ICS309
SERIAL PROGRAMMABLE TRIPLE PLL SS VERSACLOCK SYNTHESIZER
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)
• 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
• Spread Spectrum frequency modulation for reduced
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.
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
ICS’ VersaClock programming software allows the
• Up to 9 reference clock outputs
• Power down tri-state mode
user to configure up to 9 outputs with target
frequencies, spread spectrum capabilities or buffered
TM
reference clock outputs. The VersaClock software
• Very low jitter
automatically configures the PLLs for optimal overall
performance.
Block Diagram
3
VDD
PLL1 with
Spread
Spectrum
CLK1
CLK2
CLK3
CLK4
CLK5
CLK6
CLK7
CLK8
CLK9
STROBE
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
MDS 309 G
1
Revision 122704
Integrated Circuit Systems ● 525 Race Street, San Jose, CA 95126 ● tel (408) 297-1201 ● www.icst.com