Design007 Magazine

98 DESIGN007 MAGAZINE I DECEMBER 2021 Challenges in Simulating a Wirebonded CoB on a Rigid-Flex PCB ere are many good reasons to use a chip- on-board (CoB) implementation. When this is combined with wirebonding and the use of a rigid-flex PCB, challenges mount. An applica- tion that demands all three—CoB, wirebond- ing, and rigid-flex PCB—is a camera module that goes into a mobile application, the sample design used to illustrate the design and analysis challenges in this article. If you are not aware of and prepared for the potential pitfalls, it is highly likely that your project could fall short or even fail. If the camera module goes into a mobile application, cost, performance, footprint (in all three axes), and time to market become requirements that must be met. Cost and foot- print justify the use of CoB implementation due to the elimination of a package; perfor- mance and cost justify the wirebonding of the image sensor die directly on to a rigid-flex PCB, since the short wires with the eliminated pack- age improve performance and reduce cost; the restricted footprint within a mobile device calls for the use of a rigid-flex PCB. Figure 1 shows a rigid-flex PCB with an image sensor imple- mented using CoB and the MIPI signals driven to the connector on the other end of the rigid- flex PCB. e impedance of the MIPI signals traversing from the wirebonded chip to the connector must be a consistent 100-Ohm path. All Systems Go! by Brad Griffin, CADENCE DESIGN SYSTEMS, INC. Figure 1: Rigid-flex PCB with CoB and connector.

• December 2021 — Design007 Magazine
• Feature Contents — The Art and Science of PCB Design
• Additional Contents
• Flex007 Contents
• Column — The Art of PCB Design: I Know It When I See It
• Feature Interview — PCB Design: Where Art and Science Intersect
• Column — 'Dealing' With PCB Design
• Feature Article — Will AI Replace the Art of PCB Design?
• Column — The Rise of Resin in IoT Applications
• Column — Leveraging Digital Twins to Optimize Electronic Systems
• Feature Interview — Field of Dreams: The Art and Science of Designing with Field Theory
• Article — Test and Inspection
• Feature Article — The Colorful World of PCB Design
• PCB007 Highlights
• Feature Article — The Art of Using Symmetry—and Asymmetry—in PCB Design
• Column — Best Practices for Solder Mask Application
• Column — High-Performance 3D Printed Circuitry
• Feature Interview — The Art and Science of DFM
• Feature Interview — The Art and Science of PCB Design—You Are the Best Tool
• Feature Column — Creative Minds Pushing Boundaries
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• Column — Live or via Zoom, Knowledge Is All Around Us
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• Short — Navigating the Supply Chain Storm With ICAPE
• Article — RealTime with… American Standard Circuits: Thermal Management
• Feature Article — Revving Up Design
• Flex007 Column — Shaping Flexible Circuits
• Flex007 Short — Elementary, Mr. Watson: We've Never Done It That Way Before
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• Flex007 Column — Challenges in Simulating a Wirebonded CoB on a Rigid-Flex PCB
• Flex007 Short — Flexible, Wearable X-ray Detector Doesn't Require Heavy Metals
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