An Ultra-Low-Voltage, 16-Channel Current DAC ASIC in 22nm FDSOI for cryogenic SQUID Biasing

In this work, we present a sixteen-channel, ultra low-voltage (≤ 0.1 V analog supply) current DAC ASIC designed in 22nm FDSOI technology for biasing SQUIDs. The ASIC integrates eight 6-bit DACs and eight 8-bit DACs, programmed through a simple serial interface. It operates effectively across a wide temperature range, from 300K to 4K, by using the back-gate bias to counteract threshold voltage variations across temperature. The thermometric DACs’ output current range is 0.25 mA and 1.25 mA for the 6-bit and 8-bit DACs, respectively. Measurement results at both cryo and room temperature demonstrate excellent performance, with DNL below 0.5 LSB for the 8-bit DAC and below 0.25 LSB for the 6-bit DAC.

We report on the design and test measurements of ASIC, as well as the status of the integration with Superconducting Low-inductance Undulatory Galvanometers (SLUGs).