September 1999
PRELIMINARY
ML6426
High Bandwidth Triple Video Filters with Buffered
Outputs for RGB orYUV
GENERAL DESCRIPTION
FEATURES
The ML6426 are a family of triple video filters with
buffered outputs. There are several versions of the
ML6426, each with different passband cut-off frequencies
of 6.7MHz, 12MHz, 24MHz, 30MHz, 36MHz, and
■ 5V ±10% operation
■ RGB/YUV filters for ATSC Digital Television VESA
Standard
th
48MHz. Each channel contains a 4 -order Butterworth
lowpass reconstruction video filter. The filter is optimized
for minimum overshoot and flat group delay and
guaranteed differential gain and phase at the outputs of
the integrated cable drivers.
■ 2:1 Mux Inputs for multiple RGB/YUV inputs
■ Triple Reconstruction Filter options for 6.7, 12, 24, 30,
36, and 48MHz to handle various line rates
All input signals from DACs are AC coupled into the
ML6426. All channels have DC restore circuitry to clamp
the DC input levels during video H-sync, using an output
feedback clamp. An external H-sync signal is required for
this purpose.
■ Multiple ML6426 outputs can be paralleled to drive
RGB/YUV outputs at different frequencies for various
line rates by means of Disable/Enable pin.
■ 6dB drivers and sync tip clamps for DC restore
■ DC restore with minimal tilt
All outputs must be AC coupled into their loads. Each
output can drive 2V into a 150W load. All channels
P-P
have a gain of 2 (6dB) at 1V input levels.
■ 0.4% differential gain on all channels
0.4º differential phase on all channels
P-P
0.8% total harmonic distortion on all channels
■ 2kV ESD protection
BLOCK DIAGRAM
12
4
V
V
CC
CCO
R
R
A/Y
A
IN
IN
2
5
R
/Y
OUT OUT
4th-ORDER
FILTER A
MUX
MUX
MUX
B/Y
B
×2
×2
13
11
IN
IN
+
TRANSCONDUCTANCE
ERROR AMP
G
G
A/U
A
IN
IN
–
0.5V
G
/U
6
7
OUT OUT
4th-ORDER
FILTER B
/U
IN IN
B
+
–
TRANSCONDUCTANCE
ERROR AMP
0.5V
0.5V
B
B
A/V
A
IN
IN
IN
B
/V
OUT OUT
8
9
4th-ORDER
FILTER C
×2
10
B/V
B
IN
+
–
TRANSCONDUCTANCE
ERROR AMP
A/B MUX
1
SYNCIN
16
DISABLE
15
GNDO
14
GND
3
ML6426-1
6.7MHz
6.7MHz
6.7MHz
ML6426-2
12MHz
12MHz
12MHz
ML6426-3
24MHz
24MHz
24MHz
ML6426-4
30MHz
30MHz
30MHz
ML6426-5
36MHz
36MHz
36MHz
ML6426-6
Filter A
Filter B
Filter C
48MHz
48MHz
48MHz
1