EDI CON Online
Title: Power Integrity: Layer Stackup and Decoupling to Achieve a Target Impedance
Date: August 25, 2021
Time: 7:30am PT / 10:30am ET
Presented by: Jim Drewniak, President, Clear Signal Solutions
There are many choices in PCB power integrity design to achieve a specified voltage ripple, or target impedance. For the power net, this includes on which layer(s) to locate it, spacing between the power net and closest ground, and special materials for embedded capacitance. For decoupling, design choices include capacitor location, value(s), interconnect geometry, and total number needed. Typically, PI design is also constrained by high-speed routing considerations to avoid any compromise of routing flexibility. This often prohibits optimizing choices for minimizing inductance in the PI design process. This session begins with a brief overview of the inductance physics and relationship to the current path from the decoupling capacitors to the IC package. Then, it covers the relationship of each inductance piece to the power distribution network impedance. Finally, it presents a systematic approach for determining a layer stackup and a decoupling solution addressing typical design choices.
Jim Drewniak received B.S., M.S., and Ph.D. degrees in electrical engineering from the University of Illinois at Urbana-Champaign. He was a Curator’s Professor of Electrical and Computer Engineering with the Electromagnetic Compatibility Laboratory in the Electrical Engineering Department at the Missouri University of Science and Technology. His research and teaching interests focused on electromagnetic compatibility in high-speed digital and mixed-signal designs, signal and power integrity, and electronic packaging. After 28 years with the university, he retired and founded Clear Signal Solutions, a company providing measurement and characterization solutions for signal and power integrity applications. He is a Fellow of the IEEE, and recipient of the 2013 Richard R. Stoddart Award, the IEEE Electromagnetic Compatibility Society’s highest award for technical achievement. He has taught short courses widely for industry on signal and power integrity, and EMI.