Audio power amplifiers offer high output power

Raleigh, N.C. — Targeting battery-powered applications, Austriamicrosystems AG's latest single-channel audio amplifiers deliver 1.6-watts of output power.

Austriamicrosystems' AS1701 and AS1706 amplifiers are said to offer higher output power (1.6 W) at comparable distortion levels, or lower distortion levels at comparable output power than similar products. This makes the AS1701 and AS1706 practical for audio front-ends for battery powered audio devices, such as MP3, CD and DVD players, mobile phones, PDAs, portable speakers and other handheld battery-powered devices, the company said.

The AS1701 and AS1706 audio amplifiers contain a bridge-tied load (BTL) output stage to differentially drive 4-ohm and 8-ohm speakers. The amplifiers provide 0.05 percent total harmonic distortion plus noise (THD+N) at 1-W output power into an 8-ohm load. At THD+N of 1 percent, they deliver 1.6-W output power into a 4-ohm load or 1.2 W into an 8-ohm load.

Due to the wide input supply range of 2.7 V to 5.5 V, the amplifiers can be used for 3-V systems as well — delivering 600 milliwatts of continuous output power into 4 ohms. With a low power-supply rejection ratio (PSRR), the AS1701 and AS1706 can be used without a linear regulator even with a noisy digital supply, according to Austriamicrosystems. Gain levels can be adjusted via external components for flexibility.

Austriamicrosystems' integrated shutdown circuitry disables the bias generator and amplifiers, and reduces quiescent current consumption to less than 10 nanoamps. The power down mode can be entered via digital control signal. Click-and-pop suppression circuitry reduces audible clicks and pops during power-up and shutdown.

Related block diagram

The amplifiers are available in an 8-pin MSOP and are said to be pin-compatible with National’s LM4890 and Maxim’s MAX9716. The AS1701 and AS1706 amplifiers are priced at 66 cents each in 1,000-unit quantities. Click here for the AS1701/06 data sheets.

Austriamicrosystems , 1-919-676-5292,

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