I2SB

ESD Protection in PCB Layout: 6 Practical Guidelines ESD can quietly ruin a robust design. Here are several proven layout practices to keep your electronics safe. 🟡 Optimize impedance around the TVS Every trace has parasitic inductance. In a typical protection path, you’ll find inductance between: ESD source → TVS TVS → GND TVS → protected IC 🔑 Key principle: Make the impedance between TVS and IC higher than the path from the ESD source to the TVS. This forces the surge current into the protection device — not your IC. 🟡 Limit EMI from ESD pulses Fast voltage transitions from ESD can radiate strong EMI. Nearby traces act like antennas or capacitive couplers, spreading energy into other circuits. ✅ How to reduce coupling: Isolate protection areas from sensitive signals Don’t route unprotected signals near ESD paths Use short, direct traces Avoid sharp routing angles 🟡 Use vias carefully Vias add inductance. If your signal path from the ESD source to the IC includes vias before the TVS, some ESD energy may bypass protection. 👉 Best practice: Keep the ESD source and TVS on the same layer. Avoid vias between them — ensure the ESD current hits the TVS first. 🟡 Place the ESD suppressor properly Position the TVS as close as possible to the ESD entry point (USB, HDMI, Ethernet, external cables). The goal: intercept the surge immediately. 📌 Golden rule: Connector → TVS → protected IC Order is everything. 🟡 Avoid vias between ESD source and suppressor (even when unavoidable) If vias can’t be avoided, be extra careful. Wrong routing can steer ESD current toward the IC before reaching the TVS. A better compromise: Keep the TVS directly in the signal path Place the protected circuit downstream of the suppressor 🟡 Provide proper grounding A TVS is only as good as its ground connection. High-impedance ground kills clamping performance. ✅ Recommended: Connect TVS directly to the ground plane Use multiple ground vias Keep the ground path short and wide This creates a low-impedance path for safe ESD dissipation.