Proper routing and placement is important to maintain the signal integrity the SBU and CC line signals. The following guidelines apply to the TPD4S311:
- Place the bypass capacitors as close as possible to the VPWR pin, and ESD protection capacitor as close as possible to the VBIAS pin. Capacitors must be attached to a solid ground. This minimizes voltage disturbances during transient events such as short-to-VBUS and ESD strikes.
- The SBU lines must be routed as straight as possible and any sharp bends must be minimized.
Standard ESD recommendations apply to the C_CC1, C_CC2, C_SBU1, C_SBU2:
- The optimum placement for the device is as close to the connector as possible:
- EMI during an ESD event can couple from the trace being struck to other nearby unprotected traces, resulting in early system failures.
- The PCB designer must minimize the possibility of EMI coupling by keeping any unprotected traces away from the protected traces which are between the TPD4S311 and the connector.
- Route the protected traces as straight as possible.
- Eliminate any sharp corners on the protected traces between the TVS and the connector by using rounded corners with the largest radii possible.
- Electric fields tend to build up on corners, increasing EMI coupling.