A 0:5V rail-to-rail 1.5 μW CMOS amplifier for micro-energy harvesting applications

This paper presents a fully differential and single ended amplifier design in a standard 0.35 mum CMOS twin well process, targeted to ultra low voltage applications down to 0.5 V. By utilizing bulk-driven PMOS transistors as an input-differential pair a rail-to-rail input common mode range (ICMR) is achieved. Novel CMFB structures in combination with a new amplifier topology allow to achieve high open-loop DC gain of 90 dB and robustness against process and temperature. Moreover, nearly constant performance can be guaranteed over a supply range of 0.5V les V_DD les 3.6V. Furthermore, in a 10 pF load a gain-bandwidth (GBW) of 100 kHz with 60 deg phase margin is obtained for a total power consumption of only 1.5 muW at 0.5V.