A 5.6-100K, 128ppm/K Cryo-CMOS Current Reference

The first CMOS current reference with a measured temperature coefficient across cryogenic temperatures is reported. Implemented in a 14nm FinFET technology, occupying 0.14mm2, and drawing 38uA from a 1.4V supply, the reference uses mutual compensation between a MOSFET gate-source voltage and thin-film resistance—a circuit technique that improves as cryogenic temperatures are approached—to achieve a temperature coefficient of 128ppm/K over 5.6-100K, as averaged over 5 dice from 3 wafers. The cryogenic supply sensitivity, at 0.06%/V, is 6x lower than the lowest reported among cryo-CMOS references, either current or voltage. Finally, cryogenic low-frequency noise is measured for the first time among cryo-CMOS references, either current or voltage.