MLX90614 IR thermometer: specs and pinout
The MLX90614 is a factory-calibrated infrared thermometer in a TO39 can with SMBus and PWM output. It measures object and ambient temperature.
Specs
| Spec | Value | Source |
|---|---|---|
| Supply voltage, 5 V option (Axx types) | 4.5 V to 5.5 V (5.0 V typ) | source Electrical specifications, 5 V devices, p.8 |
| Supply voltage, 3 V option (Bxx types) | 2.6 V to 3.6 V (3.0 V typ) | source Electrical specifications, 3 V devices, p.9 |
| Supply current | 1.3 mA typ, 2.5 mA max | source Electrical specifications, p.8-9 |
| Object temperature range | -70 C to +380 C | source Features, p.1 |
| Sensor (ambient) temperature range | -40 C to +125 C | source Features, p.1 |
| Accuracy (standard version) | 0.5 C over 0 C to +50 C for both ambient and object temperature | source Features, p.1 |
| Measurement resolution | 0.02 C | source Features, p.1 |
| Interface | SMBus (default at power-on) and 10-bit PWM | source Description, p.1 |
| Default SMBus slave address | 0x5A | source SMBus command figures, p.20 |
| Operating ambient temperature | ESF types -40 C to 85 C; KSF types -40 C to 125 C | source Absolute maximum ratings, p.7 |
Power
| Value | Source | |
|---|---|---|
| Supply | 3 V (Bxx) or 5 V (Axx) chip type, see specs; the listing does not say which and the module supply is not documented | source Electrical specifications, p.8-9 |
| Current | 1.3 mA typ, 2.5 mA max | source Electrical specifications, p.8-9 |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently.
Pins are those of the bare TO39 chip (bottom view). The module board's regulator, pull-ups and header order are not covered by an official document.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| 1 SCL / Vz | SMBus serial clock (5.7 V zener on Axx versions) | Input | source Section 2 Pins description, p.6 | |
| 2 SDA / PWM | SMBus serial data / PWM output | I/O | source Section 2 Pins description, p.6 | |
| 3 VDD | External supply | Supply | source Section 2 Pins description, p.6 | |
| 4 VSS | Negative supply (ground) | 0 V | Supply | source Section 2 Pins description, p.6 |
Build with it
Project ideas for the MLX90614 IR thermometer. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Object temperature display: The stocked module's supply voltage (3 V or 5 V chip type) and level handling are not documented, so this page cannot say how to wire it to the ESP32's 3.3 V I2C lines: check the chip marking and the module before connecting. Shows object and ambient temperature. Not a medical thermometer.
- Serial temperature logger: The stocked module's supply voltage is not documented, so this page cannot confirm it runs from the Uno's 5 V: check the chip marking (3 V or 5 V type) and the module before connecting. Readings are sent to the serial monitor for logging. Learning project.
- Ambient and object temperature on an LCD: The stocked module's supply voltage is not documented, so this page cannot confirm it runs from the Uno's 5 V: check the chip marking (3 V or 5 V type) and the module before connecting. The chip reports both ambient and object temperature. Learning project.
Common mistakes
- Powering a 3 V (Bxx) chip from 5 V: the Bxx absolute maximum supply is 5 V for under 24 hours and the supply range is 2.6-3.6 V (source: link, Table 3 p.7 and Table 6 p.9)
- Using the wrong supply for the ordered type: the 5 V (Axx) type needs 4.5-5.5 V (source: link, Table 4, p.8)
- Connecting the metal can to anything other than VSS: the sheet recommends no electrical connection to the metal can (source: link, Section 2 pin description after Table 2, p.6)
Not covered by the official source
- Listing does not say whether the module carries a 3 V or 5 V chip, nor its field of view; only variant-independent facts are given.
- Chip datasheet only; the module board is undocumented.
- Supply ranges are from the 5 V and 3 V tables of the Melexis datasheet; current is from both tables and the page-1 feature list.
Sources
- link (Melexis MLX90614 datasheet Rev 021, 02-Jun-2026)