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SI5342-EVB Datasheet, PDF (6/18 Pages) Silicon Laboratories – Powered from USB port or external power supply | |||
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Si5342-EVB
6. Clock Input Circuits (INx/INxB)
The Si5342-EVB has eight SMA connectors (IN0/IN0BâIN3/IN3B) for receiving external clock signals. All input
clocks are terminated as shown in Figure 4 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 Si5342 data sheet. Typically a 0.1 ïF DC block is sufficient, however, 10 ïF may be needed for lower input
frequencies. Note that the EVB is populated with both DC block capacitor values.
Figure 4. Input Clock Termination Circuit
7. Clock Output Circuits (OUTx/OUTxB)
Each of the four output drivers (2 differential pairs) is AC coupled to its respective SMA connector. The output clock
termination circuit is shown in Figure 5 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 Si5342-EVB provides an
L-network at OUT0/OUT0B output pins for optional output termination resistors. Note that components with
schematic âNIâ designation are not normally populated.
Figure 5. Output Clock Termination Circuit
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Rev. 1.0
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