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E93930D78
Sony reserves the right to change products and specifications without prior notice. This information does not convey any license by
any implication or otherwise under any patents or other right. Application circuits shown, if any, are typical examples illustrating the
operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits.
Dolby B Type Noise Reduction System with Recording/Playback Equalizer
CXA1897Q
Absolute Maximum Ratings (Ta=25C)
Supply voltage
V
CC
12
V
Operating temperature
Topr
20 to +75
C
Storage temperature
Tstg
65 to +150
C
Allowable power dissipation
P
D
735
mW
Operating Conditions
Supply voltage
V
CC
6.5 to 10.0
V
Description
The CXA1897Q is an analog signal processing IC
for tape recorders. It achieves whole processing
operations for the recording and playback systems
which include the Dolby B noise reduction function
on a single chip. This IC supports 2 channels at
each function.
Features
Dolby B noise reduction supports 1.7 times normal
speed.
Recording/playback equalizer amplifier supports
1.7 times normal speed.
Built-in comparator for AMS (automatic music
sensor)
Built-in AGC (automatic gain control) with amplifier
for MPX filter.
Playback equalizer outputs independently for
DECK-A and DECK-B.
Externally adjustable recording equalizer Gp and
fp.
Built-in Recording mute function.
Double cassette dubbing system can be easily
configured just with this IC.
Applications
All analog signal processing in cassette deck parts
of tape recorders and compact music centers
(Sankyo Seiki mfg. Co., Ltd. YK47R-KF202 or
equivalent which has the same head type.)
Structure
Bipolar silicon monolithic IC
48 pin QFP (Plastic)
These ICs are available only to the licensees of Dolby Laboratories Licensing Corporation from whom licensing and applications
information may be obtained.
"Dolby" and the double D symbols are trade marks of Dolby Laboratories Licensing Corporation.
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CXA1897Q
Pin Description
(Ta=25C, Vcc=8 V, no signals)
Pin
Symbol
DC
I/O
I/O
Equivalent circuit
Description
No.
voltage
resistance
1
Vcc
8.0V
--
--
2
RFC
8.0V
--
--
3
AMS OUT
8.0V
O
--
4
AMS GAIN
2.8V
--
--
5
AGC IN1
4.0V
I
50k
32 AGC IN2
Power supply pin.
Connects the resistor and
capacitor for providing a ripple
eliminated stable voltage in
the power supply.
AMS output pin.
Connects the resistor and
capacitor which determine the
attack and recovery time
constants of the output to Vcc.
No signal supplied
High
level
Signal supplied
Low level
Connects the resistor which
determines the AMS signal
detection level.
AGC signal input pin.
The input resistance varies
from 50k
to 10k
.
AGC is applied when a signal
of 30dB or more level is input
to AGC.
(Pin 33 external 47F //
300k
)
2
Vcc
GND
147
3
3
Vcc
250
to RFS
3
Vcc
GND
147
2
4
Vcc
GND
147
2
Vcc
10k
5p
32
Vcc
GND
147
Vcc
10k
40k
5
VGS
4
1
Vcc
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