EL4581C
EL4581C
Sync Separator 50% Slice S-H Filter
Features
NTSC PAL and SECAM sync
separation
Single supply
a
5V
Precision 50% slicing internal
caps
Built-in color burst filter
Decodes non-standard verticals
Pin compatible with LM1881
Low power
Typically 1 5 mA supply current
Resistor programmable scan rate
Few external components
Available in 8-pin DIP and SO-8
pkg
General Description
The EL4581C extracts timing information from standard nega-
tive going video sync found in NTSC PAL and SECAM broad-
cast systems It can also be used in non standard formats and
with computer graphics systems at higher scan rates by adjust-
ing a single external resistor When the input does not have
correct serration pulses in the vertical interval a default verti-
cal output is produced
Outputs are composite sync vertical sync burst back porch
output and odd even output The later operates only in inter-
laced scan formats
The EL4581C provides a reliable method of determining correct
sync slide level by setting it to the mid-point between sync tip
and blanking level at the back porch This 50% level is deter-
mined by two internal self timing sample and hold circuits that
track sync tip and back porch levels This also provides a degree
of hum and noise rejection to the input signal and compensates
for varying input levels of 0 5 p-p to 2 0 Vp-p
A built in linear phase third order low pass filter attenuates
the chroma signal in color systems to prevent incorrectly set
color burst from disturbing the 50% sync slide
This device may be used to replace the industry standard
LM1881 offering improved performance and reduced power
consumption
The EL4581C video sync separator is manufactured using
Elantec’s high performance analog CMOS process
Applications
Video special effects
Video test equipment
Video distribution
Displays
Imaging
Video data capture
Video triggers
Ordering Information
Part No
Temp Range
Package Outline
EL4581CN
b
40 C to
a
85 C 8-Pin DIP MDP0031
EL4581CS
b
40 C to
a
85 C 8-Lead SO MDP0027
Connection Diagram
EL4581C SO P-DIP Packages
Demo Board
A dedicated demo board is not
available However this device can
be placed on the EL4584 5 Demo
Board
January 1996 Rev B
4581 – 1
Top View
Manufactured under U S Patent No 5 528 303
Note
All information contained in this data sheet has been carefully checked and is believed to be accurate as of the date of publication however this data sheet cannot be a ‘‘controlled document’’ Current revisions if any to these
specifications are maintained at the factory and are available upon your request We recommend checking the revision level before finalization of your design documentation
1993 Elantec Inc
ELANTEC [ ELANTEC SEMICONDUCTOR ]
