SI5350C-B Datasheet, PDF (15/31 Pages) Silicon Laboratories – FACTORY-PROGRAMMABLE ANY-FREQUENCY CMOS CLOCK GENERATOR

Si5350C-B
4.5.3. External Crystal
The external crystal should be mounted as close to the pins as possible using short PCB traces. The XA and XB
traces should be kept away from other high-speed signal traces. See “AN551: Crystal Selection Guide” for more
details.
4.5.4. External Crystal Load Capacitors
The Si5350C provides the option of using internal and external crystal load capacitors. If external load capacitors
are used, they should be placed as close to the XA/XB pads as possible. See “AN551: Crystal Selection Guide” for
more details.
4.5.5. Unused Pins
Unused control pins (P0–P3) should be tied to GND.
Unused CLKIN pin should be tied to GND.
Unused XA/XB pins should be left floating. Refer to "2.2. Applying a Reference Clock at XTAL Input" on page 8
when using XA as a clock input pin.
Unused output pins (CLK0–CLK7) should be left unconnected.
4.5.6. Trace Characteristics
The Si5350C features various output drive strength settings. It is recommended to configure the trace
characteristics as shown in Figure 10 when the default high output drive setting is used.
Z_O = 50 ohms
CLK
R = 0 ohms
(Optional resistor for
EMI management)
Figure 10. Recommended Trace Characteristics with Default Drive Strength Setting
Rev. 1.0
15