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

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 temperature range from -40 degrees C to 150 degrees 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-absolutetemperature (CTAT) current sources. With the implementation of the described shared offset-cancellation methodology, the simulated output inaccuracy introduced by the amplifier is kept to a 5 sigma offset within +/- 4.6 mu V 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 degrees C to 150 degrees C temperature range and an overall variation of +/- 8.2 mV across seven measured samples without trimming.

Automated summary

This article introduces an accurate current-mode bandgap reference circuit design with a novel shared offset compensation scheme for its internal amplifiers. The circuit is designed to operate over a wide temperature range and effectively reduces output inaccuracy introduced by the amplifier through the shared offset-cancellation methodology.