DATASHEET
TRIPLE PLL FIELD PROG. SPREAD SPECTRUM CLOCK SYNTHESIZER ICS281
Description
Features
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.
• 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
TM
Using IDT’s VersaClock 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.
• Advanced, low-power CMOS process
The ICS281 is also available in factory programmed custom
versions for high-volume applications.
Block Diagram
3
VDDO
VDD
PLL1 with
Spread
Spectrum
3
S2:S0
OTP
ROM
CLK1
CLK2
CLK3
with PLL
Values
Divide
Logic
and
Output
Enable
Control
PLL2
PLL3
Crystal or
clock input
X1/ICLK
Crystal
Oscillator
X2
3
GND
External capacitors
are required with a crystal input.
PDTS
IDT™ / ICS™ TRIPLE PLL FIELD PROG. SPREAD SPECTRUM CLOCK SYNTHESIZER 1
ICS281
REV F 051310
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
