Cryogenic Temperature Induced Instability of 200MHz CMOS Operational Amplifier

Abstract

This work investigates the electrical performance of a high speed general purpose operation amplifier, OPA2356, operating under cryogenic temperature -180°C. Evidence of cryogenic-induced instability of OPA2356 was experimentally observed and repeated using different hardware setups — a subtle increase in OPA2356's Isupply current variations after extended -180°C cold dwell for 24 hours. The monitored Isupply current revealed increased random fluctuation of Isupply, characterized by its standard deviation σ, as compared to its initial room temperature current (σ25C-initial). This is exemplified by ~2σ 25C-initial at −180°C/24hrs and ~1.8σ 25C-initial at 25°C/post-cold. This work also suggests using the static supply current (Isupply), also commonly known as DC quiescent current, of the analog chip as a good monitor of analog chip's instability operating under cryogenic conditions. This is demonstrated using another hardware setup where the OPA2356 was implemented as a unity-gain amplifier. We also found that increasing voltage headroom by maximizing the allowable VDD in analog chips will enable proper cryogenic operation of analog chips, which can be a critical trade-off for a space electronic system to consider between long term reliability and operating window.