SI4707-B20 Datasheet, PDF (14/30 Pages) Silicon Laboratories – WEATHER BAND AND SAME DATA RECEIVER

Si4707-B20
4. Functional Description
4.1. Overview
Weather Band
Antenna
FMI
RFGND
32.768 kHz
RCLK
2.7–5.5 V _VDD
LNA
AGC
0/90
AFC
REG
XTAL
OSC
ADC
PGA
DSP
ADC
RSSI /
SNR
SAME
CONTROL
INTERFACE
Si4707
DAC
LOUT
DAC
ROUT
GPO
GPO
Figure 8. Functional Block Diagram
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.
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Rev. 0.8