Mismatch insensitive automatic tuning control for the single electron transistor readout circuit

Unavailability of suitable simulation models poses a particularly difficult problem in the field of CMOS analog circuit design for deep cryogenic applications: the performance of the design cannot be verified prior to fabrication. Therefore, the first generation circuits previously reported by the authors for the purpose of reading out Single Electron Transistor (SET) signals-while operating immersed in liquid helium-were equipped with numerous external controls to ensure its proper functionality. In this paper we address the issue of external manual biasing and present a novel approach to achieve self-regulated automatic tuning-one of the most important requirement for future standalone, self-sufficient SET readout circuitry. The proposed scheme is mismatch insensitive, does not compromise the speed and adds very little power overhead to the previous designs.