DATASHEET
SERIAL PROGRAMMABLE TRIPLE PLL SS VERSACLOCK SYNTH
ICS309
Description
Features
The ICS309 is a versatile serially-programmable, triple
PLL with spread spectrum clock source. The ICS309
can generate any frequency from 250kHz to 200 MHz,
and up to 6 different output frequencies simultaneously.
The outputs can be reprogrammed on-the-fly, and will
lock to a new frequency in 10 ms or less.
• Packaged in 20-pin SSOP (QSOP) – Pb-free, RoHS
compliant
• Highly accurate frequency generation
•M/N Multiplier PLL: M = 1..2048, N = 1..1024
• Serially programmable: user determines the output
frequency via a 3-wire interface
To reduce system EMI emissions, spread spectrum is
available that supports modulation frequencies of
31 kHz and 120 kHz, as well as modulation amplitudes
of +/-0.25% to +/-2.0%. Both center and down-spread
options are available.
• Spread Spectrum frequency modulation for reduced
system EMI
•Center or Down Spread up to 4% total
•Selectable 32 kHz and 120 kHz modulation
• Eliminates need for custom quartz oscillators
• Input crystal frequency of 5 - 27 MHz
• Input clock frequency of 3 - 50 MHz
• Output clock frequencies up to 200 MHz
• Operating voltage of 3.3 V
The device includes a PDTS pin which tri-states the
output clocks and powers down the entire chip.
The ICS309 default for non-programmed start-up are
buffered reference clock outputs on all clock output
pins.
TM
IDT’s VersaClock programming software allows the
user to configure up to 9 outputs with target
• Up to 9 reference clock outputs
• Power down tri-state mode
frequencies, spread spectrum capabilities or buffered
TM
reference clock outputs. The VersaClock software
automatically configures the PLLs for optimal overall
performance.
• Very low jitter
Block Diagram
3
VDD
PLL1 with
Spread
CLK1
CLK2
CLK3
CLK4
CLK5
CLK6
CLK7
CLK8
CLK9
STROBE
Spectrum
SCLK
DATA
Divide
Logic
and
Output
Enable
Control
PLL2
PLL3
Crystal or
clock input
X1/ICLK
Crystal
Oscillator
X2
GND
2
External capacitors are
required with a crystal input.
PDTS
IDT® SERIAL PROGRAMMABLE TRIPLE PLL SS VERSACLOCK SYNTH
1
ICS309
REV L 091311
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
