Design of Three-Stage Class-AB 16 Ω Headphone Driver Capable of Handling Wide Range of Load Capacitance

In this paper, the effect of load capacitance variation on the location of the closed loop poles of three-stage amplifiers is analyzed and a frequency compensation scheme that automatically adjusts the damping factor according to the load capacitance is proposed. A class-AB 16 Omega headphone driver designed using the proposed scheme in 0.13 mu m technology can handle 1 pF to 22 nF capacitive load while consuming as low as 1.2 mW of quiescent power. It can deliver a peak power of 40 mW (1.6 Vpp swing) to the load with -84.8 dB THD and 92 dB peak SNR. It occupies 0.1 mm(2) area.