ICS342
Field Programmable Dual Output SS VersaClock Synthesizer
Description
The ICS342 is a low cost, dual-output, field
programmable clock synthesizer. The ICS342 can
generate two output frequencies from 250 kHz to 200
MHz, using up to two independently configurable PLLs.
The outputs may employ Spread Spectrum techniques
to reduce system electro-magnetic interference (EMI).
Using ICS’ VersaClockTM software to configure the
PLL and output, the ICS342 contains a One-Time
Programmable (OTP) ROM to allow field
programmability. Programming features include 2
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 device also has a power down feature that
tri-states the clock outputs and turns off the PLLs when
the PDTS pin is taken low.
The ICS342 is also available in factory programmed
custom versions for high-volume applications.
Features
• 8-pin SOIC package
• Highly accurate frequency generation
• M/N Multiplier PLL: M = 1...2048, N = 1...1024
• Output clock frequencies up to 200 MHz
• Two ROM locations for frequency and spread
selection
• Spread spectrum capability for lower system EMI
• Center or Down Spread up to 4% total
• Selectable 32 kHz or 120 kHz modulation
• Input crystal frequency from 5 to 27 MHz
• Input clock frequency from 2 to 50 MHz
• Operating voltage of 3.3 V
• Advanced, low power CMOS process
• For one output clock, use the ICS341. For three
output clocks, see the ICS343. For more than three
outputs, see the ICS345 or ICS348.
• Available in Pb (lead) free packaging
Block Diagram
SEL
Crystal or
clock input
X1/ICLK
X2
OTP ROM
with PLL
Divider
Values
Crystal
Oscillator
External capacitors are
required with a crystal input.
VDD
PLL Clock Synthesis,
Spred Spectrum and
Control Circuitry
CLK1
CLK2
GND
PDTS (both outputs and PLL)
MDS 342 F
1
Revision 090704
Integrated Circuit Systems, Inc. ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com