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Class AB audio amp delivers fast response

Posted: 13 Nov 2008 ?? ?Print Version ?Bookmark and Share

Keywords:Class AB audio amplifier? noise-free feature? time fast response?


ON Semiconductor has launched the NCP2991 Class AB audio amplifier dedicated to providing superior audio performance without sacrificing power efficiency for portable and wireless applications.

The NCP2991 addresses two of the most crucial requirements in today's portable and wireless audio applications, namely customer demand for noise-free audio amplification and fast response time.

NCP2991 offers a superior power supply rejection ratio of -103dB that eliminates any noise that may be generated by the fluctuation of battery supply voltage. The device is highly resistive to the so-called TDMA noise that occurs during the GSM transmission. Additionally, the device guarantees zero pop-and-click noise at start-up and shut-down, which apply to all input configurations. Its very low typical total harmonic distortion level (0.015 percent) further ensures high fidelity audio output.

The start-up time of NCP2991 is selectable between 15ms and 20ms. Due to its very fast start-up time, the NCP2991 can be kept in shut-down mode when it is not in use. Therefore, most of the time, the NCP2991 consumes only 20nA. Fast audio response is especially crucial for portable devices with touch screen, since the audio feedback is perceived by end-user as the indication of the total system's responsiveness.

In addition, the device is capable of delivering 1.35W of output power to an 8? speaker, or 1.1W to a 4? speaker. It also has built-in thermal overload protection circuitry to disable the device's operation in case of an over-temperature situation.

"Having a clear, noise-free audio output is crucial to the user's satisfaction of a cell phone or portable media device," said Manor Narayanan, VP and general manager of ON Semiconductor's digital and consumer products group. "Hardware designers, however, typically encounter unexpected noise issue coming from the audio system. ON Semiconductor's new Class AB amplifier ensures noise-free amplification and is resistive to external noise sources so it guarantees a high quality audio performance. By enforcing our amplifier's robustness, we expect to minimize the audio designer's effort and design cycle time."

Available in the industrial standard 1.45mm x 1.45mm x 0.6mm ?Bump package and is priced at 22 cents per unit in 3,000 quantities.

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