Because ESD transients have a wide frequency
bandwidth from approximately 3MHz to 3GHz, high-frequency layout techniques must be
applied during PCB design.
- Use VCC and ground planes to provide low inductance. High frequency currents follow the path of least inductance and not the path of least impedance.
- Apply 100nF to 220nF bypass capacitors as close
as possible to the VCC pins of transceiver, UART, or controller ICs
on the board.
- Use at least two vias for VCC and ground connections of bypass capacitors to minimize effective via-inductance.
- Use 1kΩ to 10kΩ pullup or pulldown resistors for
enable lines to limit noise currents in these lines during transient
events.