18. TVS Connection

Question.5

Kevin adds a Littelfuse SMBJ5.0A TVS diode on each USB 2.0 data line (D+, D−) for ESD protection.
The USB device fails/ stops connecting . No surge events occurred — the problem is present from power-on.
What went wrong?
Note — Check the capacitance (C_J) from the SMBJ datasheet.

V_RWM = 5V is too low for USB data lines
The TVS is unidirectional — bidirectional is needed for data lines
Junction capacitance (~3500 pF) is far too high — it distorts the USB signal
TVS diodes cannot be used for ESD protection on any data line

Restart quiz!