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52 DESIGN007 MAGAZINE I OCTOBER 2018 This column will focus on land pattern devel- opment criteria, and methodology for accom- modating low and moderately high-profile pas- sive components within a multilayer circuit board. As noted in Part 3 of this series, a broad range of discrete passive component elements are candidates for embedding, but the decision to embed these component elements within the multilayer circuit structure must be made early in the design process. While many of these components are easy candidates for integrating into the substrate, others may not be suitable, or they are difficult to rationalize because they involve more complex process methodology. Substrate Development Basic material sets selected for this embed- ded component application defines a 200-μm FR-4 epoxy-glass core base with 18-μm copper foil bonded to both sides. In this example, the buildup material includes pre-impregnated lay- ers of glass cloth with an uncured epoxy resin furnished pre-dried, but not hardened, and lay- ers of 18-μm copper foil. There are more than a dozen thickness options available for prepreg materials, but for this process description, a 200-μm material will be referenced. The pre- preg layer and copper foils are sequentially bonded together using a combination of pres- sure and heat. The process begins with imag- Embedding Components, Part 4: Passive Component Selection and Land Pattern Development Designers Notebook by Vern Solberg, CONSULTANT