A Cryo-CMOS Voltage Reference for Quantum Computing Applications

Abstract

Voltage references are an essential building block for many electronic systems, such as analog-to-digital and digital-to-analog converters, and voltage regulators. Although state-of-the-art voltage references already demonstrated high performance over the standard temperature range (−40 °C to 125 °C), specific applications require an operating temperature far beyond this range. A relevant example is the electronic interface for quantum processors, for which voltage references that can operate down to cryogenic temperatures are needed. This thesis presents a CMOS-based voltage reference that can work over a wide temperature range from 4K to 300K. To achieve a low-drift, high-accuracy reference, it is designed based on the devices’ cryogenic behaviour to minimize the nonlinearities of the PTAT- (proportional to absolute temperature) and CTAT (complementary to absolute temperature) voltages and combine them to generate a stable output voltage. Dynamic compensation techniques are employed to reduce the effect of process variations and a switched-capacitor circuit is proposed to minimize the output ripple. The targeted specifications of this design are comparable with the state-of-the-art voltage references working at room temperature. To verify the performance at cryogenic temperatures, the design has been taped out in 40nm CMOS technology.