Datasheet BA7232FS Datasheet (ROHM)

1

Multimedia ICs

Color TV Signal Encoder

BA7232FS

The BA7232FS converts analog RGB signals into color TV signals in the NTSC and PAL formats. From inputs of
analog RGB signals, a composite synch signal, burst pulses and a color carrier, this IC generates a color TV signal,
and can be adapted for either NTSC or PAL standards, which are selected externally. When set to PAL, the
BA7232FS changes chroma phase according to the burst flag pulses.
The chroma signals and luminosity signals can be combined into a color TV signal or output separately, making this
IC suitable for S pins. Also, this IC comes with an output pin for the analog RGB signal. Each output has a built-in
75Ω driver.

•

Applications

TV peripherals

•

Features

1) Can be adapted for NTSC and PAL formats.

2) Internal flip-flop for PAL phase switching.

3) Separate Y / C output pins.

4) Analog RGB signal output pins.

5) Internal 75Ω driver. (outputs color TV signals, lumi­nosity signals, chroma signals and analog RGB sig­nals)

6) Adaptable for color subcarrier pulse input.

•

Block diagram

1BIN

2GIN

3RIN

4VCC1

5SYNCIN

6BFPIN

7NT / PAL

8SCIN

9GND1

10COUT

20 BOUT

19 GOUT

18 ROUT

17 VCC2

16 SYNCOUT

15 YOUT

14 N.C.

13 VOUT

12 N.C.

11 GND2

GND

GND

FILTER

F • F

Y / C

MIX

SYNC

MIX

PHASE

GEN.

BURST

GEN.

SYNC

V

CC

VCC

B - Y MOD.

R - Y MOD.

BFP

BFP

BFP

MATRIX

SYNC

75Ω

75Ω

75Ω

75Ω

75Ω

75Ω

CLAMP

CLAMP

CLAMP

2

Multimedia ICs BA7232FS

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Pin descriptions

Pin name
1 BIN Analog B signal input
2 GIN Analog G signal input
3 RIN Analog R signal input
4
5 SYNCIN
6 BFPIN

7 NT / PAL
8 SCIN Color subcarrier input

9 GND1 Ground for all drivers other than the 75Ω driver

10 COUT Chroma signal output. Internal 75Ω driver.
11 GND2 Ground for the 75Ω driver
12 N.C. This pin is not connected inside the IC.
13 VOUT Color TV signal output. Internal 75Ω driver.
14 N.C. This pin is not connected inside the IC.
15 YOUT Luminance signal output. Internal 75Ω driver.
16 SYNCOUT Composite synchronization signal output
17
18 ROUT Analog R signal output. Internal 75Ω driver
19 GOUT Analog G signal output. Internal 75Ω driver.
20 BOUT Analog B signal output. Internal 75Ω driver.

Pin No. Function

V

CC2

Power supply pin for all drivers other than the 75Ω driver

Burst flag pulse input (negative logic)

Composite synchronization signal input (negative logic)

Power supply pin for all drivers other than the 75Ω driver

Selecting the type of color TV signal output
(high = NTSC, low = PAL)

V

CC1

•

Absolute maximum ratings (Ta = 25°C)

•

Recommended operating conditions (Ta = 25°C)

Parameter Symbol Limits Unit

Power supply voltage

V

CC

7V

Power dissipation

Pd

mW
Operating temperature Topr °C
Storage temperature Tstg °C

750

∗

∗

Reduced by 7.5mW for each increase in Ta of 1°C over 25°C.

When mounted on a 70 × 70 × 1.6mm glass epoxy board.

– 20 ~ + 70
– 55 ~ + 125

Parameter Symbol Limits Unit

Power supply voltage

V

CC

4.5 ~ 5.5 V

RIN input level

υ

RI

0 ~ 0.7

V

P-P

GIN input level

υ

GI

0 ~ 0.7

V

P-P

BIN input level

υ

BI

0 ~ 0.7

V

P-P

SCIN input level

υ

SC

0.45 ~ 0.6

V

P-P

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Multimedia ICs BA7232FS

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Electrical characteristics (unless otherwise noted, Ta = 25°C, VCC = 5V, XTAL = 3.58MHz)

V

IL

——

0.8 V

V

IH

2.2

——

V

Input impedance

Z

I

8 13.5

—

k

Ω

Parameter Symbol Min. Typ. Max. Unit Conditions

Current dissipation I

CC

33.0 48.0 63.0 mA

YOUT
VOUT

Luminance level

υ

L

0.63 0.70 0.77 V

P-PυRI

=

υGI =

υBI = 0.7V

P-P

Luminance level R

υ

L(R)

0.19 0.21 0.23 V

P-P

Luminance level G

υ

L(G)

0.37 0.41 0.45 V

P-P

Luminance level B

υ

L(B)

0.07 0.08 0.09 V

P-P

Synchronization level

υ

S

0.27 0.30 0.33 V

P-P

R

S/L

0.38 0.43 0.48

R

YO

=

υS /

υ

L

COUT
VOUT

R / burst level ratio R

R/BU

2.84 3.16 3.48

G / burst level ratio R

G/BU

2.65 2.95 3.25

B / burst level ratio R

B/BU

2.01 2.24 2.47

R phase

θ

R

94 104 114 deg

G phase

θ

G

231 241 251 deg

B phase

θ

B

337 347 357 deg

Burst level

υ

BU

0.26 0.29 0.32 V

P-P

Carrier leak

υ

CL

—

—

—

—

—

—

—

—

—
—

—
—
—
—
—

—

—

—

—

—

35 mV

P-P

PAL burst phase

θBU+ 125 135 145 deg
θBU– 215 225 235 deg

PAL burst level ratio R

BU

0.9 1.0 1.1

SYNCOUT

2.00 2.50 5.00 V
0

——

—

0.40 V

υ

RO

0.63 0.70 0.77 V

P-PυRI

= 0.7V

P-P

υ

GO

0.63 0.70 0.77 V

P-PυGI

= 0.7V

P-P

υ

BO

0.63 0.70 0.77 V

P-PυBI

= 0.7V

P-P

V

YO

1.60 2.00 2.40 V

V

CO

2.20 2.60 3.00 V

V

VO

1.75 2.15 V

V

RO

1.25 1.65 2.05 V

V

GO

1.25 1.65 2.05 V

V

BO

1.25 1.65 2.05 V

Synchronization /
luminance level ratio

Input voltage "L" level

Input voltage "H" level

SYNC, BFP, NT / PAL

SYNC, BFP, NT / PAL

SYNC, BFP, NT / PAL

1.35

YOUT DC voltage
COUT DC voltage
VOUT DC voltage
ROUT DC voltage
GOUT DC voltage
BOUT DC voltage

Output level (HIGH)

Output level (LOW)
ROUT
GOUT
BOUT

output level
output level
output level

υRI = 0.7V

P-P

∗

1

υGI = 0.7V

P-P

∗

1

υBI = 0.7V

P-P

∗

1

υRI = 0.7V

P-P

∗

1

υGI = 0.7V

P-P

∗

1

υBI = 0.7V

P-P

∗

1

SW1 = 2

∗

1

SW1 = 2

∗

1

SW1 = 2

∗

1

∗

1 Guaranteed performance.

∗

2 Measured 3.5 µs after burst with a 3.58 MHz BPF.

∗

3 Measured with a 3.58 MHz BPF.

䊊 Not designed for radiation resistance.

∗

1

∗

1

∗

1

∗

3

∗

2

4

Multimedia ICs BA7232FS

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Measurement circuit

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

GND

GND

FILTER

F • F

Y / C

MIX

SYNC

MIX

PHASE

GEN.

BURST

GEN.

SYNC

V

CC

VCC

B - Y MOD.

R - Y MOD.

BFP

BFP

BFP

MATRIX

SYNC

CLAMP

CLAMP

CLAMP

0.47µ

0.1

µ

75

75

COUT
measurement point

560

4.7k

Color subcarrier

V

CC

Burst flag pulse

(BFP)

Composite synch

V

CC

0.1

µ

0.1

µ

0.1

µ

RIN input

GIN input

BIN input

75

75

220

µ

+

BOUT
measurement point

75

75

220

µ

+

GOUT
measurement point

75

75

220

µ

+

ROUT
measurement point

75

75

2K

220

µ

+

YOUT
measurement point

75

75

220

µ

+

VOUT
measurement point

VCC

SYNCOUT
measurement point

SW1

1

2

75Ω

75

Ω

75

Ω

75

Ω

75

Ω

75

Ω

5

Multimedia ICs BA7232FS

NT / PAL

BFP

Chroma phases

burst

B - Y

R - Y

burst

burst

B - Y B - Y

R - Y

R - Y

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Circuit operation
(1) SYNCIN is for composite synch input. During low
input, the synchronization signal is output to YOUT,
VOUT and SYNCOUT.
(2) BFP is for burst flag pulse input. During low input,
the burst signal is output to pins CO and VO. When the
IC is set to PAL, it is this signal that directs the phase
inversion of the chroma signals. This signal also con­trols the timing of the pedestal clamps of RIN, GIN and
BIN. During low input, the pedestal levels of RIN, GIN
and BIN are kept constant by charging an attached
capacitor.
(3) NT / PAL is the NTSC / PAL selector pin, and con­nects to V

CC when set to NTSC and to GND when set

to PAL.

(4) SCIN is for color subcarrier input. Set input to a
pulse wave or sine wave (3.579545MHz for NTSC and

4.433619MHz for PAL).
(5) COUT and YOUT are for output of chroma signals
and luminosity signals, respectively. Because the chro­ma signal and luminosity signals can be output sepa­rately, the IC can be adapted for S pins. Each has a
75Ω driver.
(6) VOUT is for color TV signal output, and has an
internal 75Ω driver.
(7) ROUT, GOUT and BOUT are for analog RGB sig­nal output, and have an internal 75Ω driver.

The relationship between chroma phase and burst phase during PAL processing is as follows.

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Multimedia ICs BA7232FS

1

2

3

4

5

6

7

8

9

10

20

19

18

17

16

15

14

13

12

11

GND

GND

FILTER

F • F

PHASE

GEN.

BURST

GEN.

SYNC

V

CC

VCC

B - Y MOD.

R - Y MOD.

BFP

BFP

BFP

MATRIX

SYNC

CLAMP

CLAMP

CLAMP

0.1µ

560

4.7k

Color subcarrier

V

CC

Burst flag pulse

(BFP)

Composite synch

V

CC

0.1µ

0.1µ

0.1µ

75

220µ

+

Color TV
signal output

VCC

Composite synch output

Analog B signal

Analog G signal

Analog R signal

Y / C

MIX

SYNC

MIX

75Ω

75Ω

75Ω

75Ω

75Ω

75Ω

SSOP - A20

11

10

20

1

0.11

7.8 ± 0.3

5.4 ± 0.2

8.7 ± 0.2

0.15 ± 0.1

0.36 ± 0.10.8

1.8 ± 0.1

0.3Min.

0.15

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Application example (NTSC color TV signals)

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External dimensions (Units: mm)

•

Operation notes
(1) Input impedance at the input terminals should be as
low as possible as the analog RGB signal is clamped
there.
(2) The color subcarrier should have a duty of 50%.
Duty fluctuation will affect chroma phase. Resistance­splitting input is used in the "Application example" to
accommodate 5V

P-P CMOS input. For other types of

input, adjust to 0.5V

P-P at SCIN.

(3) Composite synch and burst flag pulse inputs should
conform to their respective standards, as improper tim­ing between them can prevent the TV from displaying
color images. For input, use the TTL level and an
impedance of 8kΩ.