Issue link: https://iconnect007.uberflip.com/i/1496727
64 DESIGN007 MAGAZINE I APRIL 2023 the unique properties of flexible substrates and combined flexible and rigid substrates, flexible designs require a specific collection of analysis both functional and manufacture oriented. Signal integrity analysis such as impedance, coupling, crosstalk and noise is complicated by variable stackups across flexible designs. A sin- gle transmission line can be stripline in a rigid- flex area and microstrip in a flex area. Material types and dielectric constants above or below a trace as it traverses a design also vary. While the challenges for signal integrity analysis for flexible designs is worthy of conversation, this article will focus on the current challenges to design-for-manufacture analysis of flex and rigid-flex designs. Article by Mark Gallant DOWNSTREAM TECHNOLOGIES Introduction Flex and rigid-flex PCB constructions are not new concepts. It has become commonplace as engineers look for alternative circuit packag- ing for ever-shrinking electronic products. A flat, one-sheet schematic for a straight ribbon cable is analogous to its physical flat substrate. A flat, multi-sheet schematic that details cir- cuitry for a rigid-flex design bears little visual resemblance to its three-dimensional, variable material rigid-flex assembly. However, in both schematic examples, schematic-based analysis tools are applied equally. is same truth also applies to common FR-4-based two-layer or multilayer PCBs. Today's PCB analysis tools are applicable across all combinations of rigid PCBs regard- less of layer count or size. However, due to DFM Analysis for Flex and Rigid-flex Design, Part 1