Photodiodes can be broken into two categories: large area photodiodes with their attendant high capacitance (30pF to 3000pF) and small area photodiodes with relatively low capacitance (10pF or less). For optimal signal-to-noise performance, a transimpedance amplifier consisting of an inverting operational amplifier 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 operational amplifier input voltage noise, while small area photodiode amplifiers require more attention to reducing operational amplifier input current noise and parasitic capacitances.
Transimpedance Amplifier for Small Area Photodiode
Transimpedance Amplifier for Large Area Photodiode
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