Cryogenic Temperature Induced Instability of 200MHz CMOS Operational Amplifier

This work investigates the electrical performance of a high speed general purpose operation amplifier, OPA2356, operating under cryogenic temperature -180oC. 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 -180oC 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 -180oC/24hrs and ~1.8σ 25C-initial at 25oC/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.