ML6428 Datasheet, PDF (1/11 Pages) Fairchild Semiconductor – S-Video Filter and 75 Ω Line Drivers with Summed Composite Output

ML6428 S-Video Filter and 75W Line Drivers with
Summed Composite Output
GENERAL DESCRIPTION
The ML6428 is a dual Y/C 4th-order Butterworth lowpass
video filter optimized for minimum overshoot and flat
group delay. The device also contains a summing circuit
to generate filtered composite video.
The Y and C input signals from DACs are AC coupled into
the ML6428. Both channels have DC restore circuitry to
clamp the DC input levels during video sync. The Y
channel uses a sync tip clamp. The CV and the C
channels share a feedback clamp.
All outputs must be AC coupled into their loads for the -1
and -3 versions. The -2 and -4 versions are DC coupled.
All inputs (-1, -2, -3 and -4 versions) are AC coupled. The
Y or C outputs can drive 2VP-P into a 150W load, while
the CV output can drive 2VP-P into 75W. Thus the CV
output is capable of driving two independent 150W loads
to 2VP-P.
On the CV output, one of the 75W loads can be shorted to
ground with no loss of drive to the remaining load. The Y,
C and CV channels have a gain of 2 (6dB) with 1VP-P
input levels.
BLOCK DIAGRAM
FEATURES
s 6.7MHz Y and C filters, with CV out for NTSC or PAL
s 75W cable line driver for Y, C, CV, and TV modulator
s 43dB stopband attenuation at 27MHz
s 1dB flatness up to 4.8MHz
s No external frequency select components or clocks
s 12ns group delay flatness up to 10MHz
s 5% overshoot on any input edge
s AC coupled input and output (ML6428CS-1 and -3)
s AC coupled input and DC coupled output
(ML6428CS-2 and -4)
s 0.4% differential gain on all channels, 0.4º differential
phase on all channels
s 0.7% total harmonic distortion on all channels
s 5V ±10% operation
s DC restore with low tilt
VCC
VCCO
2
7
YIN ₁
4th-ORDER
FILTER
+
SYNC TIP CLAMP
Σ
TRANSCONDUCTANCE
+
ERROR AMP
BUFFER
8 _YOUT
BUFFER
6 _CVOUT
CIN 4
4th-ORDER
FILTER
3
GND
BUFFER
5 _COUT
DATASHEET
June, 2000
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