0.85 mW, 8-bit, 1GS/s, 58dB SFDR Cryogenic DAC for Superconducting Qubit Control Applications

This work reports a 8-bit cryogenic digital-to-analog converter (DAC) for qubit control applications. To mitigate the excessive process variations of transistor at cryogenic temperature, we propose a capacitive DAC (CDAC) to utilize the temperature-invariant and better matching properties of MOM-cap devices. Our simulation results showed that SFDR of the CDAC only drops by 1.9dB (from 59.9dBc at 300K to 58dBc at 4K) which is much smaller than 8.5dB change for current steering DAC. This suggests that our proposed CDAC is a promising candidate for cryogenic qubit control applications.