MLX90320 Datasheet, PDF (22/32 Pages) Melexis Microelectronic Systems – Automotive small sensor interface

MLX90320
Automotive small sensor interface
7 Unique Features
Offset canceling
The offset of amplifier DIDO is cancelled by using a chopping mechanism. Also the
amplifier DTS and all sample-and-hold circuits make use of an offset canceling mechanism. This means
that the contribution of the on-chip offsets and offset drifts is negligible compared to the external sensor
offset and offset drift.
Coarse and fine second order calibration of the sensitivity and offset.
The MLX90320 can be calibrated to achieve 4V output span for a sensor output span in the 1.8mV/V to 63mV/V
and can compensate 0.4mV/V to 97.2mV/V input offset depending on the sensor output span and on the desired
MLX90320 output offset voltage. A wide range of sensor sensitivity and offset temperature drift can be
compensated with the second order fine gain and offset calibration.
Clamping levels and fault detection on signal
The user can program a low and a high output voltage clamping level and thus create fault bands. Thanks to the
fault bands creation, internal or external faults can be detected because they force the output voltage to go into a
fault band. See paragraph 6 for more detailed explanations.
EEPROM
All the calibration data is stored three times on an EEPROM and a majority voting is done when accessing data.
Parity check is used to diagnose data corruption. After all calibrations parameters were successfully written to
EEPROM, the EEPROM can be locked by sending a ‘Lock EEPROM’ command (see paragraph 6). This is
strongly recommended to avoid in application mode data corruption. For reliability reasons, actually each
calibration bit is stored three times in the EEPROM and the circuit uses a hardware majority voting system when
accessing data.
3901090320
Rev 004
Page 22 of 32
Data Sheet
Mar/05