SI4706-C31 Datasheet, PDF (17/36 Pages) Silicon Laboratories – HIGH-PERFORMANCE FM RDS/RBDS RECEIVER

Si4706-C31
4. Functional Description
4.1. Overview
Half-wavelength
antenna
FMI
Integrated
antenna
LPI
RFGND
32.768 kHz _(TYP)
RCLK
2.7–5.5 V _VDD
LNA
AGC
0/90
AFC
REG
XTAL
OSC
ADC
PGA
DSP
ADC
RSSI RDS
CONTROL
INTERFACE
Si4706
DAC
LOUT
DAC
ROUT
GPO
DCLK
DOUT
DFS
Figure 9. Functional Block Diagram
The Si4706-C31 offers advanced audio processing plus
advanced RDS processing in a very small, 100%
CMOS receiver integrated circuit. The device provides
both analog and digital audio out, and a highly flexible
RDS pre-processor and 100 block RDS buffer. It is an
ideal product for handsets and portable devices seeking
to optimize both sound and data receiver performance.
For sound, the advanced audio processing is
unprecedented in portable devices. For RDS data
applications such as song-tagging, meta-data, traffic
message channel, or other open data applications, the
advanced and patented R(B)DS decoding engine offers
outstanding data synchronization and integrity. The
RDS engine includes demodulation, symbol decoding,
advanced error correction, detailed visibility to block-
error rates (BLER), advanced decoder reliability, and
synchronization status. The Si4706 provides complete,
decoded and error-corrected RDS groups (100 blocks),
up to 25 groups at a time. The Si4706 offers several
modes of operation for various applications which
require more or less visibility to the RDS status and
group data.
*Note: The term “RDS” will be used to mean “RDS/RBDS”
throughout the document.
The Si4706 receiver draws on Silicon Laboratories’
broadcast audio know-how and patent portfolio, using a
digital low intermediate frequency (low-IF) receiver
architecture proven by hundreds of millions of Silicon
Laboratories’ broadcast audio receivers shipped
worldwide.
Silicon Labs has shipped 1/2 billion broadcast audio
receivers worldwide using this architecture. The low-IF
architecture allows the Si4706 to deliver superior
performance while integrating the great majority of
external components required by competing solutions.
The Si4706 digital integration reduces the required
external components of traditional offerings, resulting in
a solution requiring only an external bypass capacitor
and occupying board space of approximately 15 mm².
The Si4706supports embedded antenna technology,
allowing the FM antenna to be integrated into the
enclosure or PCB of a portable device. Refer to “AN383:
Si47xx Antenna, Schematic, Layout, And Design
Guidelines” for antenna design guidelines.
The Si4706 is feature-rich, providing highly automated
performance with default settings and extensive
programmability and flexibility for customized system
performance.
Rev. 1.0
17