I am designing a high-bandwidth, broadband (300 MHz- 1GHz) avalanche photodetector with single-ended output for low-impedance loads (~50-100 Ohm). I have two basic options, each of them requires different circuitries, I need help in choosing the right solution:
1. Using APDs with built-in transimpedance amplifier: I have only found diodes with differential outputs. Here, I need no additional gain (altough it would not hurt either), but I do need a circuitry for creating single-ended output from the differential.
2. Using APDs without built-in transimpedance amplifier: here, single-ended outputs are available. Here, I need a circuitry providing at least 500 V/A transimpedance gain that also buffers the diode to be able to drive the low-impedance loads.
Could you recommend proper circuit design for this with proper components? Any recommendations for layout? For me the high bandwidth makes this a rather difficult task. I have looked into many spec sheets for rf amplifiers and op amps, but I am not sure which one to choose, and where it can go wrong. I would really need an expert's opinion.
Many thanks in advance!
Hi kazspore: If the APD has fairly low capacitance, then the LTC6268-10 can be used in applications up to about 400MHz.
We also have dedicated TIA's such as HMC799, with a 1GHz data rate, but the gain is 10k Ohms.
Oh, and to answer Q1, I would use AD8099 in a 4-resistor difference application.