ICS849N202I Datasheet, PDF (22/39 Pages) Integrated Device Technology – FemtoClock® NG Universal Frequency Translator

ICS849N202I Data Sheet
FemtoClock® NG Universal Frequency Translator
Applications Information
Recommendations for Unused Input and Output Pins
Inputs:
Crystal Inputs
For applications not requiring the use of the crystal oscillator input,
both XTAL_IN and XTAL_OUT can be left floating. Though not
required, but for additional protection, a 1kΩ resistor can be tied from
XTAL_IN to ground.
CLKx/nCLKx Inputs
For applications not requiring the use of either differential input, both
CLKx and nCLKx can be left floating. Though not required, but for
additional protection, a 1kΩ resistor can be tied from CLKx to ground.
It is recommended that CLKx, nCLKx be left unconnected in
frequency synthesizer mode.
LVCMOS Control Pins
All control pins have internal pullups or pulldowns; additional
resistance is not required but can be added for additional protection.
A 1kΩ resistor can be used.
Outputs:
LVPECL Outputs
All unused LVPECL outputs can be left floating. We recommend that
there is no trace attached. Both sides of the differential output pair
should either be left floating or terminated.
LVDS Outputs
All unused LVDS output pairs can be either left floating or terminated
with 100Ω across. If they are left floating there should be no trace
attached.
LVCMOS Outputs
All unused LVCMOS output can be left floating. There should be no
trace attached.
Recommended Values for Low-Bandwidth Mode Loop Filter
External loop filter components are not needed in Frequency
Synthesizer or High-Bandwidth modes. In Low-Bandwidth mode, the
loop filter structure and components shown in Figure 11 are
recommended. Please consult IDT if other values are needed.
ICS849N202CKI REVISION A SEPTEMBER 26, 2011
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©2011 Integrated Device Technology, Inc.