The
TUSB2514B accepts a 24MHz crystal input or an external clock source to drive an
internal oscillator. If a clock is provided to XI instead of a crystal, XO is left open.
Otherwise, if a crystal is used, the connection must follow the guidelines below. The XI and
XO are coupled to other leads and supplies on the PCB. Keep the XI and XO as short as possible
and away from any switching leads. TI also recommends minimizing the capacitance between XI
and XO by shielding CL1 and CL2 with the clean ground lines.