The MLX90614 Non-Contact IR Temperature Sensor is useful solution that combines infrared thermopile sensing with advanced digital signal processing to deliver precise, contactless temperature readings. This article will discuss the MLX90614 temperature sensor in detail, including its pinout, specifications, features, functional operation, application circuits, and more.

Catalog

MLX90614 Temperature Sensor Basic

The MLX90614 Non-Contact IR temperature sensor from Melexis is a digital infrared thermometer. It is designed to measure temperature without physical contact. It works by detecting infrared radiation emitted by an object and converting it into an accurate temperature reading. Because no contact is required, it is ideal for hot, moving, or hard-to-reach surfaces.

Inside the MLX90614 is a thermopile sensor combined with a signal-processing chip. This allows it to measure both object temperature and ambient temperature with high resolution. The sensor is factory-calibrated and provides digital output through I²C/SMBus or PWM, making it easy to connect to Arduino, Raspberry Pi, and other microcontrollers.

If you are interested in purchasing the MLX90614, feel free to contact us for pricing and availability.

MLX90614 Sensor CAD Models

MLX90614 Sensor Pinout Details

Alternatives & Equivalent Model

• Melexis MLX90615

• Melexis MLX90632

• Melexis MLX90640

• Texas Instruments TMP006

• Texas Instruments TMP007

• Panasonic AMG8833

• Omron D6T Series

• Excelitas Technologies ZTP-115

• Excelitas Technologies TPiS 1S 1385

MLX90614 Sensor Functional Diagram

The MLX90614 sensor measures temperature without contact and converts it into a usable digital signal. At the front end of the diagram is the infrared thermopile sensing element, which detects infrared radiation emitted by an object. This radiation is proportional to the object’s surface temperature. At the same time, an internal temperature sensor measures the ambient temperature of the sensor itself, which is important for compensation and accuracy.

The small analog signals generated by the thermopile are routed through a multiplexer and then amplified by an operational amplifier (OPA). This stage conditions the signal so it can be accurately processed. After amplification, the signal enters the ADC (Analog-to-Digital Converter), where the analog temperature information is converted into high-resolution digital data.

Once digitized, the data is processed by the internal DSP (Digital Signal Processor). The DSP applies calibration coefficients stored in memory and performs mathematical compensation using both object and ambient temperature data. This is what allows the MLX90614 to deliver precise, factory-calibrated temperature readings without external calibration.

The processed temperature data can then be sent out through two paths: a digital SMBus/I²C interface or a PWM output for continuous reading. A built-in state machine controls the timing, power modes, and data flow between blocks, while the voltage regulator ensures stable internal operation across different supply voltages. Together, these blocks explain how the MLX90614 reliably converts infrared energy into accurate digital temperature values.

MLX90614 Sensor Specifications

MLX90614 Sensor Features

Small Size, Low Cost

The MLX90614 is compact and lightweight, making it easy to fit into small devices and portable projects. Its affordable cost allows it to be used in consumer electronics, DIY projects, and large-scale production without significantly increasing overall system cost.

Easy to Integrate

This sensor is designed for simple hardware and software integration. With digital output and minimal external components required, it works smoothly with microcontrollers such as Arduino, Raspberry Pi, and other embedded systems.

Factory Calibrated Wide Temperature Range

The sensor is factory calibrated to measure ambient temperatures from –40 °C to 125 °C and object temperatures from –70 °C to 380 °C. This eliminates the need for user calibration and ensures reliable readings right out of the box.

High Accuracy Over a Wide Range

The MLX90614 offers typical accuracy of ±0.5 °C across a broad temperature range. This makes it suitable for applications where stable and consistent temperature measurement is important.

Medical-Grade Accuracy Option

Some variants support enhanced calibration for medical-grade accuracy. This allows the sensor to be used in applications such as body temperature monitoring and healthcare devices.

High Measurement Resolution

With a digital resolution of 0.02 °C, the sensor can detect very small temperature changes. This is especially useful in precision monitoring and control systems.

Single and Dual-Zone Versions

The MLX90614 is available in single-zone and dual-zone models. Dual-zone versions can measure temperature at two different points, improving spatial temperature sensing.

SMBus / I²C Digital Interface

The sensor supports SMBus-compatible I²C communication, enabling stable and noise-resistant digital data transfer with minimal wiring.

Customizable PWM Output

In addition to digital communication, the sensor provides a configurable PWM output. This allows continuous temperature reading without complex digital processing.

3 V and 5 V Versions

The MLX90614 is available in both 3 V and 5 V versions, making it compatible with a wide range of logic levels and power systems.

Simple Adaptation for 8–16 V Systems

With basic external circuitry, the sensor can be adapted for higher-voltage systems, increasing its flexibility in industrial and automotive designs.

Power-Saving Mode

A built-in low-power mode reduces current consumption, making the sensor ideal for battery-powered and energy-efficient applications.

Multiple Package Options

Different package options allow designers to choose the best form factor for their application, improving mechanical and thermal design flexibility.

Automotive-Grade Reliability

Manufactured by Melexis, the MLX90614 meets automotive-grade standards, ensuring long-term stability, durability, and performance in demanding environments.

Typical Application Schematics

MLX90614 Sensor Application Circuit

The MLX90614 sensor application circuit with a 3.3 V SMBus power supply illustrates a typical single-sensor connection to a microcontroller. The MLX90614 is powered from a 3.3 V supply through its Vdd pin, while a 0.1 µF decoupling capacitor (C1) is placed close to the sensor to filter noise and stabilize the supply voltage. The SDA and SCL pins are connected to the microcontroller’s SMBus/I²C lines, allowing digital temperature data to be exchanged reliably. Pull-up resistors (R1 and R2) are required on the SDA and SCL lines because SMBus/I²C uses open-drain signaling. These resistors ensure that the bus lines return to a logic high level when no device is actively pulling them low.

The diagram also shows that the MLX90614 supports both SMBus digital communication and an optional PWM output. When SMBus is used, temperature values are read digitally by the MCU, which simplifies software processing and improves noise immunity. The common ground connection between the sensor and the microcontroller ensures accurate signal referencing and stable communication.

The SMBus configuration for multiple sensors demonstrates how more than one MLX90614 can share the same SDA and SCL bus lines. In this setup, all sensors are powered from the same supply, each with its own local decoupling capacitor to reduce interference. The bus pull-ups can be implemented using resistors or controlled current sources, which help maintain proper logic levels even with multiple devices connected.

Additional bus capacitance (Cbuss1 and Cbuss2) is shown to represent wiring and input capacitance when several sensors are used. Proper pull-up sizing and capacitance control are important to maintain signal integrity and reliable communication. By assigning different SMBus addresses or managing access through software, multiple MLX90614 sensors can operate on the same bus, making this configuration suitable for multi-point temperature monitoring systems.