SLLSEE5D february 2013 – july 2023 TUSB8040A1
PRODUCTION DATA
The TUSB8040A1 accepts a crystal input to drive an internal oscillator or an external clock source. If a clock is provided to XI instead of a crystal, XO is left open and VSSOSC should be connected to the PCB ground plane. Otherwise, if a crystal is used, the connection needs to follow the guidelines below. Since XI and XO are coupled to other leads and supplies on the PCB, it is important to keep them as short as possible and away from any switching leads. It is also recommended to minimize the capacitance between XI and XO. This can be accomplished by connecting the VSSOSC lead to the two external capacitors CL1 and CL2 and shielding them with the clean ground lines. The VSSOSC should not be connected to PCB ground when using a crystal.