Audio amplifier eliminates bypass capacitor

National Semiconductor Corporation has announced its release of an audio amplifier that eliminates the bypass capacitor typically connected to the reference voltage pin. The amplifier has a new architecture that improves power supply rejection ratio (PSRR) and provides fast turn-on times, suited for applications in small, portable devices such as mobile phones and notebook computers.

The product's fast turn-on and turn-off times are also very important for power consumption, enabling aggressive power management and longer talk time in cellular applications," says Ken Boyce, marketing director for National Semiconductor's audio products group.

Designed to improve overall system performance, the LM4906 is capable of delivering 1W of continuous average power to an 8½ bridge-tied load (BTL) with less than 1% total harmonic distortion plus noise (THD1N) from a 5V dc power supply. It has an internal selectable gain of either 6 or 12dB and does not require output coupling capacitors or bootstrap capacitors. The LM4906 contains pop and click circuitry that eliminates noise which occur during turn-on and turn-off transitions. It also features a low power consumption shutdown mode and an internal thermal shutdown protection mechanism.The LM4906 is available in LLP chip-scale packaging and MINI SOIC packaging. $0.60 (1000).

National Semiconductor
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www.national.com