Datasheet

RDA Microelectronics, Inc. RDA5807M FM Tuner V1.1
The information contained herein is the exclusive property of RDA and shall not be distributed, reproduced, or disclosed in whole or in
part without prior written permission of RDA.
Page 3 of 22
2 Functional Description
I
ADC
L
DAC
R
DAC
Q
ADC
+
-
Audio
DSP
Core
digital filter
MPX decoder
stereo/mono
audio
VCO
Synthesizer
Interface
Bus
RSSI
SDIO
SCLK
MCU
RDA5807M
LOUT
ROUT
FMIN
RCLK
2.7-3.3 V
32.768 KHz
VDD
LDO
Limiter
LNA
I
PGA
Q
PGA
RDS
/RBDS
Figure 2-1. RDA5807M FM Tuner Block Diagram
2.1 FM Receiver
The receiver uses a digital low-IF architecture that
avoids the difficulties associated with direct
conversion while delivering lower solution cost
and reduces complexity, and integrates a low
noise amplifier (LNA) supporting the FM
broadcast band (50 to 115MHz), a multi-phase
image-reject mixer array, a programmable gain
control (PGA), a high resolution analog-to-digital
converters (ADCs), an audio DSP and a high-
fidelity digital-to-analog converters (DACs).
The limiter prevents overloading and limits the
amount of intermodulation products created by
strong adjacent channels.
The multi-phase mixer array down converts the
LNA output differential RF signal to low-IF, it also
has image-reject function and harmonic tones
rejection.
The PGA amplifies the mixer output IF signal and
then digitized with ADCs.
The DSP core finishes the channel selection, FM
demodulation, stereo MPX decoder and output
audio signal. The MPX decoder can autonomous
switch from stereo to mono to limit the output
noise.
The DACs convert digital audio signal to analog
and change the volume at same time. The DACs
has low-pass feature and -3dB frequency is about
30 KHz.
2.2 Synthesizer
The frequency synthesizer generates the local
oscillator signal which divide to multi-phase, then
be used to downconvert the RF input to a
constant low intermediate frequency (IF). The
synthesizer reference clock is 32.768 KHz.
The synthesizer frequency is defined by bits
CHAN[9:0] with the range from 50MHz to
115MHz.
2.3 Power Supply
The RDA5807M integrated one LDO which
supplies power to the chip. The external supply
voltage range is 2.7-3.3 V.