MLX90326_12 Datasheet, PDF (8/13 Pages) Melexis Microelectronic Systems – Analog 0-5V Sensor Interface IC

MLX90326
Analog 0-5V Sensor Interface IC
8 Application Information
8.1 Ratio-metric mode with external temperature sensor.
The external temperature sensor is only needed for applications where the temperature surrounding the
customer sensor is different from the temperature surrounding the MLX90326. In the ratio-metric application
mode, to keep the accuracy, the same supply should be used for the customer sensor, the MLX90326 and an
ADC that makes the digital conversion of the analog output signal.
The C1 capacitor value (output) is typically 47nF. Range: 0 – 100nF.
The capacitor C2 on the FLT pin is optional. Typical value = 10nF. Range: 0 – 100nF. It is used to decrease
the noise and set the bandwidth of the system. The decoupling capacitors C3 between the supply and the
ground and C4 between output and supply have a typical value of 47nF.
The external resistor R1 is placed between the TMP pin and the supply. It is used as an external temperature
sensor. The external temperature sensor could be of type Panasonic, ERAS15J103V (R1 = 10k +/- 5%, TCR
= 1500ppm/degC +/- 200ppm/degC) for the -40ºC to 140ºC temperature range.
Typical pull up resistor R2 value is 2.4kOhm.
3901090326
Rev 002
Page 8 of 13
Data Sheet
Feb/12