Light photons impinging upon a semiconductor material in the vicinity of a P-N junction release conduction carriers to produce current flow through the photodiode effect. Photodiode amplifiers convert this current to a voltage in a relationship that remains linear as long as the amplifier eliminates signal voltage swing from the photodiode. For this purpose, the simple current-to-voltage converter or transimpedance amplifier presents a virtual ground to the diode. However, when connected to a photodiode, this simple op amp circuit displays surprising multidimensional constraints that defy conventional op amp intuition.

Table of Contents

Photodiodes. The Basic Amplifier. Bandwidth and Stability. Wideband Photodiode Amplifiers. Noise. Noise Reduction. High-Gain Photodiode Amplifiers. Reducing Power-Supply Noise Coupling. Reducing External Noise Effects. Position-Sensing Photodiode Amplifiers.