SI4736-C40-GUR Datasheet, PDF (20/42 Pages) Silicon Laboratories – BROADCAST AM/FM RADIO RECEIVER

Si4736/37/38/39-C40
5. Functional Description
5.1. Overview
AMI
AM
ANT
RFGND
FM/
WB
ANT
FMI
2.7– 5.5 V (QFN)
2.0– 5.5 V (SSOP) VDD
GND
LNA
AGC
LNA
AGC
LDO
Si473x
RDS
(Si4737/
39)
LOW-IF
DIGITAL
AUDIO
(Si4737/
39)
DOUT
DFS
GPO/DCLK
ADC
DAC
DSP
ADC
DAC
ROUT
LOUT
AFC
CONTROL
INTERFACE
VIO
1.85–3.6 V
Figure 9. Functional Block Diagram
The Si4736/37 and Si4738/39 are the industry's first
fully integrated, 100% CMOS AM/FM/WB and FM/WB
radio receiver ICs. Offering unmatched integration and
PCB space savings, the Si4736/37/38/39 requires only
two external components and less than 15 mm² of
board area, excluding the antenna inputs. The
Si4736/37/38/39 AM/FM/WB radio provides the space
savings and low power consumption necessary for
portable devices while delivering the high performance
and design simplicity desired for all AM/FM/WB
solutions.
Leveraging Silicon Laboratories' proven and patented
Si4700/01 FM tuner's digital low intermediate frequency
(low-IF) receiver architecture, the Si4736/37/38/39
delivers superior RF performance and interference
rejection in both AM and FM bands. The high integration
and complete system production test simplifies design-
in, increases system quality, and improves
manufacturability.
The Si4736/37/38/39 is a feature-rich solution including
1050 Hz tone detection, advanced seek algorithms, soft
mute, auto-calibrated digital tuning, and FM stereo
processing. In addition, the Si4736/37/38/39 provides
analog and digital audio outputs and a programmable
reference clock. The device supports I²C-compatible, 2-
wire control interface, SPI, and a Si4700/01 backwards-
compatible, 3-wire control interface.
The Si4736/37/38/39 utilizes digital processing to
achieve high fidelity, optimal performance, and design
flexibility. The chip provides excellent pilot rejection,
selectivity, and unmatched audio performance, and
offers both the manufacturer and the end-user
extensive programmability and flexibility in listening
experience.
The Si4737/39 incorporates a digital processor for the
European Radio Data System (RDS) and the North
American Radio Broadcast Data System (RBDS), and
includes all required symbol decoding, block
synchronization, error detection, and error correction
functions. Using this feature, the Si4737/39 enables
broadcast data such as station identification and song
name to be displayed to the user.
5.2. Operating Modes
The Si4736/37/38/39 operates in an FM receive, an AM
receive, or a weather band receive mode. In FM mode
and WB mode, radio signals are received on FMI and
processed by the FM front-end circuitry. In AM mode,
radio signals are received on AMI and processed by the
AM front-end circuitry. In addition to the receiver mode,
there is a clocking mode to choose to clock the
Si4736/37/38/39 from a reference clock or crystal. On
the Si4731, there is an audio output mode to choose
between an analog and/or digital audio output. In the
analog audio output mode, ROUT and LOUT are used
for the audio output pins. In the digital audio mode,
DOUT, DFS, and DCLK pins are used. Concurrent
analog/digital audio output mode is also available
requiring all five pins. The receiver mode and the audio
output mode are set by the POWER_UP command
listed in Table 15, “Selected Si473x Commands,” on
page 27.
20
Rev. 1.0