Si4720/21 Broadcast FM Radio Transceiver for Portable Applications Description Features The Si4720/21 is the first single chip FM radio transceiver. The proven and patented digital architecture of the Si4720/ 21 combines the functionality of the Si470x FM radio receiver with the Si471x FM transmitter, offering full FM receive and transmit capabilities in a single, ultra-small 3x3x0.55 mm QFN package. The device leverages Silicon Lab's highly successful and proven FM technology, and offers unmatched integration and performance allowing FM receive and transmit to be added to any portable device by using a single chip. As with the Si470x and Si471x products, the Si4720/21 offers industry leading size, performance, low power consumption, and ease of use. The Si4720/21's digital integration reduces the required external components of traditional offerings, resulting in a solution requiring only an external inductor and bypass capacitor, and a PCB space of approximately 15 mm2. The Si4720/21 is layout compatible with Silicon Laboratories' Si470x FM radio receivers, Si473x AM/FM radio receivers, and the Si471x FM radio transmitter solutions, allowing a single PCB layout to accommodate a variety of music features. High yield manufacturability, unmatched performance, easy design-in, and software programmability are key advantages of the Si4720/21. The Si4721 is the industry's first single-chip integrated FM radio transceiver including both receive and transmit support for the European Radio Data System (RDS) and the U.S. Radio Broadcast Data System (RBDS) standards. RDS allows digital information sent from the broadcaster to be displayed, such as station ID, song name and music category. In Europe, alternate frequency (AF) information is also provided to automatically change stations in areas where broadcasters use multiple frequencies. In transmit mode, digital information such as artist name, song title, music category, and branded messaging can be transmitted and displayed on any RDS/RBDS receiver. Users are responsible for adjusting their system's radiated power levels to comply with local regulations on RF transmission (FCC, ETSI, ARIB, etc.). - Integrated FM antenna support Excellent real-world performance Only two external components required Worldwide FM band support (76 to 108 MHz) RDS/RBDS processor (Si4721) Frequency synthesizer with integrated VCO Adjustable seek parameters Adjustable mono/stereo blend Adjustable soft mute Programmable transmit output voltage control Audio dynamic range control Advanced modulation control Analog/digital audio interface Programmable reference clock input Programmable pre/de-emphasis (50/75 µs) 2-wire and 3-wire control interface Integrated LDO regulator 2.7 to 5.5 V supply voltage 3x3x0.55 mm 20-pin Pb-free QFN package Applications - Cellular handsets/hands free MP3 players Portable media players GPS/navigation devices Satellite digital audio radios Personal computers Si4720/21 Tx/Rx Ant TXO LIN/DFS L1 120 nH RIN/DOUT ADC VDD FM Transceiver LOUT/DFS Copyright © 2008 by Silicon Laboratories SEN VIO CONTROL INTERFACE GPO GPO2/INT *Note: Dedicated Rx antenna is optional AFC GPO3/DCLK LDO GPO1 GND C1 22 uF RCLK 2.7–5.5 V DAC DSP ADC AGC ROUT/DIN RST PGA RFGND DAC SDIO LNA SCLK FMI MUX Headphone Rx Ant* 3.26.08 Si4720/21 Broadcast FM Radio Transceiver for Portable Applications Selected Electrical Specifications Parameter Frequency Range Sensitivity Headphone Matching Sensitivity 50 Matching Input IP3 Symbol fRF (S+N)/N = 26 dB (S+N)/N = 26 dB |f2 – f1| > 1 MHz; f0 = 2 x f1 – f2 AGC disabled ±200 kHz ±400 kHz Adjacent Channel Selectivity Alternate Channel Selectivity RX Audio Output Voltage RX Audio Mono S/N RX Audio THD Programmable Transmit Output Voltage, TXO Transmit Voltage Accuracy Transmit Channel Edge Power Transmit Adjacent Channel Power Pre/de-emphasis Time Constant TX Audio SNR TX Audio THD TX Audio Stereo Separation TX Sub Carrier Rejection Ratio TX Audio Input Signal Level (0 dB) Supply Voltage Interface Supply Voltage RX Supply Current TX Supply Current Test Condition VRF = 102–118 dBµV TX_PREMPHASIS = 75 µs TX_PREMPHASIS = 50 µs SCR VAI VDD VIO IRX ITX VIO = 1.8 V FM TX from Line Input NC 1 Typ — 2.2 1.1 105 Max 108 3.5 — — Unit MHz µV EMF µV EMF dBµV EMF 35 60 72 55 — — 50 70 80 63 0.1 118 — — 90 — 0.5 — dB dB mVrms dB % dBµV –2.5 — — 70 45 — — 30 40 — 2.7 1.5 — — — — –30 75 50 63 0.1 35 50 — — — 19.2 18.8 2.5 –20 –26 80 54 — — — — 0.636 5.5 3.6 22 22.8 dB dBC dBC us us dB % dB dB Vpk V V mA mA Package Information LIN/DFS GPO3/DCLK GPO2 GPO1 NC Pin Assignments Min 76 — — 100 20 19 18 17 16 FMI 2 15 RIN/DIO RFGND 3 14 LOUT/DFS GND PAD TXO 4 13 ROUTDIO 7 8 9 SDIO RCLK 10 11 VDD VIO 6 SCLK 12 GND SEN RST 5 Symbol A A1 b c D D2 e E E2 FM Transceiver Millimeters Nom 0.55 0.02 0.25 0.32 3.00 BSC 1.60 1.70 0.50 BSC 3.00 BSC 1.60 1.70 Min 0.50 0.00 0.18 0.27 Symbol Max 0.60 0.05 0.30 0.37 1.80 Millimeters Nom 2.53 BSC 0.35 0.40 0.00 — — — — — — — — — — — Min f L L1 aaa bbb ccc ddd eee Max 0.45 0.10 0.10 0.10 0.08 0.10 0.10 1.80 Copyright © 2008 by Silicon Laboratories Silicon Laboratories and Silicon Labs are trademarks of Silicon Laboratories Inc. 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