Calculate voltage drop across PCB traces based on geometry and current.
| Application | Max Drop | Notes |
|---|---|---|
| Digital Logic (3.3V) | <100 mV (3%) | Stay within spec margins |
| Sensitive Analog | <50 mV (1-2%) | Critical for ADC/DAC |
| Power Rails | <150 mV (3-5%) | Depends on regulator dropout |
| LED Circuits | <500 mV | Less critical |
| Motor/High Power | <1V | Use copper pours or bus bars |
Every PCB trace has electrical resistance. When current flows through this resistance, it creates a voltage drop (V = I × R) and power loss (P = I² × R).
Doubling trace width cuts resistance in half. Use the maximum width your layout allows for power traces.
2 oz copper has half the resistance of 1 oz. Consider 2-4 oz for power layers.
Place power components close to their sources. Minimize routing distance for power rails.
Use power planes or polygon pours instead of traces for high-current paths.
Generally, keep drop under 3-5% of your supply voltage. For 3.3V logic, that's about 100-165mV. Sensitive analog circuits may need tighter control (<1%).
No, the trace width calculator focuses on thermal limits (current carrying capacity). A trace might be thermally adequate but have excessive voltage drop for your application. Check both.
Usually not needed for digital signals (low DC current). Focus on power rails and high-current paths. For analog signals, consider ground return path resistance too.