ML6428
S-Video Filter and 75W Line Drivers with
Summed Composite Output
FEATURES
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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.
6.7MHz Y and C filters, with CV out for NTSC or PAL
75W cable line driver for Y, C, CV, and TV modulator
43dB stopband attenuation at 27MHz
1dB flatness up to 4.8MHz
No external frequency select components or clocks
12ns group delay flatness up to 10MHz
5% overshoot on any input edge
AC coupled input and output (ML6428CS-1 and -3)
AC coupled input and DC coupled output
(ML6428CS-2 and -4)
0.4% differential gain on all channels, 0.4º differential
phase on all channels
0.7% total harmonic distortion on all channels
5V ±10% operation
DC restore with low tilt
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BLOCK DIAGRAM
VCC
2
VCCO
7
YIN
1
4th-ORDER
FILTER
8
BUFFER
+
YOUT
SYNC TIP CLAMP
Σ
TRANSCONDUCTANCE
ERROR AMP
+
6
BUFFER
CVOUT
CIN
4
4th-ORDER
FILTER
5
BUFFER
COUT
3
GND
DATASHEET
June, 2000
1
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
