ICS291 Datasheet, PDF (1/8 Pages) Integrated Circuit Systems – Triple PLL Field Prog. Spread Spectrum Clock Synthesizer

PRELIMINARY INFORMATION
ICS291
Triple PLL Field Prog. Spread Spectrum Clock Synthesizer
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.
Block Diagram
Features
• 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
VDD ³
VDDO1
3
S2:S0
OTP
ROM
with PLL
Values
X1/ICLK
Crystal or
Clock Input
X2
Crystal
Oscillator
External capacitors
are required with a crystal input.
PLL1 with
Spread
Spectrum
PLL2
PLL3
Divide
Logic
and
Output
Enable
Control
CLK1
CLK2
CLK3
CLK4
CLK5
CLK6
3
GND
PDTS
VDDO2
MDS 291 C
1
Revision 062205
Integrated Circuit Systems, Inc. ● 525 Race Street, San Jose, CA 95126 ● tel [phone] ● www.icst.com