A 1MW -101DB THD+N Class-AB High-Fidelity Headphone Driver in 65NM CMOS

Abstract

This paper presents a class-AB driver for high-fidelity audio. It attains high-linearity at low-power by using an improved output stage biasing technique and a new frequency compensation scheme. Designed in standard 65nm CMOS, the driver delivers 5I.2mW peak power to 16Ω 0.33nF load, while consuming 0.97mW. It achieves -101.4dB THD+N over full audio band, the lowest ever reported linearity among sub-milliwatt CMOS class-AB drivers. Compared to prior works, it has >12dB better linearity and >7x higher unity-gain bandwidth, resulting in 2.5x improvement in linearity FOM (=Peak Load Power/ (Quiescent Power × THD+N[%])).