Robust and reliable bus node design often requires the use of external transient protection devices to protect against surge transients that may occur in industrial environments. Since these transients have a wide frequency bandwidth (from approximately 3MHz to 300MHz), high-frequency layout techniques should be applied during PCB design.

1. Place the protection circuitry close to the bus connector to prevent noise transients from propagating across the board.
2. Use V_CC and ground planes to provide low inductance. Note that high-frequency currents tend to follow the path of least impedance and not the path of least resistance.
3. Place F_SET components near the pin to keep capacitance load below recommended value
4. Use a pull up or down resistor on mode to set a default state
5. Apply 100nF to 220nF decoupling capacitors as close as possible to the V_CC pins of transceiver, UART and/or controller ICs on the board.
6. Use at least two vias for V_CC and ground connections of decoupling capacitors and protection devices to minimize effective via inductance.
7. Use 1kΩ to 10kΩ pull-up and pull-down resistors for enable lines to limit noise currents in these lines during transient events.
8. Insert pulse-proof resistors into the A and B bus lines if the TVS clamping voltage is higher than the specified maximum voltage of the transceiver bus pins. These resistors limit the residual clamping current into the transceiver and prevent it from latching up.
9. While pure TVS protection is sufficient for surge transients up to 1kV, higher transients require metal-oxide varistors (MOVs) which reduce the transients to a few hundred volts of clamping voltage, and transient blocking units (TBUs) that limit transient current to less than 1mA.