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RC5512
PRODUCT SPECIFICATION
2
Functional Description
The Rapper Stereo Sound Driver is an audio device that can
be used on PC motherboards and add-in sound cards. It con-
sists of stereo output drivers for headphone or speakers, a
low noise microphone amplifier with AGC, and a regulator to
provide a clean 5V supply. The RC5512 has two microphone
inputs which are user selectable. Each section can be individ-
ually put into a shut-down mode and muted by pulling the
appropriate pin low.
The output drivers can deliver up to 2 watts peak and 4 watts
peak into 8
W
and 4
W
speakers, respectively, from a 12V
source. The drivers use class AB amplifiers and maintain a
low bias current. The power-down function is designed to
save power and to turn on/off the driver without generating
popping
signals. To prevent popping signals, when the cir-
cuit is activated, a delay is provided to these output drivers.
These drivers become active only after their outputs have set-
tled. The time constant is user-defined through an external
capacitor (C
DELAY
) on the SFTSTART pin.
The microphone amplifier feeds into an AGC with a dynamic
range of 40dB. An external capacitor is used to provide
attack and decay features. Attack and decay times can be var-
ied linearly by varying an external capacitor (C
AGCTC pin. The attack and decay time ratio has been set for
pleasant audio quality.
AD
) on the
The 12 V to 5V voltage regulator can provide up to 20mA of
current without external components. It can provide a noise-
free regulated voltage supply to the other devices that com-
plete the sound channel. Use of an external transistor can
boost the regulator output to 150mA or higher with the
appropriate thermal precautions. The line regulation of 50dB
improves the cross talk and the power supply rejection ratio
of all other audio blocks that are supplied by the 5V source.
The thermal limiting circuitry activates if the chip tempera-
ture typically exceeds 150
°
C.
Pin Assignments
V
R
R
L
V
L
S
M
M
R
G
M
V
R
VCCDROPL
SPKOUTL
GNDSPKL
GNDSPKR
SPKOUTR
SFTSTART
VCCDROPR
5
6
7
8
9
10
11
25
65-5512-02
24
23
22
21
20
19
1
1
1
1
1
1
1
4
3
2
1
2
2
2
REGPD
GNDREG
SPKPD
GNDMIC
MICPD
MICSEL
AGCTC
RC5512