![](http://datasheet.mmic.net.cn/370000/TDA8446_datasheet_16738667/TDA8446_4.png)
1995 Feb 16
4
Philips Semiconductors
Product specification
Fast RGB/YC switch for digital decoding
TDA8446
PINNING
SYMBOL
PIN
DESCRIPTION
DIP20
SO28
SOUT
1
1
synchronization signal output; this output provides the synchronization information
extracted from the incoming signal at pin 2 (SIN).
synchronization signal input; CSYNC or CVBS signal from the peri-connector
clamping capacitor connection; the clamping pulse is generated by external circuitry
connected to this pin, the generated pulse clamps the RGB inputs.
not connected
clamping pulse output
not connected
B-signal input
G-signal input
R-signal input
clamping control signal input; this TTL signal is used to select the clamp signal, a LOW
level at this input forces the circuit to output the generated clamping pulse.
not connected
clamping pulse input; this TTL signal indicates the black level clamping period for the
incoming Y signal (active-HIGH).
chrominance signal input
chrominance signal output
luminance signal input; this input also accepts the CVBS signal
fast switching signal input; this signal is used to control fast switching of the luminance
signals, a HIGH level at this input forces the circuit to output the internal Y signal.
not connected
not connected
gain control signal input; this TTL signal is used to set the gain of the chrominance
amplifiers (A), a LOW level at this input forces the gain A to 6 dB (HIGH forces to 0 dB).
not connected
(R
Y) signal output
luminance signal output
(B
Y) signal output
not connected
not connected
positive supply voltage (+12 V)
internal decoupling
ground
SIN
CCL
2
3
2
3
n.c.
CLO
n.c.
BIN
GIN
RIN
SW1
4
5
6
7
8
4
5
6
7
8
9
10
n.c.
CLI
9
11
12
CIN
COUT
YIN
FS
10
11
12
13
13
14
15
16
n.c.
n.c.
SW2
17
18
19
14
n.c.
(R-Y)
YOUT
(B
Y)
n.c.
n.c.
V
CC
VINT
V
EE
20
21
22
23
24
25
26
27
28
15
16
17
18
19
20