ML6423CS-2 MICRO-LINEAR [Micro Linear Corporation], ML6423CS-2 Datasheet - Page 6

• Manufacturer Part Number: ML6423CS-2
• Description: Dual S-Video Lowpass Filter with Phase and Sinx/x Equalization
• Manufacturer: MICRO-LINEAR [Micro Linear Corporation]

ML6423
FUNCTIONAL DESCRIPTION
The ML6423 single-chip dual video filter is intended for
low cost professional and consumer video applications.
Each of the two channels incorporates an input buffer
amplifier, a 6th-order lowpass filter, a 1st-order allpass
equalizer, sinx/x equalizer and an output 2X gain
amplifier capable of driving 75
output (B) is the sum of the A and C inputs and have the
identical output amplifier as the A and C channels.
The ML6423 can be driven by a DAC with RANGE down
to 0V. When RANGE is low the input range is 0.5V to
1.5V. When the input signal range is 0V to 0.1V, RANGE
should be tied high. In this case, an offset is added to the
input so that the output swing is kept between 0.5V to
2.5V. The output amplifier is capable of driving up to
24mA of peak current; therefore the output voltage should
not exceed 1.8V when driving 75
6
+5V
0.1 F
INPUT SIGNAL
= 1V
V
V
V
OUT
OUT
IN
1nF
C
P-P
C
B
+
100 F
85
75
75
DECOUPLING
0.1 F
INPUT
INPUT
TERMINATION
RESISTOR
FB2
100 F
+
FB1
to ground. A third
BIAS
DC
Figure 4. ML6423 AC Coupled DC Bias Test Circuit
to ground.
SUPPLY NOISE
CLAMPING
100
2.56k
1k
0.1 F
1 F
1nF
0.1 F
1nF
1
2
3
4
5
6
7
8
V
GND
GNDC
V
NC
V
V
V
IN
CC
OUT
CC
OUT
C
C
C
B
APPLICATION GUIDELINES
OUTPUT & INPUT CONSIDERATIONS
The dual filters have 2X gain. The circuit has 2X gain
(6dB) when connected to a 150W load, and 0dB gain
when driving a 75
The output may be either AC or DC coupled. For AC
coupling, the –3dB point should be 5Hz or less. There
must also be a DC path of 500 to ground for output
biasing. The ML6423-5 provides higher sink current to
better drive AC coupled loads.
The input resistance is 4k . The input may be either DC
or AC coupled. (Note that each input sources 80 to 125µA
of bias current). The ML6423 is designed to be directly
driven by a DAC. For current output video DACs, a 75
or 150
DAC output (filter input).
RANGE
V
GNDA
GNDB
OUT
V
V
V
CC
CC
resistor to ground may need to be added to the
IN
NC
A
A
A
B
16
15
14
13
12
11
10
9
0.1 F
0.1 F
1nF
1nF
2.56k
load via a 75
1k
100
1 F
75
series output resistor.
0.1 F
100 F
+
85
V
OUT
V
A
IN
A