BD5424EFS is a 20W + 20W stereo class-D power amplifier IC, developed for space-saving and low heat-generation applications such as low-profile TV sets. The IC employs state-of-the-art Bipolar, CMOS, and DMOS (BCD) process technology that eliminates turn-on resistance in the output power stage and internal loss due to line resistances up to an ultimate level. With this technology, the IC has achieved high efficiency of 91% (10W + 10W output with 8O load), which is the top class inthe industry. The IC, in addition, employs a compact back-surface heat radiation type power package to achieve low power consumption and low heat generation and eliminates necessity of installing an external radiator, up to a total output of 40W.This product satisfies both needs for drastic downsizing, low-profile structures and powerful, high-quality playback of the sound system.