Via to Trace Clearance: The Clearance Rules Multilayer PCBs Need Routing a multilayer board is mostly an exercise in deciding where copper belongs. Traces carry the signal, planes carry the return current, and vias stitch the two together. What gets far less attention is the space that must be left…

High Frequency Traces and Data Buses: Layout Rules Almost every layout guide repeats the same advice: keep digital and analogue grounds separate. Anyone who has laid out a real board knows how difficult that is to achieve in practice, and the reason is that the advice describes a conclusion rather…

High-Speed PCB Simulation: Three Design Strategies Teams solving the same physics problem arrive at very different places, and the difference is rarely engineering skill. In telecom, computing and imaging, high-speed boards are designed to three distinct postures, and understanding which one a design has fallen into is often the first…

Balanced Stackup: Why an Odd Layer Count Costs More Sooner or later a designer ends up with a stack that needs an odd number of layers. If the routing does not require another layer, why add one? A thinner board should be cheaper, and one fewer layer should cost less.…

Motor Driver PCB Design: Layout and Thermal Rules A motor driver is a power design wearing a logic design’s clothes. It receives low-level control signals, and it delivers currents that are large enough to destroy traces, cook devices and corrupt the ground reference of everything else on the board. Designing…

ESD on PCB Edge Traces: Why It Happens Electrostatic discharge testing produces some of the most instructive failures in board design, because the symptom and the cause are rarely in the same place. A product can pass every functional test and still reset during a contact discharge applied to its…

Metal Core PCB: Base Materials, Types and Properties Not every board is built on FR-4. Where a design has to move serious amounts of heat, or where a circuit must be shielded and mechanically robust at the same time, a metal core PCB becomes the practical choice. The construction looks…

Copper Pour on PCB Outer Layers: Benefits and Conditions Pouring copper across the outer layers is one of the easiest steps to skip when a design is running late, and one of the easiest to justify afterwards. The question is whether the omission costs anything. Outer-layer copper pour is both…

HDI Board CAM: Pads, Non-Functional Pads and Laser Vias High density interconnect exists to serve highly integrated devices and dense assembly requirements, and it pushed board fabrication onto a new level of difficulty. Among all the CAM work a shop undertakes, an HDI board for a phone platform is considered…

Thixotropy in Solder Mask Ink for Screen Printing Ink is one of the essential consumables of board fabrication, and how it behaves decides the technical and quality parameters of the finished product. Manufacturers therefore pay close attention to ink performance — and almost all of that attention goes to viscosity.…