SA1021
FM RADIO RECEIVER FOR PORTABLE SYSTEM
DESCRIPTION
The SA1021 integrated radio receiver circuit is for portable radios,
stereo as well as mono, where a minimum of periphery is important in
terms of small dimensions and low cost. It is fully compatible for
applications using the low-voltage micro tuning system (MTS). The IC
has a frequency locked loop (FLL) system with an intermediate
frequency of 76kHz. The selectivity is obtained by active RC filters.
The only function to be tuned is the resonant frequency of the
oscillator.Interstation noise as well as noise from receiving weak
signals is reduced by a correlation mute system.
Special precautions have been taken to meet local oscillator
radiation requirements. Because of the low intermediate frequency,
low pass filtering of the MUX signal is required to avoid noise when
receiving stereo. 50kHz roll-off compensation, needed because of the
low pass characteristic of the FLL, is performed by the integrated LF
amplifier. For mono application this amplifier can be used to directly
drive an earphone. The field-strength detector enables field-strength
dependent channel separation control.
SOP-16-225-1.27
ORDERING INFORMATION
Part No.
SA1021
* Mixer
* IF amplifier/limiter
* Mute circuit
* Loop amplifier
* LF amplifier for mono earphone
amplifier or MUX filter
Package
SOP-16-225-1.27
FEATURES
* RF input stage
* Local oscillator
* Frequency detector
* MTS compatible
* Internal reference circuit
* Field-strength dependent channel separation control facility.
BLOCK DIAGRAM
12
13
11
10
7
8
RF
MIX
AMP
Buffer
IF Filter
5
OSC
VCO
MUTE
CLIM
6
Demodulation
IF limiter
AF
AMP
STAB
14
16
15
2
1
3
4
9
Fig.1 Block diagram
HANGZHOU SILAN MICROELECTRONICS CO.,LTD
Http: www.silan.com.cn
REV:2.0
2004.07.31
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