A curvature-corrected CMOS bandgap reference

Abstract

This paper presents a CMOS bandgap reference that employs a curvature correction technique for compensating the nonlinear voltage temperature dependence of a diode connected BJT. The proposed circuit cancels the first and the second order terms in the VBE(T ) expansion by using the current of an autopolarizedWidlar source and a small correction current generated by a MOSFET biased in weak inversion. The voltage reference has been fabricated in a 0.35µm 3Metal/2Poly CMOS technology and the chip area is approximately 70µm × 110µm. The measured temperature coefficient is about 10.5 ppm/K over a temperature range of 10– 90°C while the power consumption is less than 1.4mW.