ams Launches Industry’s Smallest Proximity Sensor to Enable Integration of New Functionality in Space-Constrained Wireless Earbuds

By Tiera Oliver

Assistant Editor

Embedded Computing Design

February 16, 2021


ams Launches Industry’s Smallest Proximity Sensor to Enable Integration of New Functionality in Space-Constrained Wireless Earbuds

ams launched the TMD2636, a fully integrated proximity sensor which, according to the company, occupies 30% less space than currently available solutions and delivers transformational added value to manufacturers of True Wireless Stereo (TWS) earbuds. 

Proximity detection performed by one or more TMD2636 sensors enables the earbud to automatically power up when inserted in the ear and power down when removed. This maximizes power savings when the earbud is not in use while providing an ideal user experience. 

The TMD2636 sensor module integrates a 940nm infrared (IR) Vertical-Cavity Surface-Emitting Laser (VCSEL) emitter, IR-sensing photodiodes, sophisticated control circuitry, and a clear-mold overlay in a 2.0mm x 1.0mm x 0.35mm package. The sensor has an average active-mode current consumption of 70µA and 0.7µA in sleep mode. Central are the TMD2636 power-savings benefits, especially in the small battery capacity and size of a wireless earbud product.

The development of the TMD2636 benefited from numerous ams innovations in photodetector technology, optical package design, and factory test and calibration. The design of the TMD2636 provides crosstalk rejection, high immunity to interference from ambient light, and effective algorithms which produce accurate proximity detection results. In addition, the TMD2636 digital I2C interface provides a patented solution for two devices to reside on the same bus, simplifying the system design for dual devices.

Innovations in package miniaturization provide earbud manufacturers new scope to rethink earbud design and to offer an improved user experience. The overall volume of the TMD2636 is 30% smaller than that of earlier products: this offers product designers new freedom to incorporate multiple sensors or to integrate new functionality using components which could not be previously be accommodated. For instance, with multiple TMD2636 sensors, earbud in-ear detection and power management can be made more intelligent.  

The TMD2636 proximity sensor is available for sampling. For more information, visit:


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Tiera Oliver, Assistant Editor for Embedded Computing Design, is responsible for web content edits and constructing stories. She also assists with newsletter updates as well as contributing and editing content for ECD podcasts and the ECD YouTube channel. Before working at ECD, Tiera graduated from Northern Arizona University where she received her B.S. in journalism and political science and worked as a news reporter for the university’s student led newspaper, The Lumberjack.

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