MLX90323 420 mA Loop Sensor Interface with Signal Conditioning and EEPROM 1. Features and Benefits 2. Application Examples Programmable Sensor Interface IC with 4 Industrial pressure transducers to 20 mA current loop output Strain gauges, accelerometers, position Power supply from 6 to 35V sensors, etc. DC External or internal temperature sensor Any bridge type sensor with current loop for compensating temperature errors output 3. Ordering information Temperature Packing Form Product Code Package Code Option Code Code Code MLX90323 K DF AAA-000 TU MLX90323 K DF AAA-000 RE Legend: Temperature Code: K for Temperature Range -40C to +125C Package Code: DF for SOIC300Mil Packing Form: RE for Reel, TU for Tube Ordering example: MLX90323KDF-AAA-000-TU 4. Functional Diagram 5. General Description FET VDD1 OFC FLT The IC converts small changes of output voltage of VDD Supply Regulator full Wheatstone resistive bridge (caused by 3.5V mechanical stimulus such as pressure, force, torque, DAC Offset OPA light or magnetic field) to large changes of the IC 0V 2-bit output current. VBP CSGN x 35 x2 GAIN VBN 1.24kOhm 0.97V/V INV Hardware Gain = 70 It removes parasitic DC level (Offset) from the GAIN CMO 0.48V/V TMP CMN output bridge voltage and amplifies this signal Coarse Offset certain times (Gain). Offset and Gain are Fine Gain DAC IO1 Micro- IO2 Processor temperature dependent, so the IC allows COMS 3.5V External Temp Sensor temperature compensation of bridge parasitic DC ADC Internal Temp Sensor Temp Amp Gain GND 0V shift and sensitivity. Temperature can be GNTP 1:0 TSTB measured either by internal or external (resistor) temperature sensor. The values of Offset and Gain and their temperature dependency are gotten during the calibration process and are stored in the EEPROM. The IC has industry standard 4 20 mA current loop output interface and takes power directly from 2-wire signal line. The MLX90323 works properly over wide voltage range (from 6 to 35 V) at the signal line. REVISION 004 DECEMBER 2016 Page 1 of 26 3901090323 MLX90323 420 mA Loop Sensor Interface with Signal Conditioning and EEPROM Contents 1. Features and Benefits ............................................................................................................................ 1 2. Application Examples ............................................................................................................................. 1 3. Ordering information ............................................................................................................................. 1 4. Functional Diagram ................................................................................................................................ 1 5. General Description ............................................................................................................................... 1 6. Glossary of Terms................................................................................................................................... 3 7. Absolute Maximum Ratings.................................................................................................................... 4 8. Pin Definitions and Descriptions ............................................................................................................. 4 9. General Electrical Specifications ............................................................................................................. 6 10. Detailed General Description ............................................................................................................... 8 10.1. Understanding 4-20mA current loop interface ............................................................................... 8 10.2. Analog features ................................................................................................................................. 8 10.3. Digital features .................................................................................................................................. 9 10.4. Parameters calculation .................................................................................................................. 10 10.5. Communications ............................................................................................................................ 11 11. Temperature compensation ............................................................................................................... 13 12. Calibration.......................................................................................................................................... 16 12.1. Baseline Calibration ....................................................................................................................... 16 12.2. Temperature calibration ................................................................................................................ 16 12.3. Calibration procedure .................................................................................................................... 17 13. EEPROM and RAM byte definitions .................................................................................................... 18 14. Unique Features ................................................................................................................................. 23 15. Application Information ..................................................................................................................... 23 16. Standard information regarding manufacturability of Melexis products with different soldering processes ............................................................................................................................. 24 17. ESD Precautions ................................................................................................................................. 25 18. Package Information .......................................................................................................................... 25 19. Contact .............................................................................................................................................. 26 20. Disclaimer .......................................................................................................................................... 26 REVISION 004 DECEMBER 2016 Page 2 of 26 3901090323