MLX90320 Automotive Sensor Interface 1. Features and Benefits 2. Application Examples Suited cost optimized sensors: gain and Pressure transducers, strain gauges, offset correction by programmable accelerometers, position sensors, etc. coefficients Steering systems (e.g. torque sensors) Higher order temperature compensation Safety restraints systems (e.g. seat provided for both gain and offset occupant detection) External or internal temperature sensor Braking systems (e.g. ABS, force) for compensation of temperature errors Comfort systems (e.g. air conditioning) Over-voltage protection Engine management (e.g. injection) Fault detection and clamping levels Any bridge type sensor Ratio-metric output: 0 to 5V Single Pin Digital Programming Fully analog signal path RoHS compliant 3. Ordering information Product Code Temperature Package Code Option Code Packing Form Code Code RE L FR BBA-000 MLX90320 TU MLX90320 L FR BBA-000 Legend: Temperature Code: L for Temperature Range -40C to 150C Package Code: FR for SSOP 209 mil Packing Form: RE for Reel, TU for Tube Ordering example: MLX90320LFR-BBA-000-RE 4. Functional Diagram Wheatstone bridge on a sensing element, to large output voltage variations. VDD 7bits Over- & Reverse Optional clamping CSOF DAC Voltage Protection levels and fault POR detections The signal conditioning includes gain Ratiometric Chopping Chopping Oscillator: 4 MHz (+/- adjustment, offset control and second order INM + 15%) -> 250kHz dig Gdido Gdts - Gcs INP temperature compensation in order to IINV VDD FLT 1 2 10bits accommodate variations of the different DAC VDD TMP Application Select Fine Offset = 10bits resistive sensing elements. Compensation Fine Gain = Oo + O1.(T-T1) + O2.(T-T1) X2.117 Go + G1.(T-T1) + G2.(T-T1) DAC X(-1.667) mode Output Programming Fine Offset Fine Gain VDD mode I/O Go,G1,G2 values are stored in EEPROM and can be EEPROM TMP T TMP Oo,O1,O2 ADC ALU Go,G1,G2,Oo,O1,O2,T1, Gcs, Gain T1 10bits TMP Gdido, Gdts, IINV, TMP Select, Offset TMP Offset, TMP Gain, reprogrammed with an interface circuit and CSOF, CLKAdj, Clamp settings provided software. The MLX90320 is programmed with a single wire serial interface through the output pin. 5. General Description The MLX90320 covers the most typical resistive The user can specify on chip clamping levels type of Wheatstone bridge applications for use thus creating fault detection bands. By in an automotive environment. It is a monolithic intercepting various fault modes the MLX90320 silicon analog sensor interface that converts is able to inform about the reliability of its small changes in resistors, configured in a full analog output signal. REVISION 008 DECEMBER 2016 Page 1 of 34 3901090320 MLX90320 Automotive Sensor Interface Contents 1. Features and Benefits ............................................................................................................................ 1 2. Application Examples ............................................................................................................................. 1 3. Ordering information ............................................................................................................................. 1 4. Functional Diagram ............................................................................................................................... 1 5. General Description ............................................................................................................................... 1 6. Maximum ratings ................................................................................................................................... 4 7. Pad definitions and descriptions ............................................................................................................ 4 8. MLX90320 General Specifications ......................................................................................................... 6 9. Detailed Description ............................................................................................................................ 11 9.1. EEPROM ............................................................................................................................................. 12 9.2. The programmable clock................................................................................................................ 12 9.3. The temperature chain................................................................................................................... 13 9.4. The sensor signal chain................................................................................................................... 14 9.4.1. The Gain calibration of the sensor signal chain...................................................................... 15 9.4.2. The Offset calibration of the sensor signal chain.................................................................... 16 9.4.3. The output clamping levels ........................................................................................................ 18 9.4.4. The Faults detection ................................................................................................................... 18 9.5. Programming the MLX90320 through the output pin .................................................................... 20 9.5.1. Overview ..................................................................................................................................... 20 9.5.2. Communication Initialization Request ....................................................................................... 20 9.5.3. Communication Request ............................................................................................................ 21 9.5.4. Bit format .................................................................................................................................... 21 9.5.5. Commands .................................................................................................................................. 22 10. Unique Features ................................................................................................................................ 24 11. Typical applications circuits ............................................................................................................... 25 11.1. Ratio-metric mode with use of external temperature sensor................................................... 25 11.2. Ratio-metric mode without use of external temperature sensor.............................................. 26 11.3. Non Ratio-metric mode with use of external temperature sensor........................................... 26 11.4. Non Ratio-metric mode without use of external temperature sensor...................................... 27 12. EEPROM Contents ............................................................................................................................. 27 REVISION 008 DECEMBER 2016 Page 2 of 34 3901090320