Infrared Thermometer - MLX90614

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Infrared Thermometer MLX90614.jpg

Melexis' MLX90614ESF-BAA is an infrared thermometer designed for non-contact temperature sensing. An internal 17-bit ADC and a powerful DSP contribute to the MLX90614's high accuracy and resolution. It has a huge number of applications including body temperature measurment and movement detection.

The MLX90614 provides two methods of output: PWM and SMBus (i.e. TWI, I2C). The 10-bit PWM output provides a resolution of 0.14°C, while the TWI interface has a resolution of 0.02°C. The MLX90614 is factory calibrated in wide temperature ranges: -40 to 85°C for the ambient temperature and -70 to 382.2°C for the object temperature. The measured value is the average temperature of all objects in the Field Of View of the sensor. The MLX90614 offers a standard accuracy of 0.5°C around room temperatures.

This devices comes in an industry standard TO-39 package. We're carrying the 3V version of this sensor.


  • Small size, low cost
  • Easy to integrate
  • Factory calibrated in wide temperature range:

-40 to +85°C for sensor temperature

  • -70 to +380°C for object temperature
  • SMBus compatible digital interface
  • Customizable PWM output for continuous reading
  • High accuracy of 0.5°C over wide temperature range (0 to +50°C for both Ta and To)
  • Measurement resolution of 0.02°C
  • Single and dual zone versions
  • Simple adaptation for 8 to 16V applications
  • Power saving mode
  • Different package options for applications and measurements versatility
  • Automotive grade


Hooking it up

The pins are numbered counter-clockwise from the small pin on the casing while looking at the top of the module.

Pin NumberFunctionDescription
1SCL / VzSerial clock input for 2 wire communications protocol. 5.7V zener is available at this pin for connection of external bipolar transistor to MLX90614A to supply the device from external 8 …16V source.
2PWM / SDADigital input / output. In normal mode the measured object temperature is available at this pin Pulse

Width Modulated.

In SMBus compatible mode automatically configured as open drain NMOS.
3VDDExternal supply voltage.
4VSSGround. The metal can is also connected to this pin.

The Melexis SMBus transfer datasheet shows this as the communication psuedocode:

Pseudo code example: Reading RAM address 0x07 (Tobj1)

  • 1. Send START bit
  • 2. Send Slave Address (0x00* for example) + Rd\-Wr bit**
  • 3. Send Command (0b000x_xxxx + 0b0000_0111 -> 0b0000_0111)
  • 4. Send Repeated START_bit
  • 5. Send Slave Address + Rd\-Wr bit**
  • 6. Read Data Byte Low (master must send ACK bit)
  • 7. Read Data Byte High (master must send ACK bit)
  • 8. Read PEC (master can send ACK or NACK)
  • 9. Send STOP bit

Note* : Any MLX90614 will respond to address 0x00

Note**: Bit Rd\-Wr has no meaning for MLX90614



Modules using this component

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