MLX90615SSG-DAA Melexis Inc, MLX90615SSG-DAA Datasheet - Page 18

• Manufacturer Part Number: MLX90615SSG-DAA
• Description: THERMOMETER IR DUAL 3V MED TO-46
• Manufacturer: Melexis Inc

Specifications of MLX90615SSG-DAA

• Featured Product: MLX90615 Series Infrared Thermometers
• Sensing Temperature: -40°C ~ 115°C
• Output Type: PWM, SMBus™
• Voltage - Supply: 2.6 V ~ 3.6 V
• Accuracy: ±0.5°C
• Package / Case: TO-46-4 Metal Can
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The IR sensor consists of series connected thermo-couples with cold junctions placed at thick chip substrate
and hot junctions, placed over thin membrane. The IR radiation absorbed from the membrane heats (or
cools) it. The thermopile output signal is
Where T
A is the overall sensitivity.
An additional sensor is needed for the chip temperature. After measurement of the output of both sensors,
the corresponding ambient and object temperatures can be calculated. These calculations are done by the
internal DSP, which produces digital outputs, linearly proportional to measured temperatures.
8.7.1 Ambient temperature Ta
The Sensor die temperature is measured with a PTAT element. All the sensors conditioning and data
processing is handled on-chip and the linearized sensor die temperature Ta is available in RAM (address
0x06).
The resolution of the calculated Ta is 0.02˚C. The sensor is factory calibrated for the range -20 to +85˚C.
Example:
Conversion RAM content to real Ta is easy done with following expression:
8.7.2 Object temperature T
The result has a resolution of 0.02 ˚C and is available in RAM (address 0x07). To is derived from RAM as:
3901090615
Rev 002
8.7 Principle of operation
RAM 0x06 = 0x3171 corresponds to -20,01˚C
RAM 0x06 = 0x45F3 corresponds to +84.99˚C
O
is the object absolute temperature (Kelvin), Ta is the sensor die absolute (Kelvin) temperature, and
O
V
T
T
ir
O
A
(
T
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°
A
K
K
Page 18 of 28
,
T
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O
=
=
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T
T
=
O
A
A
_ REG
_ REG
.
(
T
O
4
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. 0
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,
Infra Red Thermometer
12 Oct 2010
Data Sheet