BH7240 Rohm, BH7240 Datasheet - Page 9

• Manufacturer Part Number: BH7240
• Description: Color TV signal encoder
• Manufacturer: Rohm

•
(1) The DAC system clock is input to the VCLK pin.
RGB data is taken into the IC at the rising edge of this
clock.
(2) The subcarrier is input to the SCIN pin. There is an
internal input capacitor in the IC, so no external DC
cutoff is necessary. Also, the input level supports a
range of 0.5 to 5V
nance phase, distortion-free sine waves or pulses with
a duty of 50% should be input in a range which does
not exceed the V
(3) Composite SYNC signals are input to SYNCIN.
When the input level is low, SYNC signals are output to
the composite output (V
(Y
DAC is carried out at this timing. To prevent erroneous
clamping, RGB data should be set to 00 input during
the SYNC interval.
(4) Burst timing and the chrominance phase reversal
timing when PAL is used are generated by SYNC sig-
nals and subcarriers. For this reason, signals input as
SYNC signals and subcarriers should be in confor-
mance with standards.
•
Multimedia ICs
Circuit operation
External dimensions (Units: mm)
OUT
), and DC clamping of the RGB signals from the
RGBDATA
VCLK
Internal RGB
CC
and GND.
p-p
37
48
0.5
36
. To avoid offset in the chromi-
9.0
1
7.0 0.2
VQFP48
0.3
0.2 0.1
25
OUT
12
24
13
) and luminance output
0
0.125
0.10
0
0.1
1
1
2
2
(5) The NT / PAL pin is used to select the video output
system. When the input level is high, NTSC is selected,
and when the input level is low, PAL is selected. When
PAL is selected, the chrominance phase is reversed
once every hour.
(6) A trap filter is connected to the YTRAP pin. This
eliminates the chrominance band component that
includes the luminance signal, and reduces cross-
color. This filter is effective only for composite output
(V
(7) Composite signals are output from the V
internal 75
load. (However, DC cutoff is required.)
(8) Luminance signals and chrominance signals are
output from the Y
internal 75
load. (However, DC cutoff is required.)
(9) Analog RGB signals are output from R
and B
the 75 load. (However, DC cutoff is required.)
OUT
3
), and does not affect luminance output (Y
OUT
. An internal 75
3
driver enables direct drive of the 75
driver enables direct drive of the 75
4
OUT
4
and C
5
driver enables direct drive of
OUT
5
pins, respectively. An
BH7240AKV
OUT
OUT
OUT
pin. An
, G
).
OUT
9
,