000HEX Offset_T[15:0] [-1/16 to 15/16] = 7000HEX [-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 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC MTP Address 0DHEX Word / Bit Range 15:0 Default Setting 0000HEX Description Notes / Explanations Gain_T[15:0] Bits [15:0] of the absolute value of the temperature gain coefficient (the respective MSBs, Gain_T[16] and sign, Gain_T_sign, are under bits[1:0] in 04HEX) 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: 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 10HEX 5 0BIN Gain_polarity 000 1.1 001 1.2 010 1.3 011 1.4 100 1.5 101 1.6 110 1.7 111 1.8 nd PREAMP stage with Set up the polarity of the sensor bridge’s gain (inverting of the chopper) with 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 Data Sheet August 24, 2014 00BIN (11BIN) Msb 00 10-bit 01 12-bit 10 14-bit 11 16-bit © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC MTP Address Word / Bit Range Default Setting Description Notes / Explanations Absolute number of bits for the LSB conversion in the ADC with Lsb: 9:8 00BIN Lsb 00 0-bit (single-stage ADC) 01 2-bit 10 4-bit 11 6-bit 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 15 00BIN 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) Temp_ADC - Reserved Customer Registers 11HEX Arbitrary customer use 12HEX Arbitrary customer use 13HEX Arbitrary customer use 14HEX Arbitrary customer use 15HEX Arbitrary customer use 16HEX Arbitrary customer use 17HEX Generated (checksum) for user page through a linear feedback shift register (LFSR); signature is checked with power-up to ensure memory content integrity Data Sheet August 24, 2014 15:0 - ChecksumC © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC The memory integrity checksum (referred to as CRC) 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. 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 ZSSC3027. There are three main steps to calibration: 1. Assigning a unique identification to the ZSSC3027. 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 ZSSC3027 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 ZSSC3027 as well as of the whole application. 3.7.1. Calibration Step 1 – Assigning Unique Identification Assign a unique identification number to the ZSSC3027 by using the memory write command (40HEX followed by two bytes of identification data and 41HEX followed by two bytes of identification data; see Table 3.1 and Table 3.8) to write the identification number to Cust_ID0 at memory address 00 HEX 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. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 38 of 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 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. measurand) be collected at the outer corners of the intended operation range or at least at points that are located far from each other. It is also essential to provide highly precise reference values as nominal, expected values. Note: The measurement precision of the external calibration-measurement equipment should be ten times more accurate than the expected ZSSC3027 output precision after calibration in order to avoid precision losses caused by the nominal reference values (e.g., measurand signal and temperature deviations). 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, three of the measurement pairs (at three different temperatures) 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: A2HEX + 0000HEX: Single bridge measurement for which the configuration register will be loaded from the BM_Config register (10HEX in MTP); preprogramming the measurement setup in the MTP is required. A3HEX + ssssHEX: Single bridge measurement for which the BM_Config configuration register (Gain, ADC, Offset, etc.) will be loaded as ssssHEX, which is sent as the data following the A3HEX command. For temperature values (grey text indicates values that are possible but will overwrite ZMDI settings): 3.7.3. A6HEX + 0000HEX: Single temperature measurement for which 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. A7HEX + ssssHEX: Single temperature measurement for which 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 ZSSC3027. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 3.8. The Calibration Math 3.8.1. Bridge Signal Compensation The saturation check in the ZSSC3027 is enhanced compared with older SSCs from ZMDI. Even saturation effects of the internal calculation steps are detected, allowing the final correction output to still be determined. It is possible to get potentially useful signal conditioning results even if there has been 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. 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 equations: T T _ Raw TSETL K1 215 T 215 SOT _ tcg T Tcg 15 2 K 2 Offset _ B BR _ Raw Z BP B (1) Gain _ B K1 15 K 2 215 215 2 Z BP SOT _ bridge Z BP 215 15 15 2 2 (2) T SOT _ tco T Tco 15 15 2 2 (3) (delimited to positive number range) (4) (delimited to positive number range) (5) Where 2 B = Corrected bridge reading output via I C™ or SPI; range [0HEX to FFFFHEX] BR_Raw = Raw bridge reading from ADC after AZ correction; range [-1FFFFHEX to 1FFFFHEX] Gain_B = Bridge gain term; range [-1FFFFHEX to 1FFFFHEX] Offset_B = Bridge offset term; range [-1FFFFHEX to 1FFFFHEX] Tcg = Temperature coefficient gain term; range [-1FFFFHEX to 1FFFFHEX] Tco = Temperature coefficient offset term; range [-1FFFFHEX to 1FFFFHEX] T_Raw = Raw temperature reading after AZ correction; range [-1FFFFHEX to 1FFFFHEX] Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC TSETL = T_Raw reading at which low calibration was performed (e.g., 25°C); range [-FFFFHEX to FFFFHEX] SOT_tcg = Second-order term for Tcg non-linearity; range [-1FFFFHEX to 1FFFFHEX] SOT_tco = Second-order term for Tco non-linearity; range [-1FFFFHEX to 1FFFFHEX] SOT_bridge = Second-order term for bridge non-linearity; range [-1FFFFHEX to 1FFFFHEX] ZBP Intermediary term = Complete equations: T T _ Raw TSETL 217 217 1 T K1 215 15 2 (6) 2 1 SOT _ tcg T Tcg 15 217 2 217 T K 2 Offset _ B BR _ Raw 15 2 217 1 217 217 1 217 (7) 2 1 17 2 1 SOT _ tco T Tco 15 217 2 17 2 17 217 1 217 217 1 217 217 1 217 Z BP B 15 2 217 1 2 1 SOT _ bridge 15 Z 2 BP 17 215 2 17 2 17 (8) 217 1 2 1 217 1 Gain _ B K1 15 K 2 215 2 17 215 2 17 2 0 17 Z BP 217 1 17 (9) 216 1 0 (10) Where Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC = absolute value ulll = bound/saturation number range from ll to ul; over/under-flow is reported as saturation in status byte Equations for the S-shaped SOT_curve setting (SOT_curve = 1): Simplified equations: Z BS B Gain _ B K1 15 K 2 215 2 (11) Z BS SOT _ bridge Z BS 215 215 15 15 2 2 (delimited to positive number range) (12) Complete equations: 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 Data Sheet August 24, 2014 (13) 2 1 215 217 17 217 1 2 1 SOT _ bridge Z 215 BS 15 2 217 17 2 17 216 (14) 0 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 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 equations: ZT Gain _ T T _ Raw Offset _ T 215 215 (delimited to positive number range) (15) T Z T SOT _ T Z T 215 215 215 (delimited to positive number range) (16) Complete equations: 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 Z T SOT _ T 15 T 15 15 Z T 2 2 2 217 17 2 0 17 (17) (18) Where Gain_T = Gain coefficient for temperature; range [-1FFFFHEX to 1FFFFHEX] T_Raw = Raw temperature reading after AZ correction; range [-1FFFFHEX to 1FFFFHEX] Offset_T = Offset coefficient for temperature; range [-1FFFFHEX to 1FFFFHEX] SOT_T = Second-order term for temperature source non-linearity; range [-1FFFFHEX to 1FFFFHEX] ulll = bound/saturation number range from ll to ul; over/under-flow is reported as saturation in status byte Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 4 Die Pad Assignments The ZSSC3027 is available in die form. See Figure 4.1 for pad assignments. Note that the ZMDI-test pads are for ZMDI use only. Figure 4.1 ZSSC3027 Pad Assignments Table 4.1 Pad Assignments Name Direction Type VDD IN Supply IC positive supply voltage for the ZSSC3027; regular bond pad VSS IN Supply Ground reference voltage signal VDDB OUT Analog Positive bridge supply INN IN Analog Negative bridge signal EOC OUT Digital End of conversion; regular bond pad Data Sheet August 24, 2014 Description © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Name Direction Type Description MISO OUT Digital Data output for SPI SCLK/SCL IN Digital Clock input for I²C™/SPI MOSI/SDA IN/Out Digital Data input for SPI; data in/out for I²C™ VSSB OUT Analog Negative bridge supply (bridge sensor ground) INP IN Analog Positive bridge signal SEL IN Digital I²C™ or SPI interface select SS IN Digital Slave select for SPI ZMDI-test - - Do not connect to these pads 5 Quality and Reliability The ZSSC3027 is available in a standard qualification version. For the standard version ZSSC3027CCxxx, all data specified parameters are guaranteed if not stated otherwise. 6 Ordering Sales Codes Sales Code Description Package ZSSC3027AC1B Die—temperature range: –40°C to +85 °C Wafer (304µm) unsawn, tested ZSSC3027AC6B Die—temperature range: –40°C to +85 °C Wafer (725µm) unsawn, tested ZSSC3027AC7C Die—temperature range: –40°C to +85°C Wafer (200µm) unsawn, tested ZSSC3027AI1D Engineering samples, Die—temperature range: –40°C to +85°C Dice in waffle pack (304µm) ZSSC3026-KIT Evaluation Kit for ZSSC3026, including boards, cable, software, and 1 ZSSC3026 PQFN24 sample. The ZSSSC3026 is equivalent to the ZSSC3027. ZMDI recommends using the ZSSC3026 Evaluation Kit to evaluate the capabilities of the ZSSC3027 because the ZSSC3027 is only available as die. Contact ZMDI Sales for additional information. Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC 7 Related Documents Note: X_xy refers to the latest version of the documents. Document File Name ZSSC3027 Feature Sheet ZSSC3027_FeatureSheet_Rev_X_xy.pdf ZSSC30x6 Evaluation Kit Documentation* ZSSC30x6_EvaluationKit_Rev_X_xy.pdf ZSSC30x6 Application Note—Calibration Sequence and DLL** ZSSC30x6_Calibration_Rev_X_xy.pdf * This document is applicable to both the ZSSC30x6 and ZSSC3027 and is included with the software for the ZSSC3026 Evaluation Kit. The software can be freely downloaded from the ZSSC3026 product page. ** This document is applicable to both the ZSSC30x6 ICs and the ZSSC3027, and it is available on the ZSSC3026 product page at www.zmdi.com/zssc3026. A free customer login is required to access this document. To establish a customer login, click on login in the upper right corner of the ZMDI website and follow the instructions. Visit the ZSSC3027 product page at www.zmdi.com/zssc3027 on ZMDI’s website www.zmdi.com or contact your nearest sales office for ordering information or the latest version of this document. 8 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) AZB 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 Data Sheet August 24, 2014 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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 47 ZSSC3027 Low-Power 16-Bit Sensor Signal Conditioner IC Term Description PreAmp Preamplifier SM Signal measurement SOT Second-order term TC Temperature coefficient (of a resistor or the equivalent bridge resistance) TM Temperature measurement 9 Document Revision History Revision Date Description 1.00 December 10, 2013 First release of data sheet. 1.01 August 24, 2014 Update for contact information. Minor edit for die description. Sales and Further Information www.zmdi.com [email protected] Zentrum Mikroelektronik Dresden AG Global Headquarters Grenzstrasse 28 01109 Dresden, Germany ZMD America, Inc. 1525 McCarthy Blvd., #212 Milpitas, CA 95035-7453 USA Central Office: Phone +49.351.8822.306 Fax +49.351.8822.337 USA Phone 1.855.275.9634 Phone +1.408.883.6310 Fax +1.408.883.6358 European Technical Support Phone +49.351.8822.7.772 Fax +49.351.8822.87.772 DISCLAIMER: This information applies to a product under development. Its characteristics and specifications are 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. European Sales (Stuttgart) Phone +49.711.674517.55 Fax +49.711.674517.87955 Data Sheet August 24, 2014 Zentrum Mikroelektronik Dresden AG, Japan Office 2nd Floor, Shinbashi Tokyu Bldg. 4-21-3, Shinbashi, Minato-ku Tokyo, 105-0004 Japan ZMD FAR EAST, Ltd. 3F, No. 51, Sec. 2, Keelung Road 11052 Taipei Taiwan Phone +81.3.6895.7410 Fax +81.3.6895.7301 Phone +886.2.2377.8189 Fax +886.2.2377.8199 Zentrum Mikroelektronik Dresden AG, Korea Office U-space 1 Building 11th Floor, Unit JA-1102 670 Sampyeong-dong Bundang-gu, Seongnam-si Gyeonggi-do, 463-400 Korea Phone +82.31.950.7679 Fax +82.504.841.3026 © 2014 Zentrum Mikroelektronik Dresden AG — Rev. 1.01 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. 47 of 47