Board Outline, Slot and Tolerance Rules for PCB Fabrication The mechanical side of a fabrication package is where designs are most often under-specified. The copper layers describe the circuit, but the outline, the slots, the tolerance and the flatness requirement have to be stated explicitly, and where they are not,…

Rogers 4003 PCB: Properties, Design and Cost Guide Rogers 4003, also written RO4003C, occupies a useful middle ground among high frequency laminates. It is a ceramic filled hydrocarbon material rather than a PTFE composite, so it processes much like FR-4 while still delivering a stable dielectric constant and low loss…

PCB Thermal Design: Rules That Move Heat Out of the Board Heat leaves a board by three paths: conduction through copper, conduction through the laminate, and convection or radiation from the surface into the surrounding air. The laminate is the weakest of the three by a wide margin, which is…

Why High-Speed Traces Stay Away From the Board Edge Two rules in high-speed design appear to contradict each other. One says that a high-speed trace should never run along the edge of the board. The other says that an antenna on the board should be placed as close to the…

Six Layer Stackup for an Automotive Infotainment Board A centre console board connects a display, a camera, a radio, a touch panel and the vehicle network, all inside a dashboard that bakes in the sun and hums with electrical noise. A six layer stackup has become the standard answer for…

Reverse Engineering Legacy Hardware into Usable Design Data Reverse engineering a circuit board means reconstructing usable design data from a physical sample. It is a legitimate engineering activity with a long history: legacy equipment that must be supported long after its documentation has been lost, a competitor product that must…

Low Loss Laminate Selection for High Speed PCB Designs Material selection for a high speed board used to be a simple choice between ordinary FR4 and an expensive low loss laminate. With serial links now running at tens of gigabits per second per lane, the decision has become a graded…

IC Substrate and PCB: Structure, Materials and Process An IC substrate and a printed circuit board are made with similar equipment and similar chemistry, and they are often confused in conversation. They are different products with different requirements: a PCB carries components and connects them across a system, while an…

PCB Teardrops: Design Rules and Where They Help A teardrop is a fillet of copper added where a trace joins a pad or a via. It widens the junction gradually instead of meeting the pad at a sharp angle, and that simple change removes the point where a mechanical or…

PCB Design Review Process and Self-Check Items A design review is the cheapest defect removal tool available. A problem found on a schematic or a layout costs a comment, while the same problem found after fabrication costs a panel, a schedule slip and a customer conversation. The purpose of a…