Si5338-EVB
4
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Rev. 1.5 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • December 14, 2021
5. Inputs
The Si5338-EVB has six SMA connectors (IN1-IN6) for receiving external signals. Two of the signals are
differential, and two are single-ended.
5.1. Differential Inputs (IN1/IN2, IN5/IN6)
The differential inputs only need a differential voltage swing of 300 mV to operate, which makes them compatible
with most differential signal types. See “AN408: Termination Options for Any-Frequency, Any-Output Clock
Generators and Clock Buffers—Si5338, Si5334, Si5330”, or Si5335 data sheet if applicable, for details on
interfacing with compatible signal types. It is also possible to lock the Si5334/35/38 to an external signal generator
using one side of the differential input and grounding its complementary side. Take care not to exceed the max
differential voltage of 1.2 V on these inputs. The board is shipped with a 25 MHz XTAL connected to IN1/IN2. The
XTAL removal and resistor changes are required for Si5335 evaluation with an input clock since only IN1 and IN2
are available for input clocking with Si5335. Note that regardless of device, any external input to IN1 & IN2 must be
limited to 1.2 V peak-to-peak (see Figure 2 for resistor locations). When evaluating the Si5330, the XTAL must be
removed. The differential input on pins IN5/IN6 is ac-coupled with a 100
line termination (R39).
Figure 2. Optional Termination Resistors for Differential Inputs IN1/IN2
5.2. Single-Ended Inputs (IN3, IN4) [Not supported in Si5335]
These inputs are dc-coupled to the device. They are compatible with a signal swing as low as 100 mV and a
maximum of 3.63 V. The signal should have a minimum amount of dc bias to ensure that it is never below ground
level.
The EVB provides pads for optional input terminations. These may be necessary when interfacing to SSTL and
HSTL signals.
Note:
For details on populated vs. non-populated components, refer to "8. Bill of Materials" on page 9.
