A Sub-1-V 8.5-ppm/°C Sampled Bandgap Voltage Reference

This brief proposes a novel sub-1V discrete-time CMOS bandgap reference circuit where a constant voltage is produced by summation of a CTAT and a PTAT voltage that are sampled onto a capacitor. By sampling the voltages onto a capacitor, we eliminate the need for an opamp in the bandgap core, which tends to be the dominant source of noise and offset concerns in low voltage bandgap designs in scaled technologies. A prototype was designed and fabricated in 28nm TSMC HPC+ technology with a nominal output voltage of 108mV. It demonstrates a temperature coefficient of 8.5ppm/°C between −40°C and 125°C, and occupies an area of 0.0075mm2 while consuming $11.6\mu \text{W}$ of power.