Efficient four-stage frequency compensation for low-voltage amplifiers

This paper proposes a simple and efficient frequency compensation scheme, targeted at low-voltage amplifiers. An amplifier is correspondingly designed in 0.12-mum standard digital CMOS technology. When the supply voltage is IV and the load is 500 pF, post-layout simulation results show that the amplifier attains a gain-bandwidth product of 40.2 MHz, an average slew-rate of 17.52 V/mus and a current consumption of 1.4 mA. The stability of the amplifier is confirmed by sufficient phase margin and fast settling behavior. The efficiency of the proposed compensation approach is also highlighted by a comparison of figures of merit (FOM) with recent designs. In addition, four new FOMs are developed to evaluate the compensation efficiency in a more accurate manner.