Article ID: 2024CTP0001
A cryogenic analog controller (CAC) for a silicon quantum computer using a spin qubit is presented in this paper, which operates on 4-K plate in a dilution refrigerator to suppress heat flow to qubits and latency. An RF pulse generator is a key for precise control of a spin qubit in CAC, which is required to generate 20-GHz pulse with low phase error. A low-noise LO and calibrations for DC offset and IQ imbalance are implemented in the pulse generator. LO includes LDO operating at weak inversion region and transformer coupled VCO cores to suppress flicker noise. A BGR operating at weak inversion region is also applied to supply low-noise bias voltage. CAC including the pulse generator is fabricated in 40-nm CMOS process. Low LO jitter of 137.4 fs, -59.7-dBc LO leakage, 67.7-dB IRR and 388-nJ energy per quantum operation have been achieved with the proposed 20-GHz LO and calibrations, resulting in 99.93-% fidelity.
