TSSP4056 Fast Proximity Sensor

Vishay’s infrared (IR) sensor is designed to provide fast, low-cost proximity sensing in a variety of systems. The Vishay Semiconductors' TSSP4056 is the industry’s first fixed-gain sensor containing a band-pass filter tuned to 56 kHz to feature a monotonic sensitivity versus frequency response curve from 30 kHz to 54 kHz. The device detects modulated pulses from a separate IR emitter with a high sensitivity of 0.4 mW/m2, while fast readings in under 5 ms are possible using successive approximation techniques, as demonstrated in Vishay’s Fast Proximity Sensor software.

• >4x dynamic range from lowest to highest sensitivity
• Features a PIN photodiode and sensor IC in a single package to simplify designs
• Designed to receive IR pulses from an emitter with a peak wavelength of 940 nm

Typically, proximity sensors determine an object’s distance by varying the emitter’s drive current to find the threshold emitter power at which the object is just detected, a technique that requires an expensive DAC to drive the emitter. The TSSP4056, however, determines distance by varying the carrier frequency used to drive the emitter between 30 kHz and 54 kHz, thereby finding the threshold frequency at which the sensor just detects the object. This approach does not require the microcontroller to contain a DAC, thus lowering overall solution costs.