DATASHEET
TRIPLE PLL FIELD PROG. SPREAD SPECTRUM CLOCK SYNTHESIZER ICS291
Description
Features
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.
• Packaged as 20-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
• Clock input frequency of 3 to 166 MHz
• Up to six reference outputs
TM
Using IDT’s VersaClock 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.
• 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
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.
Block Diagram
VDDO1
3
VDD
PLL1 with
Spread
Spectrum
3
S2:S0
OTP
CLK1
CLK2
CLK3
ROM
with PLL
Values
Divide
Logic
and
Output
Enable
Control
PLL2
PLL3
CLK4
CLK5
CLK6
X1/ICLK
Crystal
Oscillator
Crystal or
Clock Input
X2
3
External capacitors
are required with a crystal input.
GND
VDDO2
PDTS
IDT™ / ICS™ TRIPLE PLL FIELD PROG. SPREAD SPECTRUM CLOCK SYNTHESIZER 1
ICS291
REV F 051310
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
