ICS307
Serially Programmable Clock Source
Description
The ICS307-01 and ICS307-02 are versatile
serially programmable clock sources which take
up very little board space.
They can generate any frequency from 6 to
200 MHz, and have a second configurable
output. The outputs can be reprogrammed on
the fly, and will lock to a new frequency in 10 ms
or less. Smooth transitions (in which the clock
duty cycle remains roughly 50%) are guaranteed
if the output divider is not changed.
The devices include a PDTS pin which tri-states
the output clocks and powers down the entire
chip.
The ICS307-02 features a default clock output
at start-up and is recommended for all new
designs.
Features
• Packaged as 16 pin narrow SOIC
• Highly accurate frequency generation
• Serially programmable: user determines
the output frequency via a 3 wire interface.
• Eliminates need for custom quartz
• Input crystal frequency of 5 - 27 MHz
• Output clock frequencies up to 200 MHz
• Power Down Tri-State mode
• Very low jitter
• Operating voltages of 3.0 to 5.5 V
• 25 mA drive capability at TTL levels
• Industrial temperature available
Block Diagram
TTL
2
Shift
Register
3
2
R6:R0
7
VDD GND
SCLK
DATA
STROBE
C1:C0
S2:S0
F1:F0
9
V8:V0
Output
Buffer
VCO
Divider
S2:S0
3
VCO
Output
Divider
PDTS
CLK1
Crystal or
clock input
X1/ICLK
Reference
Divider
Phase Comparator,
Charge Pump,
and Loop Filter
Crystal
Oscillator
X2
Function
Select
2
F1:F0
Output
Buffer
TTL
CLK2
C1:C0
MDS 307 D
1
Revision 042501
Integrated Circuit Systems, Inc. • 525 Race Street • San Jose •CA•95126•(408) 295-9800tel •www.icst.com
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