by AntalGrobinal » Sun Jan 22, 2023 10:54 pm
I'm designing a circuit to count pulses received by an INGAAS photodiode. The pulses are 25ns lenght and about 1mJ energy at emitted. It is basically a professional (1500nm) laser range finder with some extra pulse encoding, pointed directly at a photodiode over a few km. e.g. not detecting reflections but direct emissions.
Designing the circuit was quite straight forward using an LTC6229 high speed op-amp and the formulas from the data sheet.
I am expecting around 1mA max output from the photodiode at the distance we are working. My simulations in ltspice are all like one expects from the data sheet formulas, and by giving the TIA output into comparator and monstable multi vibrator I can make the short pulses suitable to be read by a microcontroller.