The optimum placement 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 TVS 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, which increases EMI
coupling.