Low-cost, high switching frequency help Class D audio amplifiers reach broader markets

Texas Instruments (Dallas) expanded its Class D audio amplifier line with three pin-compatible products that yield lower BOM costs, a wide power supply range, and high switching frequency.

The stereo amplifiers are expected to "open the market for Class D products," according to Josey Angili, home audio marketing manager at TI. Higher efficiency levels and lower BOM costs will make the Class D devices more accessible to cost-sensitive applications, including the LCD TV market, soundbars, after-market automotive solutions and portable audio docks, Angili added.

With a supply range of 4.5 V to 26 V, the TPA3116D2, TPA3118D2 and TPA3130D2 are closed loop amplifiers that support a single-layer printed circuit board (PCB) design, helping to reduce costs since designers can use a single layout for multiple designs. 

Additional cost reductions are realized by providing what TI claims is the highest programmable switching rates up to 1.2 MHz, eliminating the need for inductor filters. Previously, in 15 W x 2 or 30 W x 2 high-switching applications such as in IPod docking systems, designers used 4x 15 µH inductors to filter the two channels. The TPA3116D2, TPA3118D2 and TPA3130D2 require ferrite beads, which cost less than 2 cents each vs. approximately 10 cents each for the inductors. Also, thermally efficient FETs allow 30-W x 2 operation without the need for a heat sink.

TI raised the peak current capability to 7.5 amps, which will help boost audio quality by allowing systems to play through music peaks without current limiting. Additional enhancements include the RDS(on) of 120 milliohms at 30-W x 2, which is 20-percent lower than the leading competition, according to TI. This helps improve efficiency by decreasing resistance during operation.

TI is working on a home audio chipset with advanced digital processing technology that can drive much higher power performance, Angili said. These smart amplifiers will be targeted at small speakers designed into notebooks and all-in-one applications, he added. Samples are expected to be ready in July of this year.

The TPA3116D2, TPA3118D2 and TPA3130D2 are available now in a 10-mm x 6-mm 32-pin HTSSOP package, priced at $1.80 for the TPA3116D2, $1.65 for the TPA3118D2, and $1.30 for the TPA3130D2, each in quantities of 1,000.

Datasheets: Click here.