Based upon a half bridge topology, the IRS2093 from International Rectifier integrates four channels of Class D audio amplifier drivers with PWM modulators in a single IC. Features of the MLPQ48-packaged 200-V device include an error amplifier, PWM comparator, gate driver, an analog PWM modulator with frequency up to 800 kHz, and programmable bidirectional over-current protection with self-reset control, under-voltage lockout, and programmable preset deadtime. The part is optimized around parameters critical to audio performance such as efficiency, THD, and EMI. From $10.80 in 10,000-unit quantities.
310-726-8512, www.irf.com 
A datasheet and application note on the IRS2093 are available on the website at http://www.irf.com .