Santa Clara, Calif. – National Semiconductor Corp.'s latest Boomer audio amplifier eliminates the need for a reference voltage bypass capacitor. The architecture improves the power supply rejection ratio and provides fast turn-on times, National said. Advanced pop-and-click circuitry eliminates noise that would otherwise occur during turn-on and turn-off. The device is aimed at small, portable devices.
The LM4906 can deliver 1 watt of continuous average power to an 8-ohm bridge-tied load with less than 1 percent total harmonic distortion plus noise from a 5-Vdc power supply. Selectable gain is either 6 or 12 dB, and the amp does not require output coupling capacitors or bootstrap capacitors. A low-power shutdown mode and an internal thermal-shutdown protection mechanism are provided.
The LM4906, available now in LLP chip-scale packaging and a mini SOIC package, is priced at 60 cents each in 1,000-unit quantities.
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