Audio amp circuitry suppresses RF signals

Santa Clara, Calif. — National Semiconductor Corp. today introduced an audio amplifier featuring internal circuitry that suppresses RF signals from passing through the amplifier.

The amplifier is designed to suppress strong RF signals and produce clean sound in notebook computers enabled with WiFi/802.11, GSM cards or modems. The device also suppresses RF noise generated by cell phones or other wireless devices operating in close proximity to the notebook computer.

“National's device provides up to a 28 dB improvement in RF suppression over previous designs on the market,” said Mike Polacek, vice president of National Semiconductor's Audio group. Reducing RF issues will shorten design time and ensure high-quality audio performance for notebook PCs and portable electronic devices, he added.

In addition to RF suppression circuitry, the Boomer amplifier offers four flexible gain selections from 6 dB to 21.6 dB, using a two-bit gain select. When operating on a single 5 V supply, it delivers 1.2 W, 1.9 W or 2.1 W (typical) of output power to an 8Ω, 4 Ω, or 3Ω bridge-tied load (BTL), respectively. The amplifier delivers high-quality output power from a surface-mount package, requires few external components, has an active-low micropower shutdown mode input and provides thermal shutdown protection.

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Available now in a 20-pin exposed-DAP TSSOP package, the LM4884 is priced at $1.40 in 1,000-unit quantities. Click here for the LM4884 data sheet.

National Semiconductor , 1-800-272-9959,

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