SDRAM Radiation: Layout Rules for External Memory External memory is one of the most common sources of radiated emissions on a microcontroller board, and it is one of the most fixable. A parallel SDRAM bus runs at a high clock rate with fast edges, and its traces carry the same…

High Precision PCB Manufacturing: Fine Lines and Microvias Density on a printed circuit board is increased by making conductors narrower and holes smaller, and both changes push the process into a region where tolerance, not capability, becomes the limiting factor. A board shop that can hold a 0.20 mm line…

Backplane and Modular Structures in Industrial Control PCB Design An industrial controller can be built as one large board or as a set of smaller boards that plug into a common backplane, and the choice between backplane and modular structures is usually made early, because it determines the mechanical design,…

Metal Core PCB Design and Fabrication Basics When a board has to move heat rather than carry signals, ordinary FR-4 stops being the right material. A metal core PCB replaces the usual insulating base with aluminium or copper, separated from the circuit by a thin dielectric that conducts heat but…

PCBA Production Flow from Bare Board to Finished Assembly A bare printed circuit board becomes a functional assembly through a sequence of steps that each add material, components or information. The sequence matters because the order is fixed by physics: paste must be printed before parts are placed, parts must…

Resistor Selection in Circuit Board Design A resistor is the simplest component on the board and the one most often chosen without thought. The value is calculated, a familiar part number is reached for and the design moves on. That habit works until a circuit drifts at temperature, a part…

PCB Immersion Gold Versus Hard Gold: Design, Process, and Quality Notes Buyers and engineers often focus on the finished product and forget the production line behind it. In practice, most field failures can be traced back to process decisions made during assembly. Understanding PCB immersion gold versus hard gold gives…

PCB Hard Gold for Edge Connectors: Metal That Survives Insertion Electronics manufacturing has become a discipline of small details. Solder paste volumes, placement accuracy, temperature profiles and inspection limits all add up to the final result. This guide looks at PCB hard gold for edge connectors from the perspective of…

EMC Design Principles: Loop Area, Grounding and Stackup Electromagnetic compatibility is often presented as a list of prohibitions, which makes it hard to remember and harder to apply. The underlying physics is much smaller: current radiates, loop area determines how efficiently, and common mode current is what leaves the board…

PCB Safety Spacing: Electrical and Non-Electrical Gaps Spacing rules are the part of a design rule set that gets the least attention and causes the most avoidable rework. Most of them are not electrical at all; they exist because the fabricator needs room to etch, the assembler needs room to…