MLX90621 datasheet(18/44 Pages) MELEXIS

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MLX90621

16x4 IR array

Datasheet

39001090621

Page 18 of 44

Datasheet IR16x4

Rev 3.0

15 September 2016

J‰†™žt is a scaling coefficient for the slopes of IR pixels offset and is stored in the EEPROM at

address 0xD9[3:0] as an unsigned value

/ is the ambient temperature calculated in 7.3.2

25>isaconstant

NOTE: This applies to the compensation pixel as well (

FP and FP while J‰†™žt is the same) with the only

difference being that

FP is stored in the EEPROM at addresses 0xD3 and 0xD4 as an unsigned value but not

calculated

Thermal Gradient Compensation (TGC)

9ŠL(J,•)` nno‡ˆtp‰™˜tš 9ŠL(J,•)_QII•-,FGŽ•-H•/,-{ 0 ¡ ∗ 9ŠL••eqq‰t˜no‡ˆtp‰™˜tš

Where:

9ŠL••eqq‰t˜no‡ˆtp‰™˜tš istheoffset compensated IRsignal ofthethermal gradient compensation

pixel

¡ 2¢Fbbdcef

¡ OOPLQ( is a coefficient stored at EEPROM address 0xD8 as a two’s complement value

Emissivity compensation

9ŠL(J,•)nefdb‚ƒ„`bi

y€c(r,•)` nno‡ˆtp‰™˜tš

Where:

¤ istheemissivitycoefficient.ThescaledvalueisstoredintoEEPROMasunsignedvalue

¤ 6M|∗£ZV£[

D6U|]

Calculating

¥¦§¨©(ª,«)

7.3.3.2

Œ•GŽ•(J,•) ¬1 4 1 ∗ ( / 0 /R)- ∗ ¬Œ(J,•) 0 ¡ ∗ ŒFP-

Where:

/ is the ambient temperature calculated in 7.3.2

/R is a constant = 25°C

1 is Ta dependence of Œ•GŽ•(J,•) stored in EEPRPOM at addresses 0xE6 and 0xE7 as two’s

complement value and the scale coefficient is fixed to be 20.

6M|∗_•2/ZV_•2/[

6ag

Œ(J,•)

au®∗¯oZk¯g[

a¯g‰†™žt V

∆¯(r,•)

a∆¯‰†™žt

6jmnopqrscts8u:v=

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