Class-D amplifiers revolutionize small-system designs

Thanks to architectural and process advances in Class-D audio power amplifiers (APAs), the day is quickly approaching when the sound systems of handheld devices will rival those of today’s oversized, cumber-some boom boxes.

Texas Instruments is helping to drive that change with the introduction of a new Class-D device that will allow designers of portable electronic systems to reduce power consumption, system size and cost. Because the new device, the TPA005D02, is more power-efficient than the older Class-AB APAs, it will extend the battery life and reduce the size and cost of power supplies in portable systems such as handheld PCs, personal digital assistants, wireless telephones, portable music systems and others.

The device, capable of driving stereo speakers at 2 W continuously with 5-W peaks, is the first in TI’s new family of Class-D APAs, and it’s the first in the industry to integrate the control circuitry and stereo output stage on a single monolithic die. Until now, linear Class-AB audio amplifiers have been used in most portable systems, but advances in the sound quality of Class-D APAs and their power-efficiency advantages over Class-AB APAs is causing a shift toward Class-D devices. Class-D APAs feature a different, more efficient architecture than Class-AB. Unlike Class-AB devices, which typically waste more than 75 percent of their input power as heat, Class-D APAs dissipate as little as 20 percent of their input power. With power-efficiency over 80 percent or three times that of Class-AB amplifiers, Class-D APAs generate significantly less heat, which simplifies system assemblies and improves reliability.

To help designers implement Class-D audio power amplifiers, TI has developed an evaluation module fully compatible with its APA Plug ’n Play Platform, the only one of its kind in the industry. To help maximize sound quality, a comprehensive application note on low-pass filtering will be available later. Full documentation for the TPA005D02 includes a user’s guide with reference designs and schematics. Gerber files are available upon request.

The device is available now from TI and authorized distributors.

Suggested resale pricing in U.S. dollars in 1K quantity.

* PowerPAD™ package

PowerPAD is a trademark of Texas Instruments.

For complete information, order: Data Sheet (SLOS227A), User’s Guide (SLOU032) and Class-D Amplifiers Technical Brief (SLOT130). See Related Product Information.