MLX90621

16x4 IR array

Datasheet

39001090621

Page 3 of 44

Datasheet IR16x4

Rev 3.0

15 September 2016

Table of contents

1.

Table of contents.......................................................................................................................................................... 3

1.

Glossary of terms ......................................................................................................................................................... 5

2.

Absolute Maximum ratings .......................................................................................................................................... 5

3.

Pin definition and description ...................................................................................................................................... 6

4.

Electrical characteristics ............................................................................................................................................... 7

5.

Block diagram ............................................................................................................................................................... 8

6.

Principle of operation................................................................................................................................................... 9

7.

Initialization......................................................................................................................................................... 10

7.1.

Reading configuration .................................................................................................................................. 11

7.1.1.

Read measurement data (RAM data).................................................................................................................. 12

7.2.

PTAT data read ............................................................................................................................................. 12

7.2.1.

IR data read .................................................................................................................................................. 12

7.2.2.

Calculation........................................................................................................................................................... 14

7.3.

Calculation of absolute chip temperature Ta (sensor temperature) ........................................................... 14

7.3.1.

Example for Ta calculations.......................................................................................................................... 15

7.3.2.

Calculation of To........................................................................................................................................... 17

7.3.3.

Example for To calculations.......................................................................................................................... 20

7.3.4.

Detailed description, Block description...................................................................................................................... 23

8.

Pixel position ....................................................................................................................................................... 23

8.1.

MLX90621 address map ...................................................................................................................................... 24

8.2.

RAM.............................................................................................................................................................. 24

8.2.1.

Internal registers .......................................................................................................................................... 25

8.2.2.

Configuration register (0x92) ..................................................................................................................... 25

8.2.2.1

Trimming register (0x93) ............................................................................................................................ 26

8.2.2.2

EEPROM........................................................................................................................................................ 26

8.2.3.

POR...................................................................................................................................................................... 28

8.3.

ESD ...................................................................................................................................................................... 28

8.4.

Communication protocol ........................................................................................................................................... 28

9.

Communication pins ........................................................................................................................................... 28

9.1.

Low level communication protocol ..................................................................................................................... 29

9.2.

Start / Stop condition ................................................................................................................................... 29

9.2.1.

Device addressing......................................................................................................................................... 29

9.2.2.

Acknowledge ................................................................................................................................................ 29

9.2.3.

Low level communication operation............................................................................................................ 29

9.2.4.

Device modes ...................................................................................................................................................... 30

9.3.

Normal mode ............................................................................................................................................... 30

9.3.1.

Step mode .................................................................................................................................................... 30

9.3.2.

Power saving mode ...................................................................................................................................... 30

9.3.3.

Communication to IR array ................................................................................................................................. 31

9.4.

Start measurement command ..................................................................................................................... 31

9.4.1.

Read command ............................................................................................................................................ 31

9.4.2.

Write configuration register command........................................................................................................ 32

9.4.3.

Write trimming command............................................................................................................................ 32

9.4.4.

Communication to EEPROM................................................................................................................................ 33

9.5.

Performance Graphs ................................................................................................................................................ 34

10.

Temperature accuracy of the MLX90621 .......................................................................................................... 34

10.1.

Noise performance and resolution ................................................................................................................... 35

10.2.

Field Of View (FOV) ........................................................................................................................................... 36

10.3.

Applications Information.......................................................................................................................................... 37

11.

Use of the MLX90621 thermometer in I

11.1.