Si4707 Weather Band and SAME Data Receiver Description Features The Si4707 is the industry's first weather band (WB) radio receiver IC to include a specific area message encoding (SAME) processor. Offering unmatched integration and PCB space savings, the Si4707 requires only one external component and less than 15 mm2 of board area. Available in a tiny 3 x 3 mm QFN package, it eliminates the need for a front-end tuner IC, external ADC, DSP processor, RAM, and numerous discrete components found in traditional SAME weather band radios. The Si4707 weather band receiver provides the space savings and low power consumption necessary for portable devices while delivering the high performance and design simplicity desired for all weather alert radios. Leveraging Silicon Laboratories' proven and patented Si4700/01 FM tuner's digital low intermediate frequency (low-IF) receiver architecture, the Si4707 delivers superior RF performance combined with sophisticated digital processing to yield best-in-class audio quality and SAME data sensitivity. The high integration and complete system production test simplifies design in, increases system quality, and improves manufacturability. The Si4707 is a feature-rich solution including 1050 Hz tone detection, automatic frequency control, dynamic channel bandwidth filters, and digital tuning. In addition, the Si4707 provides a programmable reference clock and supports an I2C compatible 2-wire control interface, SPI, and a Si4700/01 backwards compatible 3-wire control interface. The Si4707 incorporates a digital processor to provide SAME data, advance error correction, and SAME data quality metrics. Using this feature, the Si4707 enables broadcast alert data such as severe thunderstorm warning or flash flood watch to be displayed to the user. - Weather band support (162.4–162.55 MHz) - SAME processor - Excellent SAME sensitivity - Byte-wise data quality metrics - Advanced error correction - 1050 Hz alert tone detection - Excellent real-world performance - Freq synthesizer with integrated VCO - Automatic frequency control (AFC) - Automatic gain control (AGC) - Adaptive noise suppression - WB digital tuning - Low-IF direct conversion with no external ceramic - filters Programmable reference clock Volume control Receive signal quality indicators (RSSI and SNR) 2-wire and 3-wire control interface Integrated LDO regulator 2.7 to 5.5 V supply voltage Firmware upgradeable 3 x 3 x 0.55 mm 20-pin QFN package - Pb-free/RoHS compliant Applications - Emergency radios Table and portable radios Stereos Mini/micro systems Portable media players Boom boxes Cellular handsets Modules Clock radios Mini HiFi Si4707 Weather Band Antenna ADC FMI RFGND LNA PGA DAC LOUT DAC ROUT GPO GPO DSP ADC AGC 0/90 RSSI / SNR SEN REG CONTROL INTERFACE XTAL OSC Weather Band VIO VDD SAME RST 2.7–5.5 V AFC SDIO RCLK SCLK 32.768 kHz Copyright © 2008 by Silicon Laboratories 4.2.08 Si4707 Weather Band and SAME Data Receiver Selected Weather Band Electrical Specifications Parameter Input Frequency Sensitivity Adjacent Channel Selectivity Audio S/N AFSK Trip Sensitivity Symbol fR SINAD = 12 dB ±25 kHz 100% of message correctly received Supply Voltage Interface Supply Voltage Supply Current Powerdown Current Audio Frequency Response Low Audio Frequency Response High VD, VA VIO IFM IPD GPO1 GPO2/INT GPO3 NC 1 NC Pin Assignments NC 20 19 18 17 16 FMI 2 Test Condition –3 dB –3 dB Min 162.4 — — — — Typ — 0.9 52 45 0.7 Max 162.55 — — — — Unit MHz µV EMF dB dB µV EMF 2.7 1.5 — — 5.5 3.6 V V — — 3 19.1 — — — 300 — µA Hz kHz 3 x 3 x 0.55 mm, 20-pin QFN Package Information 15 NC RFGND 3 14 LOUT GND PAD NC 4 13 ROUT 6 7 8 9 10 SCLK SDIO RCLK VIO 12 GND SEN RST 5 11 VDD Symbol A A1 b c D D2 e E E2 Weather Band Millimeters Symbol Min Nom Max 0.50 0.00 0.18 0.27 0.55 0.02 0.25 0.32 3.00 BSC 1.70 0.50 BSC 3.00 BSC 1.70 0.60 0.05 0.30 0.37 1.60 1.60 1.80 f L L1 aaa bbb ccc ddd eee Millimeters Min Nom Max 0.35 0.00 — — — — — 2.53 BSC 0.40 — — — — — — 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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