Sony CXA1645P, CXA1645M Datasheet

RGB Encoder

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Description

The CXA1645P/M is an encoder IC that converts
analog RGB signals to a composite video signal. This
IC has various pulse generators necessary for
encoding. Composite video outputs and Y/C outputs for
the S terminal are obtained just by inputting composite
sync, subcarrier and analog RGB signals.

It is best suited to image processing of personal
computers and video games.

Features

• Single 5V power supply

• Compatible with both NTSC and PAL systems

• Built-in 75Ω drivers

(RGB output, composite video output, Y output, C

output)

• Both sine wave and pulse can be input as a

subcarrier.

• Built-in band pass filter for the C signal and delay

line for the Y signal

• Built-in R-Y and B-Y modulator circuits

• Built-in PAL alternate circuit

• Burst flag generator circuit

• Half H killer circuit

CXA1645P/M

24 pin DIP (Plastic)

Structure

Bipolar silicon monolithic IC

Absolute Maximum Ratings

• Supply voltage VCC 14 V

• Operating temperature Topr –20 to +75 °C

• Storage temperature Tstg –65 to +150 °C

• Allowable power PD CXA1645P 1250 mW

dissipation CXA1645M 780 mW

Recommended Operating Condition

Supply voltage VCC1, 2 5.0 ± 0.25 V

24 pin SOP (Plastic)

Applications

Image processing of video games and personal
computers

Block Diagram and Pin Configuration

24

1

23

R-OUT

CLAMP CLAMP CLAMP

2

22

G-OUT

3

21

B-OUT

4

20

MATRIX

5

VIDEO

OUT

CC2BOUTGOUTROUTGND2 VREF IREFCVOUT

19

DELAY

SIN-PULSE

6

18

CLAMP

7

Y/C
MIX

SHIFTER

17

PHASE

8

16

75

DRIVER75DRIVER

SYNC

ADD

R-Y
Modulator

B-Y
Modulator

PULSE

9

COUTYOUTYTRAPFOV

15

BPF

GEN

10

SYNCINYCLPCBFOUTNPINSCINBINGINRINGND1 NC V

14

REGULATOR

11

13

12

CC1NC

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.

– 1 –

E93411A41-ST

CXA1645P/M

Pin Description

Pin
No.

Symbol Pin voltage

1

GND1

RIN

2

GIN

3

BIN

4

NC

5

∗

0V

Black level

when

clamped

2.0V

Equivalent circuit Description

Ground for all circuits other than RGB,
composite video and Y/C output circuits.
The leads to GND2 should be as short and
wide as possible.

VCC1

Analog RGB signal inputs. Input
100%, = 1Vp-p (max.). To minimize clamp
error, input at as low impedance as

2
3
4

100µ

ICLP

180µ

100µ

GND1

possible.
ICLP turns ON only in the burst flag period.

NO CONNECTION

V

CC1

∗

Externally applied voltage

Subcarrier input.

SCIN

6

NPIN

7

—

1.7V

20k

129

3k

20P

80k

20k

2.5V

68k

32k

100µ

GND1

CC1

V

GND1

CC1

V

6

7

Input 0.4 to 0.5Vp-p sine wave or pulse.
Refer to Notes on Operation, Nos. 3 and 5.

Pin for switching between NTSC and PAL
modes

NTSC: VCC, PAL: GND

8

BFOUT

H : 3.6V

L : 3.2V

8

129

25µ

25µ

GND1

BF pulse monitoring output. Incapable of
driving a 75Ω load.

– 2 –

CXA1645P/M

Pin
No.

9

10

Symbol Pin voltage

YCLPC

SYNC
IN

2.5V

2.2V

Equivalent circuit Description

V

CC1

129

9

Pin to determine the Y signal clamp time
constant.
Connect to GND via a 0.1µF capacitor.

40k

1.6V
GND1

CC1

V

5µ

Composite sync signal input. Input TTL-

10

4k

level voltages.

L ( ≤ 0.8V): SYNC period
H ( ≥ 2.0V)

2.2V
GND1

12

13

14

VCC1

IREF

VREF

5.0V

2.0V

4.0V

∗

composite video and Y/C output circuits.
Refer to Notes on Operation. Nos. 4 and 10.

Power supply for all circuits other than RGB,

V

CC1

Pin to determine the internal reference
current.

13

129

50µ

GND1

V

CC1

Connect to GND via a 47kΩ resistor.

Internal reference voltage.
Connect a decoupling capacitor of

14

approximately 10µF.

GND1

– 3 –

Refer to Notes on Operation, Nos. 4 and 7.

CXA1645P/M

Pin

No.

15

16

Symbol Pin voltage

COUT

YOUT

2.2V

Black level

1.3V

Equivalent circuit Description

V

CC2
CC1

V

600µ

Chroma signal output. Capable of driving a
75Ω load.

15

20k

GND2

V
V

600µ

CC2
CC1

Refer to Notes on Operation, Nos. 6 and 9.

10k

Y signal output. Capable of driving a 75Ω
load.

16

20k

Refer to Notes on Operation, Nos. 6 and 9.

10k

17

18

YTRAP

FO

Black level

1.6V

2.0V

17

8.5k

1.5k

Input resistance 1.5kΩ

18

129

0.5P

GND2

V

CC1

GND1

V

CC1

50µ

Pin for reducing cross color caused by the
subcarrier frequency component of the Y
signal. When the CVOUT pin is in use,
connect a capacitor or a capacitor and an
inductor in series between YTRAP and
GND. Decide capacitance and inductance,
giving consideration to cross color and the
required resolution.
No influence on the YOUT pin.

Refer to Notes on Operation, No. 8.

Internal filter fo adjustment pin.
Connect to GND via the following resistor
according to the NTSC or PAL mode.

NTSC: 20kΩ (±1%)
PAL : 16kΩ (±1%)

GND1

– 4 –

CXA1645P/M

Pin

No.

19

20

Symbol Pin voltage

VCC2

CVOUT

Black level

5.0V

1.2V

∗

Equivalent circuit Description

Power supply for RGB, composite video and
Y/C output circuits. Decouple this pin with a
large capacitor of 10µF or above as a high
current flows.

Refer to Notes on Operation, Nos. 4 and 10.

VCC2
V

CC1

600µ

Composite video signal output. Capable of
driving a 75Ω load.

20

500µ

20k

GND2

CC2

V
V

CC1

Refer to Notes on Operation, Nos. 6 and 9.

10k

21
22
23

24

BOUT
GOUT
ROUT

GND2

Black level

1.7V

∗

0V

21
22
23

Analog RGB signal outputs. Capable of
driving a 75Ω load.

5.5k

Refer to Notes on Operation, Nos. 6 and 9.

200µ

GND1
GND2

Ground for RGB, composite video and Y/C
output circuits. The leads to GND1 should
be as short and wide as possible.

– 5 –