Datasheet ML6428CS-4, ML6428CS-3, ML6428CS-1, ML6428CS-2 Datasheet (Micro Linear Corporation)
Page 1
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.
FEATURES
■ 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
BLOCK DIAGRAM
YIN
CIN
1
4
SYNC TIP CLAMP
TRANSCONDUCTANCE
ERROR AMP
4th-ORDER
FILTER
4th-ORDER
FILTER
■ DC restore with low tilt
VCCOVCC
72
BUFFER
+
Σ
+
3
GND
BUFFER
BUFFER
8
6
5
YOUT
CVOUT
COUT
DATASHEET June, 2000
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ML6428
TABLE OF CONTENTS
General Description ................................................................................................................................................... 1
Features...................................................................................................................................................................... 1
Block Diagram ........................................................................................................................................................... 1
Pin Configuration ....................................................................................................................................................... 3
Pin Descriptions ......................................................................................................................................................... 3
Absolute Maximum Ratings........................................................................................................................................ 4
Operating Conditions ................................................................................................................................................. 4
Electrical Characteristics............................................................................................................................................ 4
Functional Description ............................................................................................................................................... 6
Performance Data....................................................................................................................................................... 7
Typical Applications ................................................................................................................................................... 8
Physical Dimensions .................................................................................................................................................. 11
Ordering Information .................................................................................................................................................. 11
WARRANTY
© Micro Linear 2000. is a registered trademark of Micro Linear Corporation. All other trademarks are the property of their
respective owners.
Products described herein may be covered by one or more of the following U.S. patents: 4,897,611; 4,964,026; 5,027,116;
5,281,862; 5,283,483; 5,418,502; 5,508,570; 5,510,727; 5,523,940; 5,546,017; 5,559,470; 5,565,761; 5,592,128; 5,594,376;
5,652,479; 5,661,427; 5,663,874; 5,672,959; 5,689,167; 5,714,897; 5,717,798; 5,742,151; 5,747,977; 5,754,012; 5,757,174;
5,767,653; 5,777,514; 5,793,168; 5,798,635; 5,804,950; 5,808,455; 5,811,999; 5,818,207; 5,818,669; 5,825,165; 5,825,223;
5,838,723; 5.844,378; 5,844,941. Japan: 2,598,946; 2,619,299; 2,704,176; 2,821,714. Other patents are pending.
Micro Linear makes no representations or warranties with respect to the accuracy, utility, or completeness of the contents
of this publication and reserves the right to make changes to specifications and product descriptions at any time without
notice. No license, express or implied, by estoppel or otherwise, to any patents or other intellectual property rights is granted
by this document. The circuits contained in this document are offered as possible applications only. Particular uses or
applications may invalidate some of the specifications and/or product descriptions contained herein. The customer is urged
to perform its own engineering review before deciding on a particular application. Micro Linear assumes no liability
whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of Micro Linear products including
liability or warranties relating to merchantability, fitness for a particular purpose, or infringement of any intellectual property
right. Micro Linear products are not designed for use in medical, life saving, or life sustaining applications.
2
DATASHEET June, 2000
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PIN CONFIGURATION
ML6428
8-Pin SOIC (S08)
YIN
VCC
GND
CIN
1
2
3
4
TOP VIEW
ML6428
8
YOUT
7
VCCO
6
CVOUT
5
COUT
PIN DESCRIPTION
PIN NAME FUNCTION
1 YIN Luminance input
2 VCC 5V supply for filters and references
3 GND Ground
4 CIN Chrominance input
PIN NAME FUNCTION
5 COUT Chrominance output
6 CVOUT Composite video output
7 VCCO 5V supply for output stages
8 YOUT Luminance output
DATASHEET June, 2000
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ML6428
ELECTRICAL CHARACTERISTICS
ABSOLUTE MAXIMUM RATINGS
Absolute maximum ratings are those values beyond which
the device could be permanently damaged. Absolute
OPERATING CONDITIONS
Temperature Range ....................................... 0°C to 70°C
VCC Range ..................................................4.5V to 5.5V
maximum ratings are stress ratings only and functional
device operation is not implied.
DC Supply Voltage ........................................ -0.3V to 7V
Analog & Digital I/O ............ GND – 0.3V to VCC + 0.3V
Output Current (Continuous)
CV Channel ........................................................ 60mA
C and Y Channels ................................................ 30mA
Junction Temperature .............................................. 150°C
Storage Temperature Range ..................... –65°C to 150°C
Lead Temperature (Soldering, 10 sec) ..................... 260°C
Thermal Resistance (qJA)..................................... 67°C/W
ELECTRICAL TABLE
Unless otherwise specified, VCC = 5V ±10%, All inputs AC coupled with 100nF, TA = Operating Temperature Range (Note 1)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
ICC Supply Current No Load (VCC = 5.0V) 52 80 mA
AV Low Frequency Gain (All Channels) VIN = 100mVP-P at 300KHz 5.34 6.0 6.65 dB
C DC Output Level (During Sync) Sync Present on Y 1.7 1.9 2.3 V
Y Sync Output Level ML6428-1 Sync Present on Y 0.7 0.9 1.3 V
ML6428-3
ML6428-2 Sync Present on Y 0.35 0.54 0.95 V
ML6428-4
Y+C Sync Output Level ML6428-1 Sync Present on Y 0.7 0.92 1.3 V
ML6428-3
ML6428-2 Sync Present on Y 0.35 0.48 0.95 V
ML6428-4
tCLAMP Clamp Response Time (Y Channel) Settled to Within 10mV 2 ms
f1dB -1dB Bandwidth (Flatness) (All Channels) 4.0 4.8 MHz
fC -3dB Bandwidth (Flatness) (All Channels) 6.7 MHz
0.8fC 0.8 x fC Attenuation (Y, C) 1.5 dB
fSB Stopband Rejection (All Channels) fIN = 27MHz to 100MHz worst case –38 –42 dB
Vi Input Signal Dynamic Range (All Channels) AC Coupled ML6428-1, -2 1.0 1.4 VP-P
ML6428-3, -4 1.2 1.4 VP-P
NOISE Output Noise (All Channels) 25Hz to 50MHz 2.3 mVRMS
OS Peak Overshoot (All Channels) 2VP-P Output Pulse (loaded) 4.3 %
ISC Output Short Circuit Current (All Channels) VOUT C, Y, or CV (Note 2) 100 mA
CL Output Shunt Capacitance (All Channels) All Outputs 35 pF
dG Differential Gain (All Channels) All Outputs 0.4 %
d F Differential Phase (All Channels) All Outputs 0.4 º
THD Output Distortion (All Channels) VOUT = 1.8VP-P, 0.7 %
Y/C Out at 3.58MHz/4.43MHz
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ML6428
ELECTRICAL TABLE (CONTINUED)
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
XTALK Crosstalk From C Input of 0.5VP-P –55 dB
at 3.58MHz/4.43MHz, to Y Output
From Y Input of 0.4VP-P at 3.58MHz, –58 dB
to C Output
PSRR PSRR (All Channels) 0.5VP-P (100kHz) at VCC –49 dB
tpd Group Delay (All Channels) 100kHz 60 ns
Dtpd Group Delay Deviation from Flatness to 3.58MHz (NTSC) 4 ns
(All Channels) to 4.43MHz (PAL) without peaking 7 ns
(see Figures 7 to 11)
to 10MHz 12 ns
tSKEW Skew Between Y & C Outputs 1ns
Note 1: Limits are guaranteed by 100% testing, sampling, or correlation with worst case test conditions.
Note 2: Sustained short circuit protection limited to 10 seconds.
DATASHEET June, 2000
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ML6428
FUNCTIONAL DESCRIPTION
The ML6428 is a dual monolithic continuous time video
filter designed for reconstructing the luminance and
chrominance signals from an S-Video D/A source.
Composite video output is generated by summing the Y
and C outputs. The ML6428 is intended for use in AC
coupled input and output applications. The ML6428CS-2,
-4 is intended for AC coupled input and DC coupled
output applications (see Figures 5 and 6).
The filters have a 4th-order Butterworth characteristic with
an optimization toward low overshoot and flat group
delay. All outputs are capable of driving 2VP-P into AC
coupled 150W video loads, with up to 35pF of load
capacitance at the output pin. The CV output can drive
two video loads plus a high-impedance modulator. Thus
the CV output is intended to simultaneously drive a VCR,
a TV, and a high-impedance modulator. Y and C are
capable of driving a 75W load at 1VP-P. The ML6428 is
capable of driving two composite loads and a TV
modulator simultaneously.
All channels are clamped during sync to establish the
appropriate output voltage swing range. Thus the input
coupling capacitors do not behave according to the
conventional RC time constant. Clamping for all
channels settles within 2ms of a change in video input
sources.
In most applications, the ML6428's input coupling
capacitors are 0.1µF. The Y input sinks 1.6µA during
active video, which nominally tilts a horizontal line by
2mV (max) at the Y output (Figure 4). During sync, the
clamp typically sources 20µA to restore the DC level. The
net result is that the average input current is zero.
LUMINANCE (Y) I/O
The luma input is driven by either a low impedance
source of 1VP-P or the output of a 75W terminated line.
The input is required to be AC coupled via a 0.1uF
coupling capacitor which allows for a nominal settling
time of 2ms. The luma output is capable of driving an AC
coupled 150W load at 2VP-P or 1VP-P into a 75W load.
Up to 35pF of load capacitance (at the output pin) can be
driven without stability or slew issues. A 220µF AC
coupling capacitor is recommended at the output
(ML6428-1, -3 only).
CHROMINANCE (C) I/O
The chroma input is driven by a low impedance source of
0.7VP-P or the output of a 75W terminated line. The input
is required to be AC coupled via a 0.1uF coupling
capacitor which allows for a nominal clamping time of
1ms. The chroma output is capable of driving an AC
coupled 150W load at 2VP-P or 1VP-P into a 75W load.
Up to 35pF of load capacitance can be driven without
stability or slew issues. A 220µF AC coupling capacitor is
recommended at the output (ML6428-1, -3 only).
COMPOSITE VIDEO (CV) OUTPUT
The composite video output is capable of driving 2 CV
loads to 2VP-P and a high input impedance CV modulator.
It is intended to drive three devices: TV, VCR, and a
modulator. The TV or VCR input can be shorted to ground
and the other outputs will still meet specifications. Up to
35pF of load capacitance (at the output pin) can be
driven without stability or slew issues.
Any change in the input coupling capacitor's value will
inversely alter the amount of tilt per line. Such a change
will also linearly affect the clamp response times.
The C channel has no pulldown current sources and is
essentially tilt-free. Its input is clamped by a feedback
amp which responds to the CV output. Since CV = Y+C,
the CV output will droop by the same amount as Y during
active video, and will rise by the same amount as Y
during sync.
The ML6428 is robust and stable under all stated load and
input conditions. Capacitavely bypassing both VCC pins
directly to ground ensures this performance. (See Figures
5 and 6)
USING THE ML6428 FOR PAL APPLICATIONS
The ML6428 can be optimized for PAL video by adding
frequency peaking to the composite and S-video outputs.
Figures 7 and 8 illustrate the use of a additional external
capacitor, 330pF, added in parallel to the output source
termination resistor. This raises the frequency response
from 1.6 dB down at 4.8Mhz to 0.35dB down at 4.8MHz
allowing for accurate reproduction of the upper sideband
of the PAL subcarrier. Figure 9 shows the frequency
response of PAL video with various values of peaking
capacitors (0pF, 220pF, 270pF, 330pF) between 0 and
10MHz.
For NTSC applications without the peaking capacitor the
rejection at 27MHz is 42dB (typical) while for PAL
applications with the peaking capacitor the rejection at
27MHz is 38dB (typical). This is shown in Figure 10. The
differential group delay is shown in Figure 11 with and
without a peaking capacitor (0pF, 220pF, 270pF, and
330pF) varies slightly with capacitance, going from 8ns to
13ns.
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DATASHEET June, 2000
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PERFORMANCE DATA
ML6428
1
0
–1
–2
AMPLITUDE (dB)
–3
–4
0 0.1 1 10
FREQUENCY (MHz)
Figure 1. Passband Flatness
All outputs. (Normalized) Passband is ripple-free.
20
0
–20
–40
AMPLITUDE (dB)
–60
–80
0.01 0.1 1 10010
FREQUENCY (MHz)
Figure 2. Passband/Stopband Rejection Ratios
All outputs. (Normalized)
90
70
50
DELAY (ns)
30
10
159
FREQUENCY (MHz)
1137481026
Figure 3. Group Delay, all Outputs
Low frequency group delay is 62ns. At 3.58MHz group
delay increases by only 4ns. At 4.43MHz group delay
increases by only 7ns. The maximum deviation from flat
group delay of 12ns occurs at 6MHz.
SCALE: 200mV/DIV
REGION OF TILT
SCALE: 200ms/DIV
Figure 4. DC Restore Performance of Luma Output
Luma ramp test pattern is shown to have minimal tilt
during vertical sync.
In most applications, the ML6428's input coupling
capacitors are 0.1µF. The Y input sinks 1.6µA during
active video, which tilts a horizontal line by 2mV at the
Y output
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ML6428
TYPICAL APPLICATIONS
ML6428-1, -3
0.1µF
YIN
CIN
5V
0.1µF
1
4
4th-ORDER
FILTER
+
Σ
+
4th-ORDER
FILTER
1µF0.1µF
8
6
5
372
220µF
220µF
220µF
C*
220µF
* C AND R DEPEND ON THE INPUT IMPEDANCE OF LOAD
75Ω
75Ω
75Ω
R*
75Ω
VIDEO CABLES
YOUT
75Ω
CVOUT
75Ω
CVOUT
75Ω
ON-CHANNEL
MODULATOR,
VCR, AND TV
COUT
75Ω
YIN
CIN
5V
0.1µF
0.1µF
Figure 5. AC Coupled S-Video and Composite Video Line Driver for NTSC
ML6428-2, -4
1
4th-ORDER
FILTER
+
Σ
+
4
4th-ORDER
FILTER
1µF0.1µF
8
6
5
372
* C AND R DEPEND ON THE INPUT IMPEDANCE OF LOAD
75Ω
75Ω
75Ω
C*
R*
75Ω
VIDEO CABLES
YOUT
75Ω
CVOUT
75Ω
CVOUT
75Ω
ON-CHANNEL
MODULATOR,
VCR, AND TV
COUT
75Ω
Figure 6. DC Coupled S-Video and Composite Video Line Driver for NTSC
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DATASHEET June, 2000
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TYPICAL APPLICATIONS
ML6428-1, -3
0.1µF
YIN
1
4th-ORDER
FILTER
+
Σ
+
4th-ORDER
FILTER
372
1µF0.1µF
CIN
5V
0.1µF
4
ML6428
8
6
5
220µF
220µF
220µF
C1*
220µF
* C1, C2, AND R DEPEND ON THE INPUT IMPEDANCE OF LOAD
75Ω
330pF
75Ω
330pF
75Ω
330pF
R*
C2*
75Ω
330pF
VIDEO CABLES
YOUT
75Ω
CVOUT
75Ω
CVOUT
75Ω
ON-CHANNEL
MODULATOR,
VCR, AND TV
COUT
75Ω
YIN
CIN
5V
0.1µF
0.1µF
Figure 7. AC Coupled S-Video and Composite Video Line Driver for PAL
ML6428-2, -4
1
4th-ORDER
FILTER
+
Σ
+
4
4th-ORDER
FILTER
1µF0.1µF
8
6
5
C1*
372
* C1, C2, AND R DEPEND ON THE INPUT IMPEDANCE OF LOAD
75Ω
330pF
75Ω
330pF
75Ω
330pF
R*
C2
75Ω
330pF
VIDEO CABLES
YOUT
75Ω
CVOUT
75Ω
CVOUT
75Ω
ON-CHANNEL
MODULATOR,
VCR, AND TV
COUT
75Ω
Figure 8. DC Coupled S-Video and Composite Video Line Driver for PAL
DATASHEET June, 2000
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ML6428
TYPICAL APPLICATIONS
–0.5
0
0.5
1
AMPLITUDE (dB)
1.5
330pF
2
2.5
04682
270pF
220pF
0pF
1573
FREQUENCY (MHz)
0.35dB
WITH
PEAKING
1.7dB
WITHOUT
PEAKING
Figure 9. NTSC/PAL Video Frequency Response With and Without Peaking Capacitor
0
10
NTSC/PAL
–38dB
20
WITH
PEAKING
30
AMPLITUDE (dB)
40
50
0121830246
31521279
330pF
270pF
220pF
0pF
NTSC/PAL
–42dB
WITHOUT
PEAKING
FREQUENCY (MHz)
Figure 10. Stopband Rejection at 27MHz With and Without Peaking Capacitor
10
8ns
GROUP
DELAY
WITHOUT
PEAKING
0
13ns GROUP
DELAY
DELAY (ns)
–10
–20
0461082
15793
WITH 330pF
PEAKING
330pF
270pF
220pF
0pF
FREQUENCY (MHz)
10
Figure 11. Group Delay at 5.5MHz (PAL) With and Without Peaking Capacitor
DATASHEET June, 2000
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PHYSICAL DIMENSIONS inches (millimeters)
Package: S08
8-Pin SOIC
0.189 - 0.199
(4.80 - 5.06)
8
ML6428
0.017 - 0.027
(0.43 - 0.69)
(4 PLACES)
0.055 - 0.061
(1.40 - 1.55)
1
0.012 - 0.020
(0.30 - 0.51)
SEATING PLANE
ORDERING INFORMATION
PIN 1 ID
0.050 BSC
(1.27 BSC)
0.148 - 0.158
(3.76 - 4.01)
0.059 - 0.069
(1.49 - 1.75)
0.228 - 0.244
(5.79 - 6.20)
0.004 - 0.010
(0.10 - 0.26)
0º - 8º
0.015 - 0.035
(0.38 - 0.89)
0.006 - 0.010
(0.15 - 0.26)
PART NUMBER TEMPERATURE RANGE PACKAGE
ML6428CS-1 0°C to 70°C 8 Pin SOIC (S08)
ML6428CS-2 0°C to 70°C 8 Pin SOIC (S08)
ML6428CS-3 0°C to 70°C 8 Pin SOIC (S08)
ML6428CS-4 0°C to 70°C 8 Pin SOIC (S08)
Micro Linear Corporation
2092 Concourse Drive
San Jose, CA 95131
Tel: (408) 433-5200
Fax: (408) 432-0295
www.microlinear.com
DS6428-02
DATASHEET June, 2000
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