CLKin and OSCin path ± if differential input (preferred) route traces tightly coupled. If single
ended, have at least 3 trace width (of CLKin/OSCin trace) separation from other RF traces.
When using CLKin1 for high frequency input for external VCO or distribution, a 3 dB pi pad is
suggested for termination.
Place terminations close to IC.
CLKin2 and OSCout share pins and is programmable for input or output.
For CLKout Vccs in JESD204B application, place ferrite beads then 1 µF
capacitor. The 1 µF capacitor supports low frequency SYSREF switching/turn on.
For CLKout Vccs in traditional application place ferrite bead on top layer close to
pins to choke high frequency noise from via.
Charge pump output ± shorter traces are better. Place a
resistors and caps closer to IC except for a single capac
and associated resistor, if any, next to VCXO. In a 2
nd
o
filter place C1 close to VCXO Vtune pin. In a 3
rd
and 4
th
order filter place R3/C3 or R4/C4 respectively close to
VCXO.
CLKouts/OSCouts ± Normally differential signals, shoul
routed tightly coupled to minimize PCB crosstalk. Trace
impedance and terminations should be designed accord
to output type being used (i.e. LVDS, LVPECL, LVCMO
For LVPECL/LCPECL place emitter resistors close to IC
OSCout shares pins with CLKin2 and is programmable
input or output
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