Design and characterization of three stage CMOS op amps in 130nm technology with indirect feedback compensation technique

This paper presents the three stage CMOS operational amplifier (op amp) with class A output stage designed in SilTerra´s 130 nm CMOS technology. The designed three stage op amp employed an indirect feedback compensation technique produces an open loop gain (A_OL), for both schematic and layout are 102 dB and 117 dB respectively. the op amp produces 40.5 MHz gain-bandwidth product (GBW), 90° phase margin(PM) and 54.6 V/μs slew rate (SR) for 5 pF load. Furthermore, the op amp has capability to drive the 15 pF load, produces 25.5 MHz GBW and 45° PM. The circuit was operated at the single supply voltage of 2.5 V with power consumption of 0.977 mW and the layout area was 0.0022 mm².