PRELIMINARY DATASHEET
TRIPLE PLL FIELD PROG. SPREAD SPECTRUM CLOCK SYNTHESIZER
ICS291
Description
The ICS291 field programmable spread spectrum clock
synthesizer generates up to six 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 ICS’ VersaClock
TM
software to configure PLLs and
outputs, the ICS291 contains a One-Time Programmable
(OTP) ROM for field programmability. Programming
features include input/output frequencies, spread spectrum
amount, eight selectable configuration registers and up to
two sets of three low-skew outputs.
Each of the two output groups are powered by a separate
VDDO voltage. VDDO may vary from 1.8 V to VDD.
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 ICS291 is also available in factory programmed custom
versions for high-volume applications.
Features
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Packaged as 20-pin TSSOP
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
Clock input frequency of 3 to 166 MHz
Up to six reference outputs
Separate 1.8 to 3.3 V VDDO output level controls for
each bank of 3 outputs
Up to two sets of three low-skew outputs
Operating voltages of 3.3 V
Controllable output drive levels
Advanced, low-power CMOS process
Available in Pb (lead) free packaging
Block Diagram
VDD
PLL1 with
Spread
Spectrum
Divide
Logic
and
Output
Enable
Control
3
VDDO1
S2:S0
3
OTP
ROM
with PLL
Values
CLK1
CLK2
CLK3
PLL2
CLK4
CLK5
CLK6
PLL3
X1/ICLK
Crystal or
Clock Input
Crystal
Oscillator
X2
External capacitors
are required with a crystal input.
3
GND
PDTS
VDDO2
IDT™ / ICS™
TRIPLE PLL FIELD PROG. SPREAD SPECTRUM CLOCK SYNTHESIZER 1
ICS291
REV D 061306
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
