A 1.16-V 5.8-to-13.5-ppm/ ◦C Curvature-Compensated CMOS Bandgap Reference Circuit With a Shared Offset-Cancellation Method for Internal Amplifiers

Abstract

This article introduces an accurate current-mode bandgap reference circuit design with a novel shared offset compensation scheme for its internal amplifiers. This bandgap circuit has been designed to operate over a very wide tem- perature range from −40 ◦C to 150 ◦C. Its output voltage is 1.16 V with a 3.3-V supply voltage. A multi-section curvature compensation method alleviates the error from the bipolar junction transistor’s base–emitter nonlinear voltage dependence on temperature. The bandgap reference circuit contains two operational amplifiers that are utilized to generate proportional- to-absolute-temperature (PTAT)and complementary-to-absolute- temperature (CTAT) current sources. With the implementation of the described shared offset-cancellation methodology, the sim- ulated output inaccuracy introduced by the amplifier is kept to a 5 σ offset within ±4.6 μV while allowing to conserve die size and power consumption by preventing that each amplifier is accompanied by its own active auxiliary offset-cancellation circuit. Designed and fabricated in a 130-nm CMOS process technology, the bandgap reference has a measured output voltage shift of less than 1 mV over a −40 ◦C to 150 ◦C temperature range and an overall variation of ±8.2 mV across seven measured samples without trimming.