ICS181-51
Low EMI Clock Generator
Description
The ICS181-51 generates a low EMI output clock from
a clock or crystal input. The device uses ICS’
proprietary mix of analog and digital Phase-Locked
Loop (PLL) technology to spread the frequency
spectrum of the output, thereby reducing the frequency
amplitude peaks by several dB.
The ICS181-51 offers center spread selection of
+/-0.625% and +/-1.875%. Refer to the MK1714-01/02
for the widest selection of input frequencies and
multipliers.
ICS offers a complete line of EMI reducing clock
generators. Consult us when you need to remove
crystals and oscillators from your board.
Features
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•
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Pin and function compatible to Cypress W181-51
Packaged in 8-pin SOIC
Provides a spread spectrum output clock
Accepts a clock input and provides same frequency
dithered output
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Input frequency of 28 to 75 MHz for Clock input
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Peak reduction by 7dB - 14dB typical on 3rd - 19th
odd harmonics
•
Spread percentage selection for +/-0.625% and
+/-1.875%
•
Operating voltage of 3.3 V and 5 V
•
Advanced, low-power CMOS process
Block Diagram
VDD
FS2:1
SS%
PLLClock
Synthesis
andSpread
Spectrum
Circuitry
CLK
X1/CLKIN
X2
ClockBuffer/
Crystal
Oscillator
GND
MDS 181-51 A
1
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Revision 110404
tel (408 ) 29 7-120 1
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I n t e gra t e d C i r cu i t S y s t e m s
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5 25 Race Street, San Jo se, CA 9 512 6
w w w. i c st . c o m
ICS [ INTEGRATED CIRCUIT SYSTEMS ]
