MLX90247 Datasheet, PDF (6/9 Pages) List of Unclassifed Manufacturers – Discrete Infrared Thermopile Detectors

MLX90247 family
Discrete Infrared Thermopile Detectors
8. Applications information
The output voltage of the thermopile is positive when the object is at higher temperature than the sensor;
it is negative when the object is at lower temperature than the sensor. As the output voltage can become
positive as well as negative, the sensor has to be connected to a differential amplifier that can accept both
positive and negative input signals. The figure below shows a solution using the MLX90313 infrared
sensor interface chip, which accepts common mode input voltages in the range [-0.1V;Vdd-3V]
IR+
IR-
Rsens
VSS
MLX90247
IRINP
VDD
IRINN
TINP
TINN
TEMPOUT
IROUT
MLX90313
CS
SCLK
SDI
SDO
REL1
CREF
VREFP
VSS
R3
5V
C3
TEMPOUT
IROUT
CS
SCLK
DIN
DOUT
REL
VREF
VSS/GND
MLX90601KZA-CKA
MLX90601KZA-CKD
MLX90601KZA-CLA
R3 = 100kΩ
C3 = 10µF
The figure below shows a typical application with the AD8628 low-offset low-drift differential opamp from
Analog Devices. The AD8628 has single voltage supply, and can only accept positive common mode
input signals. Vref sets the output offset (output voltage when To=Ta).
100Ω
100kΩ
5V
-
MLX90247DSA
+
60kΩ Vthermopile
Vref
3901090247
Rev. 004
Page 6 of 9
Data Sheet
Oct/07