EL4581C
Sync Separator, 50% Slice, S-H, Filter
Features
# NTSC, PAL and SECAM sync
separation
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.
a
# Single supply, 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
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.
# Available in 8-pin DIP and SO-8
pkg.
Applications
# Video special effects
# Video test equipment
# Video distribution
# Displays
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.
# Imaging
# Video data capture
# Video triggers
This device may be used to replace the industry standard
LM1881, offering improved performance and reduced power
consumption.
Ordering Information
Part No. Temp. Range Package Outline
The EL4581C video sync separator is manufactured using
Elantec’s high performance analog CMOS process.
Ý
b
a
EL4581CN 40 C to 85 C 8-Pin DIP MDP0031
§
§
b
a
40 C to 85 C 8-Lead SO MDP0027
EL4581CS
§
§
Connection Diagram
Demo Board
EL4581C SO, P-DIP Packages
A dedicated demo board is not
available. However, this device can
be placed on the EL4584/5 Demo
Board.
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 ]
