DATASHEET
TRIPLE PLL FIELD PROG. SPREAD SPECTRUM CLOCK SYNTHESIZER
ICS281
Description
The ICS281 field programmable spread spectrum clock
synthesizer generates up to three high-quality,
high-frequency clock outputs including multiple reference
clocks from a low-frequency crystal input. It is designed to
replace crystals, crystal oscillators and stand alone spread
spectrum devices in most electronic systems.
Using IDT’s VersaClock
TM
software to configure PLLs and
outputs, the ICS281 contains a One-Time Programmable
(OTP) ROM for field programmability. Programming
features include input/output frequencies, spread spectrum
amount and eight selectable configuration registers.
Using Phase-Locked Loop (PLL) techniques, the device
runs from a standard fundamental mode, inexpensive
crystal, or clock. It can replace multiple crystals and
oscillators, saving board space and cost.
The ICS281 is also available in factory programmed custom
versions for high-volume applications.
Features
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Packaged as 16-pin TSSOP – Pb-free, RoHS compliant
Eight addressable registers
Replaces multiple crystals and oscillators
Output frequencies up to 200 MHz at 3.3 V
Configurable Spread Spectrum Modulation
Input crystal frequency of 5 to 27 MHz
Input clock frequency of 3 to 166 MHz
Up to three reference outputs
Operating voltages of 3.3 V
VDDO output control from 1.8 V to 3.3 V
Controllable output drive levels
Advanced, low-power CMOS process
Block Diagram
VDD
PLL1 with
Spread
Spectrum
Divide
Logic
and
Output
Enable
Control
CLK1
3
VDDO
S2:S0
3
OTP
ROM
with PLL
Values
PLL2
CLK2
Crystal or
clock input
X1/ICLK
Crystal
Oscillator
X2
External capacitors
are required with a crystal input.
PLL3
CLK3
GND
3
PDTS
IDT™ / ICS™
TRIPLE PLL FIELD PROG. SPREAD SPECTRUM CLOCK SYNTHESIZER 1
ICS281
REV F 051310
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
