A Methodology for the Study of Frequency Response of the Active-Cascode Amplifier

This paper presents a methodology to study the frequency response of the active-cascode amplifier semi-quantitatively. It leverages on the sketching of asymptotic Bode plots to obtain the amplitudes and transition points of critical performance functions in the frequency domain. The plots provide helpful insights for guiding the process of manipulating device and system parameters to meet the ever-demanding design specifications, without complicated and sometimes intractable mathematical derivations. Reasonable accuracy of this methodology is justified by comparing the LTSpice simulation results with those obtained by this method, and considering the much less efforts involved herein. The usage of this methodology is also demonstrated by guiding the design process of frequency compensation.