文档介绍：Rev. 5/05 Copyright ? 2005 by Silicon Laboratories AN231 Silicon Laboratories Confidential. Information contained herein is covered under non-disclosure agreement (NDA). AN231 S I 4700/01 H EADPHONE AND A NTENNA I NTERFACE 1. Introduction Silicon Laboratories' Si 4700/01 family of FM tuners is the industry's smallest, most integrated, and highest performing FM tuner solution on the market. The Si4700/01 integrates the entire FM radio tuner from the antenna input to the audio output including t he selectivity filtering, automatic gain control, frequency synthesizer, RDS/ RBDS decoding (Si4701 only) and audio processing. Reduci ng ponent count by more than 90 percent and board space by about 70 percent versus p etitive products, the Si4700/ 01 FM tuner family allows an RF radio tuner to be added to virt ually any portable device because of it pact size and low bill-of-material cost. The Si4700/01 FM tuner family ponent count by more than 90% and board space by over 65%, allowing high-quality FM tuning to be added to virtually any portable device. This application note describes an example of how to interface the Si4700/01 to a 3-wire headphone with mon wire of the headphone used as the antenna. In this design, we use the National Semiconductor LM4910 audio amplifier to drive a 32 ? headphone, but any audio amplifier or audio baseband codec can be used so long as th