Bessel‐like compensation of three‐stage operational transconductance amplifiers

In this paper, we introduce a simple and well‐defined approach for the design of fast settling amplifiers suitable for switched‐capacitor circuits and characterized by low capacitive loads, in the order of few pico‐farad. In the specific, the design is based on a new Bessel‐like compensation that sets the phase of the closed‐loop amplifier to be linearly related to the frequency, thus emulating the behavior of an ideal delay, like in a Bessel filter. The proposed Bessel‐like approach is validated through the design and the simulation of two 3‐stage amplifiers in a 65‐nm CMOS process.