MASH Digital Delta-Sigma Modulators for the CMOS Qubit Controller

A reliable and highly linear operation of integrated cryogenic CMOS circuits is essential for controlling multiple qubits without degrading quantum functionality. This paper presents a CMOS qubit controller based on a delta-sigma modulator (DSM) with reduced control bits. The behavioral model with different multi-stage noise shaping (MASH) DSM is also compared to the conventional Nyquist-mode operation. The total power dissipation of the proposed qubit controller is 1447 mW (digital: 1313 mW, analog: 134 mW). The prototype is fabricated in a $28-\mathrm{nm}$ CMOS process with a total area of 4 $\mathbf{m m}^{2}$.