S i 5 3 4 5 - E V B
6
Rev. 1.1
7. Clock Input Circuits (INx/INxB)
The Si5345-EVB has eight SMA connectors (IN0, IN0B–IN3, IN3B) for receiving external clock signals. All input
clocks are terminated as shown in Figure 5 below. Note input clocks are AC coupled and 50 ohm 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 Si5345 data sheet.
Figure 5. Input Clock Termination Circuit
8. Clock Output Circuits (OUTx/OUTxB)
Each of the twenty output drivers (10 differential pairs) 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 Si5345-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 Si5345-EVB and provide locations on the PCB for
optional DC/AC terminations by the end user.
Figure 6. Output Clock Termination Circuit
