SMARC T335x Carrier Board Hardware Design Guide, Document Revision 1.2
2.3.2.3. USB Client Considerations
Precautions at the carrier board level must be taken to protect against
voltage spikes and
ESD
to ensure robust operation of the host detection
circuitry after multiple connect/disconnect events. A clamping diode may
be used to minimize
ESD
, and a bulk capacitor should be placed on +5V
USB client rail to avoid excessive voltage spikes.
This will protect the level-shifting circuitry on the
USB0_VBUS_DET
signal
used to alert the
SMARC
module's internal USB client controller when a
host device is present.
Figure 14: USB Client Consideration