NATIONAL Semiconductor, represented in Australia by Arrow Electronics , has released the LM4884 Boomer audio amplifier, with internal circuitry that suppresses RF signals, preventing them from passing through the amplifier.
Certain types of RF signals can create distracting noise that is heard through the speaker. The LM4884 suppresses strong RF signals and produces clean sound in laptop computers with WiFi/802.11, GSM cards or modems. It also suppresses RF noise generated by mobile phones or other wireless devices operating in close proximity to the notebook computer.
In addition to RF suppression circuitry, the audio amplifier offers four flexible gain selections from 6dB to 21.6dB, using a two-bit gain select. When operating on a single 5V supply, it delivers 1.2W, 1.9W or 2.1W (typical) of output power to an 8Ω, 4Ω or 3Ω bridge-tied load (BTL), respectively.
The LM4884 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.