ICS307-01/-02
SERIALLY PROGRAMMABLE CLOCK SOURCE
SER PROG CLOCK SYNTHESIZER
Determining the Output Frequency
On power-up, the ICS307-01 on-chip registers can have
random values so almost any frequency may be output
from the part. CLK1 will always have some clock signal
present, but CLK2 could possibly be OFF (low).
The ICS307-02 on-chip registers are initially configured
to provide a x1 output clock on both the CLK1 and CLK2
outputs. The output frequency will be the same as the
input clock or crystal. This is useful if the ICS307 will
provide the initial system clock at power-up. Since this
feature is an advantage in most systems, the
ICS307-02 is recommended for new designs.
With programming, the user has full control in changing
the desired output frequency to any value over the
range shown in Table 1 on page 4. The output of the
ICS307 can be determined by the following equation:
And for the industrial temperature range:
VDW + 8
60MHz
<
InputFrequency
⋅
2
⋅
------------------------ < 360MHz
RDW + 2
Input Frequency
200kHz < ------------------------------------------
-
RDW + 2
To determine the best combination of VCO, reference,
and output dividers, see the online calculator at
www.idt.com
or contact IDT by sending an e-mail to
ics-mk@icst.com with the desired input crystal or clock
and the desired output frequency.
VDW + 8
-
CLK1Frequency
=
InputFrequency
⋅
2
⋅
---------------------------------------------
(
RDW
+
2
) ⋅
OD
Where:
VCO Divider Word (VDW) = 4 to 511 (0, 1, 2, 3
are not permitted)
Reference Divider Word (RDW) = 1 to 127 (0 is
not permitted)
Output Divider = values on page 4
The following operating ranges should be observed. For
the commercial temperature range:
VDW + 8
55MHz
<
InputFrequency
⋅
2
⋅
------------------------ < 400MHz
RDW + 2
InputFrequency
-
200kHz
<
---------------------------------------------
RDW
+
2
IDT™ / ICS™
SERIALLY PROGRAMMABLE CLOCK SOURCE
3
ICS307-01/-02 REV H 090209
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
