MLX90320_12 Datasheet, PDF (26/33 Pages) Melexis Microelectronic Systems – Automotive sensor interface

MLX90320
Automotive sensor interface
8.4 Non Ratio-metric mode without use of external temperature sensor.
In this application mode the LM7805 generates the supply for the sensor, for the MLX90320 and for the ADC
used to convert the analog output signal in a digital value. C1, C2, C3, C4 and R2 are the same as in the non
ratio-metric application mode with external temperature sensor.
9 EEPROM Contents
Address
Decimal
0 to 2
3
Bits
EEPROM content
0 to 3 T1 for Gain DAC
0 to 3 CLKADJ[3..0]
4 to 6
7
7
0 to 3 G2 for Gain DAC
0
1 to 3
IINV
CG[2..0]
Comments
Contains the value of T1 used to calculate the fine gain
in order to operate the second order compensation of
the sensor span drift with temperature.
These bits are used to program the oscillator. If
CLKADJ[3:0] = 1111, the oscillator runs at the highest
frequency. If CLKADJ[3:0] = 0000, the oscillator runs at
the slowest frequency. This calibration is required to
calibrate the oscillator within +/-15% accuracy. A bad
oscillator calibration may cause malfunction of the
communication protocol thus it is only factory set.
Contains the second order fine gain coefficient used to
compensate the sensor sensitivity drift with temperature.
The MSB is the sign bit (two’s complement): If G2[11] =
1 then G2 is negative, if G2[11] = 0 then G2 is positive.
Bit used to invert the inputs
3 bits used to operate the coarse gain calibration.
CG[2:0] = 111 means maximum gain (13*5*1.9375) and
CG[2:0] = 000 means minimum gain (3.25*2*1.24).
3901090320
Rev 007
Page 26 of 33
Data Sheet
Feb/12