Tiny digital IR proximity sensing module targets wireless earbuds

By Gina Roos, editor-in-chief

Enabling audio manufacturers of true wireless stereo earbud products to develop smaller and lighter designs, ams delivers the smallest digital proximity sensor module, which occupies only 1 mm³ of volume. This is more than six times smaller than the previous 2-in-1 proximity sensor module.

Ams said the proximity detection performance of the TMD2635 is comparable to that of earlier, larger modules used by the leading smartphone manufacturers, but in a much smaller form factor for wearable devices.

The IR proximity sensors provides in-and-out-of-ear detection to help extend battery life between charging, and can be used in tandem with another TMD2635 to enable elementary touchless gesture control. For additional power savings, the device has an average active-mode current consumption of 70 µA and 0.7 µA in sleep mode.

The TMD2635 module is a complete light-to-digital sensor module that integrates a low-power infrared VCSEL (Vertical Cavity Surface Emitting Laser) emitter, two sensor pixels for near- and far-field sensing, and a digital fast-mode I₂ C interface, in a miniature land grid array (LGA) package.

“And because of the split near-far field photodiode offset emitter to detector positioning, designers of wireless earbuds and other wearable and portable devices have the freedom to optimize both the size and shape of the needed sensor apertures in their industrial designs and optimize their products for comfort and performance — either a 1.5-mm circular or a 1 × 2-mm oval aperture,” said Dave Moon, senior product marketing manager in the Integrated Optical Sensors business line, ams.

The TMD2635 is available in production volume. Unit pricing is $0.89 in quantities of 1,000.