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26 DESIGN007 MAGAZINE I MARCH 2021 • e edges of the board cause the greatest amount of reflection since an edge is a totally abrupt open circuit. • Reflected energy is accompanied by phase reversals in its components, and combined reflections from the open circuit at the edge of the board can cause a phenomenon known as voltage doubling creating a standing wave. • e larger the plane area, the lower the impedance. • RC terminations of 3R5, in series with 10nF spaced along the board edges, are generally sufficient to reduce the resonance peaks. • e addition of loss to dampen modal resonances is more important than the exact termination value and distribution. • e added losses from the RC terminations are helpful in the overall response of the PDN as they dampen impedance peaks arising from connecting the devices to the board. DESIGN007 Resources 1. Beyond Design: PDN—Decoupling Capacitor Placement, Learning the Curve, Fringing Fields, by Barry Olney, January 2016. 2. Optimized Power Delivery Performance Using Plane Terminations by Istvan Novak, Samtec. 3. US5708400A—AC coupled termination of a printed circuit board power plane in its character- istic impedance—Google Patents, Terrel Morris, Hewlett Packard. Barry Olney is managing director of In-Circuit Design Pty Ltd (iCD), Australia, a PCB design service bureau that specializes in board-level simulation. The company developed the iCD Design Integrity software incorporating the iCD Stackup, PDN, and CPW Planner. The software can be downloaded at To read past columns or contact Olney, click here. Increasing board complexity is driving the need for accurate and speedy inspection systems. In The Printed Circuit Assembler's Guide to SMT Inspection: Today, Tomorrow, and Beyond, author Brent Fischthal takes read- ers through a brief history of SMT inspection before discussing the benefits of data-driven analytics and how intelligent software solutions can help companies analyze and optimize the production process. In this latest title from I-007eBooks, readers will learn how artifi- cial intelligence has demonstrated promising potential in this field and has far-reaching applications within the manufacturing sector. According to Michael Ford, Senior Director of Emerging Industry Strategy for Aegis Software, "This book provides unprecedented visibility of SMT processes, asserting inspection technology as a key active contributor to zero-defect quality initiatives, rather than being limited to simple defect detection." Download your free copy today! New I-007eBook Highlights SMT Inspection: Today, Tomorrow, and Beyond

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