I have problem with Opamp transient simulation. I´ve designed several one stage structures (folded, telescopic, symetrical CMOS) and all made same problem. In attachment file is simulation connection - R ratio is 1. So If I have input sinus amplitude 1 V, output amplitude is not 1 V but a little bit smaller. I don´t know, where is mistake. It is only in one stage structures, two stage is ok. Could somebody help me?
The gain of an opamp with feedback always is slightly smaller than indicated by the R ratio - depending on the opamp open loop gain.
Don't you know Blacks classical formula for feedback?
Firstly, thank you for your answer...Yes I know it. But gain of this opamps is sufficiently (approx. 75 dB). When I give ideal VCVS (gain = 1) to output, it is ok. Maybe output current make this worst, but its small enought.....