A 60 mW Class-G Stereo Headphone Driver for Portable Battery-Powered Devices

A 60 mW 1.15 mA/channel Class-G stereo headphone driver primarily designed for demanding applications in mobile phones and other portable communication devices is described. The architecture of the driver has been chosen to overcome the various design challenges for audio amplifiers in a wireless environment. A high-order feed-forward loop topology provides high immunity to battery disturbance with extended correction range. In addition, a Class-G amplifier with a Class-AB/B driving stage improves the small-signal efficiency and extends music playback time. Implemented in 0.18 μm CMOS technology, the stereo headphone driver achieves a DR of 111 dB and PSRR of 120 dB at the GSM TDMA frequency of 217 Hz while occupying an area of 2.3 mm
²
.