Multimedia ICs
Color TV signal encoder
BA7242F
The BA7242F is an IC which converts analog RGB signals to NTSC and PAL color TV signals. In addition to com-
posite output, luminance output, chrominance output, and analog RGB output are available. Each type of output is
equipped with an internal 75Ω driver.
•
Applicationsdevices
TV peripheral
•
Features both NTSC and PAL systems.
1) Supports
2) Internal flip-flop circuit for PAL common mode
switching
3) Equipped with Y / C separated output pin.
4) Internal 75Ω driver
5) Supports subcarrier pulse for color input
•
Block diagram
SYNC
BIN
1
CLAMP
MATRIX
BFP
GIN
2
CLAMP
BFP
RIN
3
CLAMP
BFP
B-Y
MOD
V
CC
1
4
GND
V
CC
11
GND2
SYNC
MIX
V
CC
14
V
CC
2
13
Y
OUT
Y/C
MIX
12
V
OUT
SYNC
5
CHROMA
GEN
SYNC
10
C
OUT
BURST
FLAG
R-Y
MOD
BFP
6
F•F
9
NT / PAL
NT / PAL
GND
NT / PAL
FILTER
PHASE
GEN
GND1
7
8
SCIN
1
Multimedia ICs
BA7242F
•
Absolute maximum ratings (Ta = 25°C)
Parameter
Power supply voltage
Power dissipation
Operating temperature
Storage temperature
Symbol
V
CC
Pd
Topr
Tstg
Limits
7
450
∗
– 20 ~ + 70
– 55 ~ + 125
Unit
V
mW
°C
°C
∗
Reduced by 4.5mW for each increase in Ta of 1°C over 25°C.
(When mounted on a 70mm
×
70mm
×
1.6mm glass epoxy board.)
•
Recommended operating conditions (Ta = 25°C)
Parameter
Power supply voltage
RIN input level
GIN input level
BIN input level
SCIN input level
Symbol
V
CC
υ
RI
υ
GI
υ
BI
υ
SC
Limits
4.5 ~ 5.5
0 ~ 0.7
0 ~ 0.7
0 ~ 0.7
0.45 ~ 0.60
Unit
V
V
P–P
V
P–P
V
P–P
V
P–P
•
Pin descriptions
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Pin name
BIN
GIN
RIN
V
CC
1
SYNC
BFP
GND1
SCIN
NT / PAL
C
OUT
GND2
V
OUT
Y
OUT
V
CC
2
Function
Input for analog B signal. Operate with low impedance.
Input for analog G signal. Operate with low impedance.
Input for analog R signal. Operate with low impedance.
V
CC
for all except 75Ω driver.
Input for composite SYNC signal. Outputs SYNC signal to VOUT and YOUT pins
when input is LOW.
Input for burst timing signal. Simultaneously performs the burst output and initiates
the pedestal clamp for the RIN, GIN, and BIN input signals when input is LOW.
GND for all except 75Ω driver.
3.58MHz or 4.43MHz pulse signal input.
Video signal output mode setting. HIGH level = NTSC, LOW level = PAL.
Chrominance signal output. Internal 75Ω driver.
GND for 75Ω driver.
Composite video signal output. Internal 75Ω driver.
Luminance signal output. Internal 75Ω driver.
V
CC
for 75Ω driver.
2
Multimedia ICs
BA7242F
CC
•
Electrical characteristics (unless otherwise noted, Ta = 25°C, V
Parameter
Current consumption
Luminance level
Luminance level R
YOUT
VOUT
Luminance level G
Luminance level B
Synchronization level
Synchronization /
luminance level ratio
Red / burst level ratio
Green / burst level ratio
Blue / burst level ratio
Red phase
Green phase
COUT
VOUT
Blue phase
Burst level
Carrier leak
PAL burst phase
PAL burst ratio
YOUT DC voltage
COUT DC voltage
VOUT DC Voltage
High level input voltage
SYNC, BFP, NT / PAL
Low level input voltage
SYNC, BFP, NT / PAL
Input current during high
SYNC, BFP, NT / PAL
Input current during low
SYNC, BFP, NT / PAL
Symbol
I
CC
υ
L
υ
L(R)
υ
L(G)
υ
L(B)
υ
S
R
S/L
R
R / BU
R
G / BU
R
B / BU
θ
R
θ
G
θ
B
υ
BU
υ
CL
θ
BU +
θ
BU –
R
BU
V
YO
V
CO
V
VO
V
IH
V
IL
V
IH
V
IL
Min.
23
0.63
0.19
0.37
0.07
0.27
0.38
2.84
2.65
2.01
94
231
337
0.26
—
125
215
0.9
1.60
2.20
1.35
2.0
—
—
—
Typ.
34
0.70
0.21
0.41
0.08
0.30
0.43
3.16
2.95
2.24
104
241
347
0.29
—
135
225
1.0
2.00
2.60
1.75
—
—
—
—
= 5V, SCIN = 3.579545MHz, NT / PAL = 5V)
Unit
mA
V
P-P
V
P-P
V
P-P
V
P-P
V
P-P
—
—
—
—
deg
deg
deg
V
P-P
mV
P-P
deg
deg
—
V
V
V
V
V
µA
µA
With 5V applied
With 0V applied
R
YO
=
υ
YS
/
υ
YL
υ
RI
= 0.7V
P-P
∗
2
υ
GI
= 0.7V
P-P
∗
2
υ
BI
= 0.7V
P-P
∗
2
∗
2
∗
2
∗
2
∗
4
∗
3
Max.
45
0.77
0.23
0.45
0.09
0.33
0.48
3.48
3.25
2.47
114
251
357
0.32
35
145
235
1.1
2.40
3.00
2.15
—
0.8
300
200
Conditions
υ
RI
=
υ
GI
=
υ
BI
= 0.7V
P-P
υ
RI
= 0.7V
P-P
∗
2
υ
GI
= 0.7V
P-P
∗
2
υ
BI
= 0.7V
P-P
∗
2
NT / PAL = 0V
∗
2
NT / PAL = 0V
∗
2
NT / PAL = 0V
∗
2
∗
2 Guaranteed design with these parameters
∗
3 Measured using a 3.58MHz BPF for 3.5µs after the burst.
∗
4 Measured using a 3.58MHz BPF.
Not designed for radiation resistance
3
Multimedia ICs
BA7242F
•
Measurement circuit
SYNC
0.1µ
BIN input
1
CLAMP
SYNC
MIX
V
CC
V
CC
14
0.1µ
GIN input
2
MATRIX
BFP
CLAMP
75
13
220µ
75
75
12
220µ
75
YOUT
measurement point
Y/C
MIX
0.1µ
RIN input
3
BFP
BFP
CLAMP
VOUT
measurement point
GND
V
CC
V
CC
B-Y
MOD
4
11
CHROMA
GEN
SYNC
75
10
0.47µ
75
Vcc
9
NT / PAL
COUT
measurement point
Composite SYNC
5
BURST
FLAG
R-Y
MOD
Burst flag pulse
(BFP)
6
F•F
NT / PAL
GND
0.1µ
8
560
4.7k
Color subcarrier
•
Operation description is input to the SYNCIN pin.
(1) The composite SYNC
During Low level input, the SYNC signal is output to
the YOUT, VOUT, and SYNCOUT pins.
(2) The burst flag pulse is input to the BFPIN pin.
During Low level input, the burst signal is output to the
COUT and VOUT pins. For PAL, the phase inversion of
the chroma signal occurs according to this signal.
Furthermore, this signal also acts as the timing for the
pedestal clamp for the RIN, GIN, and BIN pins. By
using an external condenser for charging during Low
level input, the pedestal levels for the RIN, GIN, and
BIN pins are maintained at a uniform level.
(3) The NT / PAL pin is for selecting either NTSC or
PHASE
GEN
7
PAL. For NTSC, this pin is connected to V
CC
and for
PAL, this pin is connected to GND.
(4) The SCIN pin is the color subcarrier input pin. Input
either a pulse wave or a sine wave of frequency
3.579545MHz for NTSC or of frequency 4.433619MHz
for PAL.
(5) The COUT pin is the output pin for the chroma sig-
nal, and the YOUT pin is the output pin for the lumi-
nance signal. This is compatible with the S pin because
the chroma signal and the luminance signal can be out-
put separately. Both pins have internal 75Ω drivers.
(6) The VOUT pin is the output pin for a color TV signal
and has an internal 75Ω driver.
4
FILTER
Multimedia ICs
BA7242F
•
Application example (When using NTSC color TV signal)
0.1µ
Analog B signal
1
CLAMP
SYNC
MIX
SYNC
V
CC
V
CC
14
0.1µ
Analog G signal
2
MATRIX
BFP
CLAMP
13
Y/C
MIX
0.1µ
Analog R signal
3
BFP
BFP
CLAMP
12
+
220µ
75
Color TV signal output
B-Y
MOD
4
GND
V
CC
V
CC
11
Composite SYNC
5
CHROMA
GEN
SYNC
10
BURST
FLAG
R-Y
MOD
Burst flag pulse
(BFP)
6
F•F
V
CC
9
NT / PAL
PHASE
GEN
FILTER
7
NT / PAL
0.1µ
8
560
4.7k
Color subcarrier
•
Operation notesRGB signals perform clamping at the
(1) Since analog
input pin, input them with a low impedance.
(2) Input a signal of duty 50% for the color subcarrier. If
the duty fluctuates, it will affect the chroma phase.
Furthermore, for the application example, a voltage-
dividing resistor is assumed for the CMOS input of 5V
P-P
.
For other input formats, regulate the SCIN pin for
0.5V
P-P
.
(3) Input the composite SYNC and burst flag pulse
according to the standard value. If the timing is off, the
TV receiver may not show any color. As well, set the
input level the same as the TTL level. The input imped-
ance is 8kΩ.
GND
•
External dimensions (Units: mm)
8.7
±
0.2
14
6.2
±
0.3
4.4
±
0.2
8
1.5
±
0.1
1
7
0.11
1.27
0.4
±
0.1
0.3Min.
0.15
SOP14
0.15
±
0.1
5
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