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58 DESIGN007 MAGAZINE I OCTOBER 2018 tions developed for surface mounting, but as previously noted, due to the excessive height of components greater than 0402, they may not be a good option for embedding without extending the cavity further into upper circuit layers. Dielectric working voltages and value ranges for the smaller capacitor outlines may be somewhat limited, and manufacturers warn that ceramic multilayer capacitors, if not prop- erly positioned, can be prone to cracking. To minimize physical stress designers, design- ers are advised to position capacitors with a standard orientation within the embedded substrate structure. For the larger resistor com- ponents, thinner components will usually not need special attention when laminating circuit layers. However, the higher profile component will require that the PCB fabricator modify the copper on the circuit layer directly above the capacitor to create a cavity in the prepreg material around the component's perimeter (Figure 3). 1 Prepreg and copper foil material slightly larger than the component outline must be removed before lamination. Small outline inductors are also available from limited sources with values ranging up to 100 nH. There are currently only two types of discrete inductor types that are suitable for embedding into the PCB: multilayer ceramic and thin-film multilayer on ceramic. Multilayer ceramic and thin-film inductor products have a relatively small outline, but their thickness Figure 3: Embedding discrete passive capacitor elements. Table 4: Multilayer inductor.