A highly accurate BiCMOS cascode current mirror for wide output voltage range

Abstract

In this paper, a highly accurate wide swing BiCMOS cascode current mirror is proposed. It uses the base-current compensated BJT current mirror. It increases both output impedance and output voltage range by using the npn-NMOS cascode instead of the NMOS-NMOS cascode. The npn transistor copies the input current and the NMOS transistor increases the output impedance for the accurate current mirroring. The proposed current mirror achieves highly constant current for wide output voltage range. Simulation results were verified with measurements performed on a fabricated chip using a 5/16 V 0.5 um BCD process. It has only -2.5~1.0% current error for 0.3~16 V output voltage range.