Low noise amplifiers for small and large area photodiodes are discussed.
Low noise amplifier
Photodiodes can be broken into two categories: large area photodiodes with their attendant high capacitance (30pF to 3000pF) and smaller area photodiodes with relatively low capacitance (10pF or less). For optimal signal-to-noise performance, a transimpedance amplifier consisting of an inverting op amp and a feedback resistor is most commonly used to convert the photodiode current into voltage. In low noise amplifier design, large area photodiode amplifiers require more attention to reducing op amp ...