ICS1523
Video Clock Synthesizer with I
2
C Programmable Delay
General Description
The ICS1523 is a low-cost, high-performance
frequency generator. It is well suited to general
purpose phase controlled clock synthesis as well as
line-locked and genlocked high-resolution video
applications. Using ICS’s advanced low-voltage
CMOS mixed-mode technology, the ICS1523 is an
effective phase controlled clock synthesizer and also
supports video projectors and displays at resolutions
from VGA to beyond UXGA.
The ICS1523 offers clock outputs in both differential
(to 250 MHz) and single-ended (to 150 MHz) formats.
Dynamic Phase Adjust (DPA) allows I
2
C™ control of
the output clock’s phase relative to the input sync
signal. A second, half speed set of outputs that can be
separately enabled allows such applications as
clocking analog-to-digital converters. The FUNC pin
provides either the regenerated input from the
phase-locked loop (PLL) divider chain output, or the
input HSYNC after being sharpened by the Schmitt
trigger. Both signals are then delayed by the DPA.
The advanced PLL uses either its internal
programmable feedback divider or an external divider.
Either the internal or external loop filters is software
selectable. The COAST input pin disables the PLL’s
charge pump, causing the device to idle at the current
speed for short periods of time, such as vertical
blanking intervals.
The device is programmed by a standard I
2
C-bus
serial interface and is available in a 24-pin, wide
small-outline integrated circuit (SOIC) package.
Features
• Low Jitter
• Wide input frequency range
• 15.734 kHz to 100 MHz
• PECL differential outputs
• Up to 250 MHz
• SSTL_3 Single-ended clock outputs
• Up to 150 MHz
• Dynamic Phase Adjust (DPA) for all outputs
• I
2
C controlled phase adjustment
• Full clock cycle down to 1/64 of a clock
• Double-buffered control registers
• External or internal loop filter selection
• COAST input can disable charge pump
• 3.3 VDD
• 5 volt Tolerant Inputs
• Industry Standard I
2
C-bus programming interface
• PLL Lock detection via I
2
C or LOCK/REF output pin
• 24-pin 300-mil SOIC package
• Available in Pb-free packaging
Applications
• Frequency synthesis
• LCD monitors, video projectors and plasma displays
• Genlocking multiple video subsystems
Pin Configuration
ICS1523 Functional Diagram
External Loop Filter (optional)
OSC
HSYNC
I
2
C I/F
CLK
CLK/2
FUNC
24-pin SOIC
MDS 1523 Y
Integrated Circuit Systems
1
525 Race Street, San Jose, CA 95126
tel (408) 297-1201
Revision 110905
www.icst.com
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