Does Decoupling Capacitor Placement Actually Matter?

Altium Develop gives your whole team real-time visibility into PCB designs, BOMs, and supply chain data so you can make smarter layout decisions faster: https://www.altium.com/develop?utm_source=youtube&utm_medium=video&utm_campaign=signal-integrity&utm_content=does-decoupling-capacitor-placement-actually-matter Does decoupling capacitor placement actually matter on your PCB? It's a question that's sparked serious debate among engineers — and a viral LinkedIn post by Rolf Ostergaard citing a 1995 IEEE paper by Dr. Todd Hubing reignited the conversation. In this video, Zach Peterson digs into the claim that capacitor location is largely irrelevant on multilayer boards with proper power and ground planes, and adds the critical context that most application notes leave out. The answer, as it turns out, depends heavily on your board stackup and component package. Zach walks through the math on spreading inductance vs. trace inductance, compares trace-routed and plane-connected decoupling scenarios, and explains exactly when the "place caps as close as possible" rule applies — and when it simply doesn't. Whether you're working with BGAs or flat pack components, this video gives you the engineering foundation to make informed decoupling decisions on your next design. 👉 Resources from this Video: - Rolf Østergaard's post: https://www.linkedin.com/posts/rolfostergaard_pcbdesign-powerintegrity-signalintegrity-activity-7440428255796477955--50l/ - EMC Expert Debunks Common PCB Grounding Myths (with Todd Hubing): https://youtu.be/7PJGPDiA31Q - Dr. Todd Hubing's IEEE paper: https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=2210&context=ele_comeng_facwork -How Do Pads and Vias Impact Total Capacitor Parasitic Inductance? (by Kella Knack): https://resources.altium.com/p/how-do-capacitor-mounting-structures-and-footprints-impact-total-inductance 💡 Stay Connected: Don't forget to like, comment, and subscribe for more in-depth tutorials and tips from @AltiumAcademy! Share your thoughts and questions in the comments below! 👉 Subscribe for more: https://www.youtube.com/@AltiumAcademy?sub_confirmation=1 Don't forget to follow us on social to stay up-to-date on the latest Altium Academy content. 👉 Follow Altium on TikTok: https://www.tiktok.com/@altiumdesigner 👉 Follow Altium on Twitter: https://twitter.com/altium 👉 Follow Altium on Linkedin: https://www.linkedin.com/company/altium/ 👉 Follow Altium on Facebook: https://www.facebook.com/AltiumOfficial/ The Altium Academy is an online experience created to bring modern education to PCB Designers and Engineers all across the world. Here you can access a vast library of free training and educational content covering everything from basic design to advanced principles and step-by-step walkthroughs. Join industry legends as they share their career knowledge, review real-life design projects, or learn how to leverage one of Altium's leading design tools. No matter your level of experience, the Altium Academy can help you become a better Designer and Engineer! About Altium LLC Altium LLC (ASX:ALU), a global software company based in San Diego, California, is accelerating the pace of innovation through electronics. From individual inventors to multinational corporations, more PCB designers and engineers choose Altium software to design and realize electronics-based products. #Altium #SignalIntegrity #PCBDesign 0:00 Intro 2:15 Comments on Decoupling Caps 6:41 Dr. Hubing's Remarks Summary ️ 7:45 IEEE Paper Investigation 09:27 Capacitor Placement Evidence 11:28 Trace Inductance Analysis 15:17 Spreading Inductance Role 17:13 Power & Ground Planes Impact 18:25 Controversies & Conclusion