Low Voltage, High Gain CMOS Op Amp Using Nested Transconductance Compensation Capacitance

An analytic design guide was formulated for thedesign of 3-stage CMOS OP amp with the nested Gm-C(NGCC)frequency compensation. The proposed design guide generatesstraight-forwardly the design parameters such as the W/L ratioand current of each transistor from the given designspecifications, such as, gain-bandwidth, phase margin, the ratioof compensation capacitance to load capacitance. Theapplications of this design guide to the 10pF load capacitances,shows that the designed OP amp work with a reasonableperformance in both cases, for the range of compensationcapacitance from 10% to 100% of load capacitance.