coxstreet
Junior Member level 3
Dear all, I am designing a TIA by using OPAMP whose bandwidth is 100MHz and gain is 100dB and shunt resistor feedback topology in TSMC 035 process.
I firstly design a OPAMP (one stage folded-cascode )with bandwidth and DC gain are 100MHz and 100dB respectively. But when I add a shunt resistor, eg 10K ohms, the TIA still has the gain of 80dB but the OPAMP has some transistors going to linear region.
I guess the explanation is even some are in linear but still the gain of OPAMP is relatively large such that the gain of TIA, Rf, will not be affected.
So my question is how to settle the linear transistors to saturation. Thanks!
I firstly design a OPAMP (one stage folded-cascode )with bandwidth and DC gain are 100MHz and 100dB respectively. But when I add a shunt resistor, eg 10K ohms, the TIA still has the gain of 80dB but the OPAMP has some transistors going to linear region.
I guess the explanation is even some are in linear but still the gain of OPAMP is relatively large such that the gain of TIA, Rf, will not be affected.
So my question is how to settle the linear transistors to saturation. Thanks!