Issue link: https://resources.pcb.cadence.com/i/1541046
27. Avoiding Right-Angle and Acute Trace Corners How To Implement 1. Configure your EDA tool for smooth bends: f Set the routing mode to produce 45° bends (two 45° segments joined) or arcs instead of 90° corners. f Many tools allow you to specify a minimum bend radius or default to "mitered" (beveled) corners. 2. Manually fix any acute or sharp corners: f After auto-routing or complex hand routing, inspect all critical traces (clock, diff pairs, RF, power) for sharp angles or acute turns. f Replace right angles with a pair of 45° bends or use a gentle arc with a radius at least equal to the trace width. f Pay special attention to area fills and ground pours, and auto-fill routines can sometimes create sharp internal corners, which should be rounded off or smoothed. 3. Maintain symmetry in differential pairs: f Ensure both P and N traces in a pair use the same bend style and radius, preserving consistent impedance and skew. 4. Review and correct corners in all layers: f Don't just check the top layer; review all signal and plane layers for sharp transitions, especially where pours or power planes turn corners. 5. Check for potential acid traps: f On very fine traces (<6 mil) or in boards with complex fills, avoid tiny inside angles where etchant can be trapped during manufacturing, as these can create thin spots or open circuits. 6. Automate where possible: f Use your EDA tool's batch "corner smoothing" or "arc conversion" features to clean up all corners in the design before output. Common Pitfalls, Their Impact, and How to Avoid Them Common Pitfall How to Avoid it Trusting autorouter defaults Not all autorouters optimize for signal integrity; manual cleanup is often required – Review and tune autorouter constraints. Leaving corners unreviewed on inner layers or planes Sharp turns here can still create local impedance or acid trap risks – Inspect inner-layer routing and copper shapes for acute angles. Ignoring bend symmetry in diff pairs Causes impedance mismatch and skew – Maintain matched bend geometry for P and N traces. Failing to smooth ground pours and polygons Sharp corners here can concen- trate fields or cause EMI leakage – Use fillets or gentle curves on copper shapes and ground pours.