Photonic Detectors: Phototransistors

Phototransistors are photodiode-amplifier combinations integrated within a single silicon chip. The phototransistor can be viewed as a photodiode whose output current is fed into the base of a conventional transistor. These photodiode-amplifier combinations are put together to overcome the major limitation of photodiodes: unity gain. The typical gain of a phototransistor can range from 100 to over 1500.

Many applications demand a greater output than can be generated by a photodiode alone. Even though the signal of a photodiode can be amplified through external circuitry, this is not always cost effective. In such cases, phototransistors provide a lower cost alternative.

Excelitas VVTT9812FH Silicon Phototransistor

VTT9812FH - Si Phototransistor, 0.192mm2

The VTT9812FH is a silicon phototransistor in an infrared-blocking, flat T 1 ¾ end-looking package. This Silicon phototransistor provides an excellent response in the visible spectral range.