The VT171P single-channel and VT172U dual-channel transmissive sensors are surface-mount devices designed for position sensing in industrial, consumer and telecom applications. Housed in a 5.5mm × 4mm × 5.7mm package with a 42% increased dome height compared to previous-generation industrial devices. Supports greater mechanical design flexibility and increased vertical clearance for large code wheels in turn-and-push applications. Both devices integrate an infrared emitter with phototransistor detection and operate at a wavelength of 950nm. Deliver a typical output current of 1.5mA with a 3mm gap width, 0.3mm apertures, and rise and fall times of 14ms and 21ms. The VT172U adds dual-channel detection for direction sensing, while both devices support motion and speed detection for encoders, automation systems, consumer electronics, appliances, health and care devices, switches, relays, antennas, and mobile broadband equipment.