SI4712-B30 Datasheet, PDF (20/42 Pages) Silicon Laboratories – FM RADIO TRANSMITTER WITH RECEIVE POWER SCAN

Si4712/13-B30
5. Functional Description
5.1. Overview
Tx
Ant
TXO
L1
120 nH
RFGND
AFC
Si4712/13
PEAK
DETECT
DIGITAL
DIN
AUDIO
DFS
DSP
DAC
ADC
LIN
DAC
ADC
RIN
CONTROL
INTERFACE
GPO
RDS (Si4713)
LDO
VDD 2.7–5.5 V
GND C1
22 nF
Figure 13. Functional Block Diagram
The Si4712/13 is the first 100% CMOS FM radio
transmitter with integrated receive functionality to
measure received signal strength. The device leverages
Silicon Labs’ highly successful and proven Si4700/01
FM receiver patent family and offers unmatched
integration and performance, allowing FM transmit to be
added to any portable device with a single chip. The
Si4712/13 offers industry-leading size, performance,
low power consumption, flexibility, and ease of use.
The Si4712/13’s digital integration reduces the required
external components of traditional offerings, resulting in
a solution requiring only an external inductor and
bypass capacitor, and PCB space of approximately
15 mm². This increases the device reliability and
simplifies the design and manufacturing for companies
adopting this technology.
The Si4712/13’s integrated receive power scan function
shares the same antenna as the transmitter allowing for
a compact printed circuit board design. The device
operates in half duplex mode, meaning the transmitter
and receiver do not operate at the same time.
The Si4712/13 performs FM modulation in the digital
domain to achieve high fidelity, optimal performance
versus power consumption, and flexibility of design. The
onboard DSP provides modulation adjustment and
audio dynamic range control for optimum sound quality.
The Si4713 supports the European Radio Data System
(RDS) and the US Radio Broadcast Data System
(RBDS) including all the symbol encoding, block
synchronization, and error correction functions. Using
this feature, the Si4713 enables data such as artist
name and song title to be transmitted to an RDS/RBDS
receiver.
The transmit output (TXO) connects directly to the
transmit antenna with only one external inductor to
provide harmonic filtering. The output is programmable
over a 10 dB voltage range in 1 dB steps. The TXO
output pin can also be configured for loop antenna
support. Users are responsible for complying with local
regulations on RF transmission (FCC, ETSI, ARIB,
etc.).
The digital audio interface operates in slave mode and
supports a variety of MSB-first audio data formats
including I²S and left-justified modes. The interface has
three pins: digital data input (DIN), digital frame
synchronization input (DFS), and a digital bit
synchronization input clock (DCLK). The Si4712/13
supports a number of industry-standard sampling rates
20
Rev. 1.1