MELEXIS MLX90247B Datasheet

Features and Benefits

Solid state sensor
High reliability
Low cost, small size
On chip temperature sensor

Applications

Non-Contact Temperature Sensing
Differential Temperature Sensing
Climate Control
Ear, Temple Th ermometers
Household and Commercial Appliances

Ordering Information

Part No. Description

MLX90247B Thermopile with On-chip PTC Thermistor

MLX90247B

Thermopile w/On-Chip Thermistor

Functional Diagram

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Description

The MLX90247B is a thermopile sensor IC which
detects very small amounts of heat radiation. The
sensor consists of a membrane with a thermopile on
top of it.
The hot junctions of the thermopile are positioned
near the center of the membrane, the cold junctions
above the bulk silicon edge.
Due to the low thermal conductivity of the
membrane, absorbed heat will cause the
temperature to increase more at the center of the
membrane than at the edge above the bulk. This
temperature difference is converted to an electric
potential by the thermo-electric effect in the
thermopile junctions. No supply voltage is needed.

The sensor IC is integrated together with a PTC
thermistor in one silicon mass. The PTC is adjacent
to the cold junctions of the thermopile. As such, use
of the PTC is considered the more accurate method
of measuring thermopile cold junction temperature,
and thus overall sensor accuracy when making non­contact temperature measurement.

The sensor and thermistor can be used independent
of each other if desired, as the thermopile potential
is floating.

MLX90247B Discrete Infrared Sensor IC Page 1 Rev 1.0 17/Feb/01

MLX90247B

Thermopile w/On-Chip Thermistor

MLX90247B Electrical Specifications

DC Operating Parameters TA = -40oC to 150oC, (unless otherwise specified)

Parameter Symbol Test Condition Min Typ Max Unit

Thermopile Resistance Rtp @298K 44 59.5 75
Sensitivity S
TC of Sensitivity TCs @298K 0.1 %/K

Time constant T 30 ms
Thermistor Value Rptc

Thermal Coefficient PTC

(1) R(T)=R(298K).[1+A1.(T-298K)+A2.(T-298)2]
Note: when measuring resistances with an ohm meter, please take care that the internal protection diodes,

as indicated in the diagram below, are always reverse biased.

(1)

A1
A2

sensor @298K
black body @299K

@298K
25°C-100°C

29 42 55

18.2 26 33.8
5720 7150

11.57

8580 ppm/K

k

Ω

V/K

µ

k

Ω

ppm/K

2

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MLX90247B Absolute Maximum Ratings

Parameter Value Unit Comment

Operating temperature -40 ~ 150 °C Keep diode leakage in mind at high temperatures
Storage temperature -40 ~ 150 °C
Soldering temperature <220 °C t<5sec

MLX90247B Discrete Infrared Sensor IC Page 2 Rev 1.0 17/Feb/01