MLX90632 FIR sensor

Datasheet

Features and Benefits

 Small size

 Easy to integrate

 Factory calibrated

 External ambient and object temperature

calculation

 Measurement resolution of 0.02°C

 Supply voltage of 3.3V, supply current 1mA

(sleep current less than 2.5uA)

 I

C compatible digital interface

 Software definable I

C address with 1 LSB

bit external address pin

 Field of View of 50°

 Default refresh rate 0.5s, configurable

between 16ms and 2s

 Integrated post-calibration option

Application Examples

 Non-contact temperature measurements

 Temperature sensing element for

residential, commercial and industrial

building air conditioning

 Industrial temperature control of moving

parts

 Home appliances with temperature

control

Figure 1: Image of MLX90632

MLX90632 FIR sensor

Datasheet

Description

The MLX90632 is a non-contact infrared temperature sensor in a small SMD SFN package. The device is factory

calibrated with calibration constants stored in the EEPROM memory. The ambient and object temperature can

be calculated based on these calibration constants and the measurement data.

The MLX90632 is factory calibrated in the ambient temperature range from -20 to 85˚C and from -20 to 200˚C for

the object temperature range. The measured value is the average temperature of all objects in the Field Of View

of the sensor.

It is very important for the application designer to understand that these accuracies are guaranteed and

achievable when the sensor is in thermal equilibrium and under isothermal conditions (no temperature

differences across the sensor package).

The accuracy of the thermometer can be influenced by temperature differences in the package induced by

causes like (among others): Hot electronics behind the sensor, heaters/coolers behind or beside the sensor or by

a hot/cold object very close to the sensor that not only heats the sensing element in the thermometer but also

the thermometer package.

A major strength of the MLX90632 is that the measured effect of these temperature differences around the

sensor package is reduced to a minimum by the internal measurement algorithm.

In the same way, localized thermal variations -like turbulence in the air- will not generate thermal noise in the

output signal of the thermopile.

However, some extreme cases will influence the sensor.

The typical supply voltage of the MLX90632 is 3.3V. The communication with the chip is done by I

C in fast mode

plus (FM+). Through I

C the external microcontroller has access to the following blocks:

 RAM memory used for measurement data

 EEPROM used to store the trimming values, calibration constants and device/measurement settings

 Register to control the sensor

Based on this data, the external microcontroller can calculate the object temperature and if needed the sensor

temperature.

An optical filter (long-wave pass) that cuts off the visible and near infrared radiant flux is integrated in the sensor

to provide ambient light immunity. The wavelength pass band of this optical filter is from 2 till 14µm.