Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.comRev. 1.0 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • November 9, 2021Si4720/21-B20B ROADCAST FM R ADIO T RANSCEIVER FOR P ORTABLE A PPLICATIONSFeaturesApplicationsDescriptionThe Si4720/21 integrates the complete tuner and transmit functions forFM broadcast reception and standards-compliant, unlicensed FMbroadcast stereo transmission. Users must comply with local radiofrequency (RF) transmission regulations. Full FM RX and TX in 3 x 3 QFN Worldwide FM RX band support Compliant with worldwide FM TXregulations Excellent real-world performance Supports integrated TX/RXantenna Programmable transmit outputvoltage Frequency synthesizer withintegrated VCO Integrated LDO regulator Minimal BOM (15 mm2) Digital audio output(Si4721 only) Digital audio input Adjustable seek parameters Adjustable mono/stereo blend Adjustable soft mute Advanced modulation control Audio dynamic range control Audio silence detector Programmable reference clockinput 2-wire and 3-wire controlinterface 2.7 to 5.5 V supply voltage 3 x 3 x 0.55 mm 20-pin Pb-freeQFN package RDS/RDBS encoder/decoder(Si4721 only) Cellular handsets/hands-free MP3 players Portable media players Wireless speakers/microphone Satellite digital audio radios Personal computers/notebooksFunctional Block DiagramADCADCSi4720/21DSPDACDACPGAAFCFMIAGCTx/Rx AntRx Ant*TXORFGNDCONTROLINTERFACEGPOLIN/DFSRIN/DOUTROUT/DINLOUT/DFSLDOVDDGND2.7–5.5 VC122 uFL1120 nHLNA*Note: Dedicated Rx antenna is optionalSi4720/21(Top View)Patents pendingNotes:1.To ensure proper operation and FMtransceiver performance, follow theguidelines in “AN383: 3 mm x 3 mmQFN Universal Layout Guide.”Skyworks will evaluate schematics andlayouts for qualified customers.2.Place the Si4720/21 as close aspossible to the antenna jack, and keepthe FMI trace as short as possible.Ordering Information:See page 41.Pin AssignmentsGNDPAD1231718192011121314678945161015 RIN/DOUTLOUT/DFSROUT/DINGNDRSTNCTXOVDDFMIRFGND
