SI5347-EVB Datasheet, PDF (7/21 Pages) Silicon Laboratories – Powered from USB port or external

Si5347-EVB
7. Clock Input Circuits (INx/INxB)
The Si5347-EVB has eight SMA connectors (IN0-IN0B—IN3./IN3B) for receiving external clock signals. All input
clocks are terminated as show in Figure 5 below. Note input clocks are AC coupled and 50  terminated. This
represents 4 differential input clock pairs. Single-ended clocks can be used by appropriately driving one side of the
differential pair with a single-ended clock. For details on how to configure inputs as single-ended, please refer to
the Si5347 data sheet.
Figure 5. Input Clock Termination Circuit
8. Clock Output Circuits (OUTx/OUTxB)
Each of the sixteen output drivers (8 differential pairs, OUT0/OUT0B—OUT7/OUT7B) is ac coupled to its
respective SMA connector. The output clock termination circuit is shown in Figure 6 below. The output signal will
have no dc bias. If dc coupling is required, the ac coupling capacitors can be replaced with a resistor of appropriate
value. The Si5347-EVB provides pads for optional output termination resistors and/or low frequency capacitors.
Note that components with schematic “NI” designation are not normally populated on the Si5347-EVB and provide
locations on the PCB for optional dc/ac terminations by the end user.
Figure 6. Output Clock Termination Circuit
Rev. 1.1
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