Unlike traditional amplifiers, the common source output stage of the rail-to-rail I/O amplifier has gain and bandwidth more sensitive to resistive a capacitive loading. The bandwidth variation along with the input capacitance significantly impacts amplifier stability. This paper has presented circuit designs of a rail-to-rail input and output CMOS amplifier with 3 possible solutions to the challenge of reducing amplifier instability have been discussed 1. Feedback resistor value reduction to minimize the impact of Cin. 2. Introduction of a Ccomp in parallel with RF. 3. An Increase of closed loop gain.
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