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).

SIN

2

2

synchronization signal input; CSYNC or CVBS signal from the peri-connector

CCL

3

3

clamping capacitor connection; the clamping pulse is generated by external circuitry

connected to this pin, the generated pulse clamps the RGB inputs.

n.c.

−

4

not connected

CLO

4

5

clamping pulse output

n.c.

−

6

not connected

BIN

5

7

B-signal input

GIN

6

8

G-signal input

RIN

7

9

R-signal input

SW1

8

10

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.

n.c.

−

11

not connected

CLI

9

12

clamping pulse input; this TTL signal indicates the black level clamping period for the

incoming Y signal (active-HIGH).

CIN

10

13

chrominance signal input

COUT

11

14

chrominance signal output

YIN

12

15

luminance signal input; this input also accepts the CVBS signal

FS

13

16

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.

n.c.

−

17

not connected

n.c.

−

18

not connected

SW2

14

19

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).

n.c.

−

20

not connected

−(R-Y)

15

21

−(R−Y) signal output

YOUT

16

22

luminance signal output

−(B−Y)

17

23

−(B−Y) signal output

n.c.

−

24

not connected

n.c.

−

25

not connected

18

26

positive supply voltage (+12 V)

VINT

19

27

internal decoupling

20

28

ground