Optimizing X2Y Performance with Proper Attachment Techniques

X2Y® capacitors excel in low inductance performance for a myriad of applications including EMI/RFI filtering, power supply bypass / decoupling. How the capacitor is attached to the application PCB is every bit as important as the capacitor itself. Proper attention to pad layout and via placement insures superior device performance. Poor PCB layouts squander performance, requiring more capacitors, and more vias to do the same job. Figure 1 compares the X2Y® recommended layout against a poor layout. Because of its long extents from device terminals to vias, and the wide via separation, the poor layout shown performs badly. It exhibits approximately 200% L1 inductance, and 150% L2 inductance compared to recommended X2Y layouts.

For further details on via placement and it’s effect on mounted inductance, please refer to X2Y Attenuators, LLC. application note “Get the Most from X2Y Capacitors with Proper Attachment Techniques”