TIA
1. what is the ideal input impedance and output impedance of such circuit?
2. as I recalled, classical TIA has a resistive feedback to boost BW, but reduces Gain. If I designed a TIA using RGC structure without resistive feedback, would there be a problem? (like oscillations or unstable gain?)
3. How to measure 'Sensitivity (dBm) of TIA using HSPICE or Cadence?
4. How to measure 'input referred noise' of TIA using HSPICE or Cadence?
Photodiode
1. can anyone give me a example of practical photodiode model/schematics in the current industry?
2. what is the typical photodiode capacitance (Cpd) for 3.2Gbps applications nowadays? 0.6pF? 1pF?
3. what is the typical dark current (when photodiode is not receiving any data)? 1nA? 5uA? 15uA?
~ :!: any diagrams or sample datasheet would be very helpful...
2. Shunt feedback configuration with resistor Rf is a good compromise between bandwidth, and noise.
As you know it is good to have higher Rf as you can, than you have higher TIA gain, but this is limited to amplifier GainBandwidth product, which is technology dependant.
Instead of Rf it is better if you use NMOS in triode region (much smaller parasitic capacitance).
4. I thinh it should be Vnoise rms at the output divided by TIA gain @0 Hz.
There is a famous book Photodiode Amplifiers by Jerald Graeme that covers this topic. The Burr Brown web site has application notes derived from chapters of this book.
Other good links to information about photodiode and amplification circuits can be found at **broken link removed**
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