Sony CXA1785AR Datasheet

RGB Decoder/Driver

For the availability of this product, please contact the sales office.

Description

The CXA1785AR is an RGB decoder/driver designed to drive LCD panels. This IC converts composite video signals, Y/C signals and Y/color difference signals into RGB signals used for driving LCDs.

Features

• Both NTSC/PAL compatible

• Supports composite inputs, Y/C inputs and Y/color

difference input

• Band pass filter, trap and delay line

• Sharpness function

• γ compensation circuit

• R, B output delay time adjustment circuit

• Polarity reverse circuit

Applications

• Color liquid crystal viewfinders

• Liquid crystal projectors

• Industrial monitors

Structure

Bipolar silicon monolithic IC

CXA1785AR

48 pin LQFP (Plastic)

Absolute Maximum Ratings (Ta=25°C)

• Supply voltage VCC1-GND 6 V

• Supply voltage VCC2-VEE 15 V

• Supply voltage GND-VEE 10 V

• Input pin voltage VIN VCC1V

•Operating temperature Topr –30 to +85 °C

• Storage temperature Tstg –55 to +150 °C

• Allowable power dissipation

PD 560 mW

Operating Conditions

• Supply voltage VCC1-GND 4.25 to 5.25 V

• Supply voltage VCC2-GND 4.25 to 14.0 V

• Supply voltage VCC2-VEE 11.25 to 14.0 V

• Supply voltage VEE-GND –8.75 to 0 V

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—

E93Z28-TE

Block Diagram

CXA1785AR

SYNC O UT

SYNC SEP

EXT B IN

EXT G IN

EXT R IN

CONTRAST

F ADJ

CL AMP

AGC FILTER

AGC OUT

PICTURE

37

38

39

40

41

42

43

44

45

46

47

48

SYNC

SEP

BGP GEN

Vcc1

SYNC I N

BGP

SUB

CLAMP

AGC AMP

AGC DET

PI CT URE

REG1

COM P

TRA P

H. F ILTE R

CONTRAST R

SUB

CONTRAST B

DL ADJ

BRIGHT

GAMMA 1

GAMMA 2

FRP

SUB

BRIGHT R

SUB

BRIGHT B

CLIP

252627282930313233343536

2

CC

V

24

B OUT

23

B DC DET

22

G OUT

21

G DC DET

20

R OUT

19

R DC DET

18

17

16

VXO OUT

15

APC FILTER

14

VXO IN

HUE

13

G-Y

R-Y

Y/C

B-Y

MATRI

G GEN

P

N

X

Y

COMP

INT / EXT SW

REG3 REG2

HPF

Y/C

DL

EXT SYNC

COLOR

PAL SW

PAL ON

γ

γ INVDL

DEMOD

F/F

P

KILLER

N

BRIGHT

PHASE

SHIFT

P

IDENT

N

VREF

INV

N

P

V

EE

GND

VXO

APC

HUE

ACC DETACC

NT/PAL/ COLO R DEFFER

1 2 3 4 5 6 7 8 9 10 11 12

B-Y

TRAP

OUT

H FILTER

IDENT

VIDEO IN

C IN

FILTER

KILLER

COLO R

BURST OUT

R-Y

FIL TER

ACC F IL T ER

—2—

OUT

CHROMA

CXA1785AR

Pin Description (The pin voltage is VCC1 = 4.5 V)

Pin No. Symbol Pin voltage Equivalent circuit Description

1 TRAP 2.0V

CC1

V

Trap connection. Leave this pin open other than when composite video input is

1

selected.

2 H FILTER

OUT

3 VIDEO IN 2.25V

4 IDENT

FILTER

VCC1

3

VEE

V

EE

V

CC1

V

VCC1

4

EE

GND

Outputs the video signal to be input to the sync separation circuit.

2

GND

Composite video signal input (Y signal when using Y/C input and Y/color difference input). The standard input level is 0.5 VP-P (from sync tip to 100 % white).

GND

IDENT detection filter connection. Leave this pin open other than when PAL mode is selected.

5 C IN 2.5V

V

CC1

V

5

EE

VEE

—3—

GND

Chroma signal input when using Y/C input. Composite video signal input is supported when this pin is connected to GND. Leave this pin open when Y/color difference input. The standard input level is

GND

0.15 VP-P (burst).

Pin No. Symbol Pin voltage Equivalent circuit Description

6 COLOR

V

CC1

Color adjustment. The amplitude of color difference signal is adjusted when Y/color difference input.

6

EE

V

GND

CXA1785AR

7 BURST 3.2V

OUT

8 KILLER

FILTER

9 R–Y 1.9V

10 B–Y 1.9V

V

CC1

9

10

V

VCC1

VEE

V

EE

7

CC1

8

V

EE

GND

Burst cleaning coil is connected for PAL. Leave this pin open other than when PAL mode is selected.

Killer detection filter is connected. Leave this pin open other than when Y/color difference input is selected.

Color difference demodulation circuit inputs. Leave this pin open for NTSC. Color difference signal is input when Y/color difference input. In this case, input is pedestal clamped by using external coupling capacitor.

11 ACC

FILTER

VCC1

11

EE

V

ACC detection filter is connected. Leave this pin open for Y/color difference input.

—4—

Pin No. Symbol Pin voltage Equivalent circuit Description

12 CHROMA 2.3V

OUT

V

CC1

12

EE

V

GND

Color adjusted and burst taken out chroma signal is output.

CXA1785AR

13 HUE

14 VXO IN 3.9V

15 APC

FILTER

V

CC1

13

Color phase adjustment pin. Also doubles as the NTSC, PAL or Y/color difference switch. PAL is selected when this pin is connected to GND;

EE

V

GND

Y/color difference is selected when this pin is connected to Vcc1. VXO input.

CC1

V

Leave this pin open for Y/color difference input.

14

V

EE

GND

APC detection filter connection.

V

CC1

Leave this pin open for Y/color difference input.

16 VXO OUT 2.7V

17 GND

18 VEE

V

15

V

EE

16

V

CC1

EE

GND

VXO output. Leave this pin open for Y/color difference input.

GND

Ground.

Minimum electric potential connection.

—5—

Pin No. Symbol Pin voltage Equivalent circuit Description

19 R DC DET

V

CC1

Smoothing capacitor connection for the feedback circuit

21 G DC DET

23 B DC DET

19 21 23

of RGB output DC level control . Use a low-leakage capacitor because this pin has high impedance.

CXA1785AR

20 R OUT Vcc2+VEE

2

22 G OUT

24 B OUT

25 VCC2

26 CLIP 2.3V

V

VCC1

26

EE

VCC2

20 22 24

VEE

GND

RGB primary color signal output.

Power supply connection for RGB output. Sets the RGB output amplitude (black-black) clip level. This pin is preset internally.

27 SUB 2.2V

BRIGHT

R

28 SUB 2.2V

BRIGHT

B

29 FRP

GND

VCC1

27 28

VEE

VCC1

29

VEE

Fine adjustment for R and B signal brightness. Functions with the γ compensation curve. This pin is preset internally.

GND

Polarity reverse timing pulse input for RGB output. Reversed when low; nonreversed when high.

GND

—6—

Pin No. Symbol Pin voltage Equivalent circuit Description

30 GAMMA1

CC1

V

30

Adjusts voltage gain change point γ1.

Output

CXA1785AR

γ 1

31 GAMMA2 2.25V

32 BRIGHT

33 DL ADJ 1.2V

34 SUB 2.25V

CONTRAST

R

35 SUB 2.25V

CONTRAST

B

V

CC

31

V

1

EE

V

VCC1

33

VEE

CC1

34 35

EE

CC1

32

V

EE

GND

Adjusts voltage gain change point γ2 and the peak limiter that operates by Vw γ2 above γ2.This pin is preset internally.

Output

GND

Vwγ 2

RGB output brightness adjustment. Does not function with the gamma compensation curve.

Adjusts delay time of R and B output for G output. The delay time is adjusted by changing the resistance value between this pin and GND. The B output delay time is twice the R output delay time. Connecting this pin to VCC turns off the R output and B output delay circuits. Fine adjustment for R and B signal contrast. This pin is preset internally.

Input

Peak limiter

γ 2

Input

V

EE

GND

—7—

Pin No. Symbol Pin voltage Equivalent circuit Description

36 SYNC IN

VCC1

High level input when synchronized; low level at all other times. The rising edge of the

36

input pulse must precede the falling edge of the SYNC OUT pulse. For PAL, the internal flip flop switches at the rising edge

EE

V

37 SYNC OUT

Vcc1

GND

of the input pulse. Outputs the sync signal separated by the sync separation circuit. High level

37

when synchronized and at low level in all other cases. This pin is of an open collector output. The high level for the

VEE

GND

output should be VEE + 15 V or less.

38 SYNC SEP 1.8V

VCC1

Sync separation circuit input. Input the H FILTER output signal.

CXA1785AR

39 EXT B IN

40 EXT G IN

41 EXT R IN

42 CONTRAST

VCC1

39 40 41

VEE

VCC1

38

VEE

GND

External digital signal input. There are two threshold values: VTH1 (approximately

1.2 V) and VTH2 (approximately 2.2 V). When one of the RGB signals exceeds VTH1, all of the RGB outputs go to black level; when an input exceeds VTH2, only the corresponding output goes to white level. Adjusts RGB output contrast.

42

V

EE

GND

—8—

Pin No. Symbol Pin voltage Equivalent circuit Description

43 VCC1 44 F ADJ 1.2V

Power supply connection. Connect a resistance between this pin and GND; the outflow

V

CC1

current value adjusts the internal filters. Connect 18 kΩ for both NTSC and PAL. The following conditions apply to the resistance connected: Allowable difference in resistance: ±2 %

V

44

EE

GND

Temperature characteristics:

±200 ppm

45 CLAMP

CC1

V

Clamps the luminance signal pedestal level. Use a low-leakage capacitor because this pin has high

45

impedance.

CXA1785AR

46 AGC

FILTER

47 AGC OUT

48 PICTURE

V

CC1

V

46

EE

V

VCC1

48

47

EE

GND

Connects AGC detection filter of luminance signal.

GND

Outputs the voltage detected by the AGC detection circuit of luminance signal. When the AGC amplifier gain is high, the output voltage is high.

GNDVEE

Adjusts frequency response of luminance signal. Decreasing the voltage emphasizes contours.

V

EE

GND

—9—