Sub-ppm/°C High Performance Voltage Reference

A strategy for designing a high accuracy voltage reference operating at sub 1ppm/°C over a wide temperature range is introduced. The proposed design makes use of one of the popular and widely used bandgap voltage reference structures and the temperature dependence of the drain current of a single MOS transistor operating in subthreshold to build a sub-ppm/°C voltage reference. The effects of error sources which may affect the performance of the voltage reference are analyzed and minimized. Simulation results in the TSMC 180nm process show that the design can achieve temperature coefficients of less than 0.85ppm/°C across process corners and local random variations from −40°C to 125°C after trimming.