Melexis Advances Core Body Temperature Measurement For Smart Wearables

Tessenderlo-Ham, Belgium, 11 November 2026 – Melexis introduces the MLX90636, the world’s smallest contactless temperature sensor delivering medical accuracy, for potential use in wearable digital health devices. Medical accuracy implies it delivers ±0.2°C accuracy* across the human body temperature range in an ultra-compact package. In parallel, as part of its technology roadmap enabled by the MLX90636, Melexis is researching wrist-to-core modeling to track Core Body Temperature (CBT) from wrist-worn sensor inputs.

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Redefining FIR Sensing for Compact Wearables

As health-monitoring wearables move towards deeper health insights, demand has grown for high-precision, non-contact thermal sensing. Surface-Mount Device (SMD) Far Infrared (FIR) thermometry provides significantly truer surface readings than traditional contact thermometers, which remain susceptible to ambient temperature noise and thermal lag. Building on the market success of the MLX90632, the new MLX90636 sets a new benchmark for potential use in miniaturized SMD FIR temperature sensing.

Developing a stable FIR temperature sensor in an ultra-miniature package presents major thermal management challenges. The MLX90636 contributes to accurate measurements while remaining robust against rapid ambient temperature changes and air turbulence.

Key features and technical specifications include:

• Ultra-miniature: Housed in a chip-scale package measuring just 1.8 × 1.8 × 0.75 mm³, designed for use in optimized space-constrained smartwatches, fitness bands, and smart rings
• Factory-calibrated: Delivered with an accuracy of ±0.2°C within the human body temperature range
• Low Power: Features an operating sleep current below 2.5 µA and programmable refresh rates from 0.5 Hz to 32 Hz, for continuous, battery-operated wearable monitoring
• System Integration: Supports dual 2.8 V or 3.3 V supply lines, an I²C interface with a software-definable address pin, integrated post-calibration options, and open-source GitHub driver support

From Enabling Wrist Temperature to Supporting Core Body Temperature (CBT)

Extreme miniaturization and high accuracy provide wearable manufacturers with a solid hardware foundation. However, wrist skin temperature alone does not yield core body temperature, as skin readings are naturally influenced by local blood flow, ambient conditions, and device thermals.

To address this challenge, Melexis is conducting research to explore core body temperature tracking from MLX90636 sensors integrated into wearable digital health devices. To support exploratory feasibility studies, Melexis is finalizing an evaluation kit to assess core body temperature performance. Potential customers are invited to contact us.

“Melexis has been pushing the limits of temperature sensing for many years, and the MLX90636 moves the boundaries forward once again,” said Joris Roels, Marketing Manager at Melexis. “But accurate skin temperature measurement at the wrist is only part of the challenge. By conducting further research related to the application of our latest sensor, we aim to enable core body temperature estimation.

The MLX90636 is available now. For more information, please visit melexis.com/MLX90636 or contact your local Melexis representative.

* As specified in ASTM standard section 5.4, Designation E1965-98 (Re-approved 2009), Standard Specification for Infrared Thermometers for Intermittent Determination of Patient Temperature.