--1--

E93701A79-TE

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.

Absolute Maximum Ratings (Ta=25 °C)

· Supply voltage

· Operating temperature

Topr

20 to +75

°C

· Storage temperature

Tstg

65 to +150

°C

· Allowable power dissipation

450

Operating Conditions

· Supply voltage

4.75

· Supply voltage range

4.5 to 5.25

Description

The CXA1812Q is an IC developed for processing

video I/O signals in VCRs. This IC has a built-in

video output circuit designed especially for use with

viewfinders (VF), making this IC optimal for use in

camcorders. In addition, both the video input

system and the viewfinder video output system

provide title insertion functions, making it possible to

insert characters and graphics into video signals.

Features

· Built-in video output circuit for use with viewfinders

(title insertion function (white or black character),

compatible with SY/C and composite video output)

· Built-in C system EE/PB switch

EE : Electric-Electric monitor mode

· Title insertion function (white or black character)

· C MUTE function for playback in PAL mode

(Outputs C signal used for generating the

composite video signal)

· Built-in switch for switching between the two input

systems, Y and C

· Built-in 75

driver for the two input systems, Y

and C

(with power saving function)

Structure

Bipolar silicon monolithic IC

S-terminal Compatible Video I/O

32 pin QFP (Plastic)

CXA1812Q

--2--

CXA1812Q

Block Diagram and Pin Configuration

BUFF

DDS1

MUTE1

MUTE2

MUTE3

CLAMP

DDS2

DRIV

I
V

YIN2

GND

CIN1

CIN2

Y/VSEL

YOUTGND

YOUT

YINVIN

VOB

COUT1

YIN

P.SAVE

EVFYIN

SEL1

YOUTV

I
N

/
V

I
N

--3--

CXA1812Q

Pin Description

Externally applied voltage

Symbol

Equivalent circuit

Description

No.

voltage

COUTGND

VREG

COUT2

CMUTE

COUT

SEL2

0 V

4 V

2.2 V

0 V

2.2 V

0 V

60µ

150µ

120µ

GND

20µ

150

GND

660µ

16k

1.2m

2.2V

.
3

GND

20µ

150

Chroma 75

driver GND.

4 V internal regular output.

Connect a decoupling capacitor.

Do not use for external bias.

Chroma signal output used for

generating a composite video signal.

Control input used for muting both the

chroma signals that are input to Pins 27

(CIN1) and 29 (CIN2) and pass through

the EE path, as well as the chroma

signal that is input from Pin 7 (CIN).

Low (0 to 0.8 V) : normal operation

High (2 V to V

) : mute

Chroma 75

driver output.

Control input used for switching

between the signals input to Pins 27

and 29 and the signal input to Pin 7.

Low (0 to 0.8 V) :

signal at Pin 7 is selected

High (2 V to V

) :

signals at Pins 27 and 29 are selected

314mVp-p

143mVp-p

1.256Vp-p

572mVp-p

Externally applied voltage

--4--

CXA1812Q

Symbol

Equivalent circuit

Description

No.

voltage

CIN

COUTV

YOUTV

SEL1

EVFYIN

P. SAVE

4.75 V

0 V

2.5 V

(Sync tip)

0 V

80µ

150 20p

2.2V

GND

1µ

50µ

1100

GND

72k

15k

20µ

150

GND

Video output chroma signal input.

Coupled by means of a capacitor within

the IC.

Inputting a signal of 0.3 V or less may

lead waveform distortion.

Chroma 75

driver power supply.

Y 75

driver power supply.

Control input used for switching the

signals that are input from Pins 11

(EVFYIN) and 13 (YIN).

Low (0 to 0.8 V) :

signal at Pin 13 is selected

High (2 V to V

) :

signal at Pin 11 is selected

Y signal input for viewfinder.

Coupled by means of a capacitor ; in

order to keep clamp error to a

minimum, keep the input impedance as

low as possible.

Control input for power saver. When in

power saving mode, the Y and C 75

drivers stop operating. The output of

Pin 31 (YOUT) and Pin 5 (COUT) goes

to high impedance.

Low (0 to 0.8 V) : normal operation

High (2 V to V

) : power saving mode

314mVp-p

143mVp-p

0.5Vp-p

2.5V

Same as for Pin 6.

Externally applied voltage

--5--

CXA1812Q

Symbol

Equivalent circuit

Description

No.

voltage

YIN

COUT1

VOB

YOUT1

VOW

2.5 V

(Sync tip)

4.75 V

2.2 V

0 V

1.8 V

(Sync tip)

0 V

20µ

150

GND

90µ

180µ

GND

250µ

Video output Y signal input.

Coupled by means of a capacitor; in

order to keep clamp error to a

minimum, keep the input impedance as

low as possible.

Power supply other than the 75

driver.

Video input chroma signal output.

Control input for black level insertion of

the Y signals input to Pins 23 (YIN1)

and 25 (YIN2). The chroma signals

input from Pins 27 and 29 are also

muted simultaneously.

Low (0 to 0.8 V) : normal operation

High (2 V to V

) : insertion mode

Video input Y signal output.

Control input for white level insertion of

the Y signals input to Pins 23 and 25.

The chroma signals input from Pins 27

and 29 are also muted simultaneously.

This pin takes precedence over the Pin

16 control signal.

Low (0 to 0.8V) : normal operation

High (2 V to Vcc) : insertion mode

0.5Vp-p

2.5V

314mVp-p

143mVp-p

0.5Vp-p

1.8V

Same as for Pin 3.

Same as for Pin 4.

Same as for Pin 11.

--6--

CXA1812Q

Externally applied voltage

Symbol

Equivalent circuit

Description

No.

voltage

EVFY/VOUT

VOW1

EVFCOUT

VOB1

1.8 V

(Sync tip)

0 V

2.2 V

0 V

180µ

360µ 800µ

16k

GND

2.1V

.
3

GND

2.2V

20k

200µ

100µ

300µ

Y and composite video signal output for

the viewfinder. A composite video

signal is output when Pin 28 (Y/VSEL)

is high.

Control input for white level insertion of

the Y and composite video signals for

the viewfinder (output from Pin 19).

The chroma signal for the viewfinder

output from Pin 21 (EVFCOUT) is also

muted simultaneously. This pin takes

precedence over the Pin 22 (VOB1)

control signal.

Low (0 to 0.8 V) : normal operation

High (2 V to V

) : insertion mode

Chroma signal output for the

viewfinder. When Pin 28 is high, the

output amplifier goes into power saving

mode and Pin 21 goes to high

impedance.

Control input for black level insertion of

the Y and composite video signals for

the viewfinder. The chroma signal for

the viewfinder is also muted.

Low (0 to 0.8 V) : normal operation

High (2 V to V

) : insertion mode

1.8V

1Vp-p

628mVp-p

286mVp-p

Same as for Pin 4.

Same as for Pin 6.

--7--

CXA1812Q

Externally applied voltage

Symbol

Equivalent circuit

Description

No.

voltage

YIN1

YIN2

INSEL

GND

CIN1

CIN2

Y/VSEL

YOUTGND

2.5 V

(Sync tip)

0 V

1100

GND

1µ

40µ

150

GND

20µ

Video input Y signal inputs. Coupled

by means of a capacitor; in order to

keep clamp error to a minimum, keep

the input impedance as low as

possible.

Control input for switching between

signals input from Pins 23 and 25 and

from Pins 27 and 29.

Low (0 to 0.8 V) :

signals at Pins 23 and 27 are selected

High (2 V to V

) :

signals at Pins 25 and 29 are selected

GND other than the 75

driver.

Video input chroma signal inputs.

Coupled by means of a capacitor within

the IC.

Inputting a signal of 0.3 V or less may

lead waveform distortion.

Control input for switching the output

signal format for Pin 19.

Pin 19 output

Pin 21 output

Low : Y signal

Chroma signal

High : Composite

High impedance

video signal

Low (0 to 0.8 V)

High (2 V to V

)

Y 75

driver GND.

0.5Vp-p

2.5V

314mVp-p

143mVp-p

Same as for Pin 7.

Same as for Pin 6.

--9--

CXA1812Q

Item

Bias voltage adjustment

Current consumption 1

Current consumption 2

Current consumption PS

VREG voltage

Gain

Frequency response

Secondary distortion

VOB1 level

VOW1 level

DDS1 cross talk

Input SW cross talk

Gain

Frequency response

Secondary distortion

Output D range

Gain

Frequency response

Secondary distortion

VOB2 level

VOW2 level

DDS2 cross talk

Input SW cross talk

Symbol

VADJ

ICC1

ICC2

ICCPS

VREG

G17

F17

HD17

VOB1

VOW1

G31

F31

HD31

V31

G19

F19

HD19

VOB2

VOW2

Input

pins

23, 25

11, 13

Measu

rement

point

VADJ

ICC

31A

SW conditions

ON)

Bias conditions (Unit : V)

E10

E12

E16

E18

E20

E22

E24

E28

4.75

0.8

2.0

0.8

4.75

0.8

2.0

0.8

2.0

0.8

4.75

0.8

4.75

0.8

2.0

0.8

Measurement conditions

Adjust VADJ pin to 2.85 V with RV

No signal

357 mVp-p, 300 kHz G (300 k)

357 mVp-p, 5 MHz G (5 M)/G (300 k)

357 mVp-p, 5 MHz V (10 M)/V (5 M)

500 mVp-p (Y100 %),

difference between input and Sync tip

500 mVp-p (Y100 %),

difference between input and Sync tip

357 mVp-p, 5 MHz G (CT)/G (5 M)

357 mVp-p, 300 kHz G (300 k)

357 mVp-p, 5 MHz G (5 M)/G (300 k)

357 mVp-p, 5 MHz V (10 M)/V (5 M)

Output amplitude for 679 mVp-p

(Y150 %) input

357 mVp-p, 300 kHz G (300 k)

357 mVp-p, 5 MHz G (5 M)/G (300 k)

357 mVp-p, 5 MHz V (10 M)/V (5 M)

500 mVp-p (Y100 %),

difference between input and Sync tip

500 mVp-p (Y100 %),

difference between input and Sync tip

357 mVp-p, 5 MHz G (CT)/G (5 M)

357 mVp-p, 5 MHz G (CT)/G ( 5M)

Min.

Typ.

Max.

Unit

16.0

25.0

35.0

15.0

24.0

34.0

9.5

16.0

22.5

3.90

4.05

4.20

0.5

160

180

200

390

410

430

5.5

6.0

6.5

0.75

0.25

1.20

1.34

Vp-p

5.5

6.0

6.5

0.5

320

360

400

780

820

860

Electrical Characteristics

(Ta=25

°
C, V

=4.75 V, refer to the electrical characteristics measurement circuit.)

No.

Y input

Y output

EVF Y output

--10--

CXA1812Q

Item

Gain

Frequency response 1

Frequency response 2

Frequency response 3

Secondary distortion

MUTE level

MUTE cross talk

Input SW cross talk

Gain

Frequency response 1

Frequency response 2

Frequency response 3

Secondary distortion

MUTE level

MUTE cross talk

Input SW cross talk

SEL2 SW cross talk

Gain

Frequency response 1

Frequency response 2

Frequency response 3

Secondary distortion

MUTE level

MUTE cross talk

Input SW cross talk

SEL2 SW cross talk

Symbol

G15A

15A

HD15A

M15A

15A

G5A

HD5A

M5A

G3A

HD3A

M3A

Input

pins

27, 29

Measu

rement

point

SW conditions

ON)

Bias conditions (Unit : V)

E10

E12

E16

E18

E20

E22

E24

E28

4.75

0.8

4.75

0.8

2.0

0.8

4.75

0.8

2.0

0.8

Measurement conditions

314 mVp-p, 3.58 MHz G (3.58 M)

314 mVp-p, 2.5 MHz G (2.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz G (4.43 M)/G (3.58 M)

314 mVp-p, 5.5 MHz G (5.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz V (8.86 M)/V (4.43 M)

DC differential when mute is off

314 mVp-p, 4.43 MHz G (CT)/G (4.43 M)

314 mVp-p, 3.58 MHz G (3.58 M)

314 mVp-p, 2.5 MHz G (2.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz G (4.43 M)/G (3.58 M)

314 mVp-p, 5.5 MHz G (5.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz V(8.86 M)/V (4.43 M)

DC differential when mute is off

314 mVp-p, 4.43 MHz G (CT)/G (4.43 M)

314 mVp-p, 4.43 MHz G(CT)/G (4.43 M)

314 mVp-p, 3.58 MHz G (3.58 M)

314 mVp-p, 2.5 MHz G (2.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz G (4.43 M)/G (3.58 M)

314 mVp-p, 5.5 MHz G (5.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz V(8.86 M)/V (4.43M)

DC differential when mute is off

314 mVp-p, 4.43 MHz G (CT)/G (4.43 M)

Min.

Typ.

Max.

Unit

0.8

0.3

0.2

0.5

5.2

5.7

6.2

0.5

0.8

0.3

0.2

0.5

No.

C input 1

C EE 1

C EE 2

--11--

CXA1812Q

Item

Gain

Frequency response 1

Frequency response 2

Frequency response 3

Secondary distortion

MUTE level

MUTE cross talk

Input SW cross talk

SEL2 SW cross talk

Gain

Frequency response 1

Frequency response 2

Frequency response 3

Secondary distortion

MUTE level

MUTE cross talk

Input SW cross talk

SEL2 SW cross talk

Y/V SW cross talk

Gain

Frequency response 1

Frequency response 2

Frequency response 3

Secondary distortion

MUTE level

MUTE cross talk

SEL2 SW cross talk

Symbol

G21A

21A

HD21A

M21A

21A

G19A

19A

HD19A

M19A

19A

G5B

HD5B

M5B

Input

pins

27, 29

Measu

rement

point

SW conditions

ON)

Bias conditions (Unit : V)

E10

E12

E16

E18

E20

E22

E24

E28

4.75

0.8

2.0

0.8

4.75

0.8

2.0

0.8

2.0

0.8

2.0

0.8

4.75

0.8

2.0

0.8

2.0

Measurement conditions

314 mVp-p, 3.58 MHz G (3.58 M)

314 mVp-p, 2.5 MHz G (2.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz G (4.43 M)/G (3.58 M)

314 mVp-p, 5.5 MHz G (5.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz V (8.86 M)/V (4.43 M)

DC differential when mute is off

314 mVp-p, 4.43 MHz G (CT)/G (4.43 M)

314 mVp-p, 3.58 MHz G (3.58 M)

314 mVp-p, 2.5 MHz G (2.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz G (4.43 M)/G (3.58 M)

314 mVp-p, 5.5 MHz G (5.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz V (8.86 M)/V (4.43 M)

DC differential when mute is off

314 mVp-p, 4.43 MHz G (CT)/G (4.43 M)

314 mVp-p, 3.58 MHz G (3.58 M)

314 mVp-p, 2.5 MHz G (2.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz G (4.43 M)/G (3.58 M)

314 mVp-p, 5.5 MHz G (5.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz V (8.86 M)/V (4.43 M)

DC differential when mute is off

314 mVp-p, 4.43 MHz G (CT)/G (4.43 M)

Min.

Typ.

Max.

Unit

5.2

5.7

6.2

0.5

5.2

5.7

6.2

0.5

5.2

5.7

6.2

0.5

No.

C EE EVF 1

C EE V 1

C output 1

--12--

CXA1812Q

Item

Gain

Frequency response 1

Frequency response 2

Frequency response 3

Secondary distortion

MUTE level

MUTE cross talk

SEL2 SW cross talk

Gain

Frequency response 1

Frequency response 2

Frequency response 3

Secondary distortion

MUTE level

MUTE cross talk

SEL2 SW cross talk

Gain

Frequency response 1

Frequency response 2

Frequency response 3

Secondary distortion

MUTE level

MUTE cross talk

SEL2 SW cross talk

Y/V SW cross talk

Symbol

G3B

HD3B

M3B

G21B

21B

HD21B

M21B

21B

G19B

19B

HD19B

M19B

19B

Input

pins

Measu

rement

point

SW conditions

ON)

Bias conditions (Unit : V)

E10

E12

E16

E18

E20

E22

E24

E28

4.75

0.8

2.0

0.8

2.0

4.75

0.8

2.0

0.8

4.75

0.8

2.0

0.8

2.0

0.8

Measurement conditions

314 mVp-p, 3.58 MHz G (3.58 M)

314 mVp-p, 2.5 MHz G (2.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz G (4.43 M)/G (3.58 M)

314 mVp-p, 5.5 MHz G (5.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz V (8.86 M)/V (4.43 M)

DC differential when mute is off

314 mVp-p, 4.43 MHz G (CT)/G (4.43 M)

314 mVp-p, 3.58 MHz G (3.58 M)

314 mVp-p, 2.5 MHz G (2.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz G (4.43 M)/G (3.58 M)

314 mVp-p, 5.5 MHz G (5.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz V (8.86 M)/V (4.43 M)

DC differential when mute is off

314 mVp-p, 4.43 MHz G (CT)/G (4.43 M)

314 mVp-p, 3.58 MHz G (3.58 M)

314 mVp-p, 2.5 MHz G (2.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz G (4.43 M)/G (3.58 M)

314 mVp-p, 5.5 MHz G (5.5 M)/G (3.58 M)

314 mVp-p, 4.43 MHz V (8.86 M)/V (4.43 M)

DC differential when mute is off

314 mVp-p, 4.43 MHz G (CT)/G (4.43 M)

Min.

Typ.

Max.

Unit

0.8

0.3

0.2

0.5

5.2

5.7

6.2

0.5

5.2

5.7

6.2

0.5

No.

100

C output 2

C EVF output 1

C EVF output 2

--13--

CXA1812Q

Item

Y input

C input

Symbol

15Y

21Y

17C

19C

31C

Input

pins

11, 13

23, 25

11, 13

23, 25

11, 13

23, 25

11, 13

23, 25

7, 27

Measu

rement

point

31A

SW conditions

ON)

Bias conditions (Unit : V)

E10

E12

E16

E18

E20

E22

E24

E28

4.75

0.8

2.0

0.8

2.0

0.8

Measurement conditions

357 mVp-p, 5 MHz G (CT)/G (4.43 M)

314 mVp-p, 4.43 MHz G (CT)/G (4.43 M)

Min.

Typ.

Max.

Unit

No.

101

102

103

104

105

106

107

Cross talk between Y and C (These measurement items are performed with the reference inputs.)

0.8 V for Pin 23 input; 2.0 V for Pin 25 input

With E16 and E18=0.8 V or 2.0 V, measure in all combination modes except for E16=E18=0.8 V

2.0 V for Pin 23 input; 0.8 V for Pin 25 input

0.8 V for Pin 13 input; 2.0 V for Pin 11 input

0.8 V for Y/C output; 2.0 V for V output

With E20 and E22=0.8 V or 2.0 V, measure in all combination modes except for E20=E22=0.8 V

2.0 V for Pin 13 input; 0.8 V for Pin 11 input

0.8 V for Pin 27 input; 2.0 V for Pin 29 input

2.0 V for Pin 27 input; 0.8 V for Pin 29 input

10.

With E4, E16 and E18=0.8 V or 2.0 V, measure in all combination modes except for E4=E16=E18=0.8 V

11.

With E4, E16, E18, E20 and E22=0.8 V or 2.0 V, measure in all combination modes except for E4=E16=E18=E20=E22=0.8 V

12.

With E4, E20 and E22=0.8 V or 2.0 V, measure in all combination modes except for E4=E20=E22=0.8 V

13.

2.0 V for Pin 11 input; 0.8 V for all others

14.

0.8 V for Pins 25 and 29 input; 2.0 V for all others

15.

0.8 V for Pin 7 input; 2.0 V for all others

--14--

CXA1812Q

Electrical Characteristics Measurement Circuit

.
0

I
V

.
2

I
C

.
0

--15--

CXA1812Q

Application Circuit

I
V

.
0

.
4

.
0

(
T

:

4

.
7

)

.
5

-
p

.
5

-
p

.
5

-
p

t
r
o

l

B

l
o

i
n

i
g

r
o

i
n

l
o

i
e

f
i
n

r

S

i
g

r
o

i
n

l
o

r
a

i
g

r
o

i
n

l
o

.
4

.
0

.
2

Application circuits shown are typical examples illustrating the operation of the devices. Sony cannot assume responsibility fo

any problems arising out of the use of these circuits or for any infringement of third party patent and other right due to same

--16--

CXA1812Q

Description of Operation
(Refer to the Pin Description for details on the standard I/O signal levels and the control logic.)

· Video Input System

The Y signals input to Pins 23 (YIN1) and 25 (YIN2) are clamped by the respective sync tips, and one of the
signals is selected by the control signal input to Pin 24 (INSEL). Titles are inserted by the control signals input
to Pins 16 (VOB) and 18 (VOW), and after passing through the buffer the signal is output from Pin 17
(YOUT1). Regarding the title insertion levels, the white level is approximately 75IRE and the black level is
approximately 10IRE. Title insertion is described in detail later.
Just as with the Y signals, one of the C signals input to Pins 27 (CIN1) and 29 (CIN2) is selected by the control
signal at Pin 24. The signal is muted to the chroma center level by the control signals at Pins 16 and 18, and
after being branched to EE output, the signal passes through the buffer and is output from Pin 15 (COUT1).

· Video Output System

INSEL

VOB

VOW

YIN1

YIN2

CIN1

CIN2

r
o

t
e

l

c

r
a

i
g

l

p

r
o

i
n

l
o

C input system

Y input system

CLAMP

DDS 1

BUFF

MUTE 1

YOUT1

COUT1

To video signal
processing block

To C output system (EE)
and VFC output system

YIN

CIN

DRIV

BUFF

DRIV

CLAMP

MUTE 3

From the video
signal processing
block

Y output system

From C input system(EE)

C output system

To VFY output system

To VFC output system

SEL2

CMUTE

P.SAVE

COUT2

COUT

YOUT

0.01µ

220µ

2.2µ

YINVIN

330

External
video
output

To composite
video signal
generation circuit

--17--

CXA1812Q

The Y signal input to Pin 13 (YIN) is clamped by the sync tip and is then branched to the Y output system and
the VFY output system. The signal sent to the Y output system passes through the 75

driver (gain=12 dB)

and is then output from Pin 31 (YOUT).
Either the C signal input from Pin 7 (CIN) or the C signal for EE output that was branched from the C input
system is selected by the control signal input to Pin 6 (SEL2). After the signal is muted to the chroma center
level by the control signal input to Pin 4 (CMUTE), the signal is branched to the VFC output system and is also
passed through the 75

driver (gain=12 dB), after which it is output from Pin 5 (COUT). The signal is also

output from Pin 3 (COUT2) for composite video signal generation. The role of Pin 3 is explained in more detail
later.
When Pin 12 (P.SAVE) is set high, it is power saving mode. At this time, the Y and C 75

drivers cease

functioning and the outputs go to high impedance.

· VF Video Output System

The Y signals input to Pins 13 and 11 (EVFYIN) are clamped by the respective sync tips, and one of the
signals is selected by the control signal input to Pin 10 (SEL1). When the video signal required for the
viewfinder is different from the signal input to Pin 13, the necessary signal is input from Pin 11. Titles are
inserted by the control signals input to Pins 22 (VOB1) and 20 (VOW1). Just as in the video input system,
regarding the title insertion levels, the white level is approximately 75IRE and the black level is approximately
10IRE. Either this Y signal or the post-Y/C MIX composite video signal is selected by the control signal input
to Pin 28 (Y/VSEL), and then the signal passes through the 12 dB amplifier and is output from Pin 19
(EVFY/VOUT). When Pin 28 is high, the post-Y/C MIX composite video signal is selected. At the same time,
the 6 dB amplifier (for C output) stops functioning in order to reduce the amount of current consumption. At
this time, the output from Pin 21 (EVFCOUT) goes to high impedance.
The C signal for the viewfinder that was branched from the C output system is muted to the chroma center
level by the control signals input to Pins 22 and 20. This signal is input to the Y/C MIX circuit in order to
generate the composite video signal for the viewfinder; the signal is also passed through the 6 dB amplifier and
is output from Pin 21.

EVFYIN

YIN

CMUTE

SEL2

CIN

EVFY/VOUT

EVFCOUT

To C output system

To Y output system

From C input system (EE)

To VF block

CLAMP

DDS 2

MUTE 2

MUTE 3

12dB

6dB

SEL1

VOB1

VOW1

Y/VSEL

--18--

CXA1812Q

· Title Insertion Function (Timing Relationships)

When VOW/VOW1 is high, the Y signal
replaces from the pedestal level to an
electric potential of 75IRE (white character);
when VOB/VOB1 is high, the Y signal
replaces from the pedestal level to an
electric potential of 10IRE (black character).
The C signal replaces to the chroma center
electric potential when VOW/VOW1 or
VOB/VOB1/CMUTE is high.
Because VOW/VOW1 have precedence,
VOW/VOW1 going high results in the
insertion of white character even if
VOB/VOB1 is high. If the settings are as
depicted in the diagram at right, white
character can be bordered with black.

· Relationship between Signal Flow and the Title Insertion function, and the Role of Pin 3

Title insertion 2 is performed by a Y/C main
signal processing IC. Although no problem
arises in NTSC system, in the case of PAL
system, because it is necessary to connect a
color spectrum compensation IC with a delay
element between the Y/C main signal
processing IC and the CXA1812Q, if the title
is inserted in the Y/C main signal processing
IC, a temporal deviation occurs in the title
insertion position for Y and C. This problem
is resolved by using MUTE 3 in the C system
only. In addition, because a C signal
processed with MUTE 3 and with no
temporal deviation is output from Pin 3, the
composite video signal can be obtained by
mixing this signal with the Y signal.

100 IRE

140 IRE

Bolder
section

Y signal

VOW
VOW1

VOB
VOB1
CMUTE

C signal

10 IRE

75 IRE

Y input

C input

Y output

VF output

C output

CXA1812Q

MUTE 2

DDS 2

MUTE 1

DDS 1

MUTE 3

Title insertion 1

Includes delay element

Color spectrum
compensation IC
(required in PAL
system)

DDS

MUTE

REC
output

PB
input

Title
insertion 2

Pin 3

Composite (V) output

Title insertion 3

Y/C main signal processing IC

Title insertion 1

Title insertion 2

Title insertion 3

REC

output

Y, C, V

output

--19--

CXA1812Q

Notes on Operation

· Cross talk may become severe, depending on the power supply and the ground connections, and on the

substrate pattern. The power supply and ground connections should be wired so that impedance is as low

as possible, and the signal lines should be located away from other lines.

· The power supply pins should be decoupled as closely as possible to the IC. Because Pin 14 (V

) is the

main power supply for this IC, inadequate decoupling can result in a worsening of characteristics such as

distortion and cross talk. Pins 8 (COUTV

) and 9 (YOUTV

) are power supplies for the output stage of

the 75

drivers, and inadequate decoupling can result in oscillation.

· If more than the necessary capacitance is connected to the output pins (Pins 3, 5, 15, 17, 19, 21, and 31),

oscillation may result. Wiring should be kept as short as possible.

· The frequency response of the Y 75

driver can be controlled by external elements.

The frequency response is raised if capacitance is connected to Pin 32 (YINVIN) versus GND.

The frequency response is attenuated in the high frequency if capacitance is connected between Pin 31

(YOUT) and Pin 32.

· When Pin 6 (SEL2) is low, Pin 7 (CIN) and Pin 5 (COUT) have an input/output relationship, so that if more

than the necessary amount of capacitance is connected between these two pins, a loop may be formed and

oscillation may easily result. When designing the board, make sure that there is no parasitic capacitance

between Pins 7 and 5.

· Pins 7 (CIN), 27 (CIN1), and 29 (CIN2) are coupled within the IC. If a signal of 0.3 V or less is input, a

protective element may cause waveform distortion. When inputting a signal of 0.3 V or less, it is

recommended that a suitable DC bias be applied to the input signal.

--20--

CXA1812Q

Ambient temperature vs. Current consumption

-
C

r
r
e

t

c

t
i
o

(
m

)

100

Ambient temperature vs. VREG voltage

l
t
a

(
V

)

100

Ta-Ambient temperature (°C)

4.080

4.070

4.060

4.050

Frequency response (Y output system)

i
n

(
d

)

Frequency (Hz)

i
s

t
o

r
t
i
o

(
d

)

100

200

300

400

500

600

Input amplitude (mVp-p)

100k

10M

100M

Vin=357mVp-p

Frequency response (CEE system)

i
n

(
d

)

Frequency (Hz)

100k

10M

100M

Vin=314mVp-p

Input amplitude vs. Second distortion
(Y output system)

i
s

t
o

r
t
i
o

(
d

)

100

200

300

400

500

600

Input amplitude (mVp-p)

Input amplitude vs. Second distortion
(CEE system)

--21--

CXA1812Q

r
o

t
a

l
k

(
d

)

r
o

t
a

l
k

(
d

)

r
o

t
a

l
k

(
d

)

r
o

t
a

l
k

(
d

)

100

200

300

400

500

600

Input amplitude (mVp-p)

Input amplitude vs. Cross talk (EVF output system)
<SEL1 SW cross talk>

100

200

300

400

500

600

Input amplitude (mVp-p)

Frequency vs. Cross talk (EVFY output system)
<SEL1 SW cross talk>

r
y

i
s

t
o

r
t
i
o

(
d

)

10M

Frequency (Hz)

Input amplitude vs. Cross talk (CEE system)
<SEL2 SW cross talk>

Vin=357mVp-p

Frequency vs. Secondary distortion (Y output system)

10M

Frequency (Hz)

Vin=357mVp-p

Frequency vs. Cross talk (CEE system)
<SEL2 SW cross talk>

10M

Frequency (Hz)

Vin=314mVp-p

r
y

i
s

t
o

r
t
i
o

(
d

)

10M

Frequency (Hz)

Vin=314mVp-p

Frequency vs. Secondary distortion (CEE system)

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: CXA1812

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: CXA1812