Common PCB Design Problems That Delay Fabrication and Assembly Most boards that come back from fabrication with a query, or from assembly with an unexpected defect, are not failing because of an exotic mistake. They are failing because of a small set of familiar issues that are easy to introduce…

Electrical Test in PCB Production: Opens, Shorts and Fixtures A bare board that passes visual inspection can still contain a broken track inside a via, a short between two inner layers, or a connection that is marginal enough to fail in the field. Electrical test is the only step in…

SMT vs Through-Hole Components for PCB Assembly Every board carries a mix of surface-mount and through-hole parts, and the split is usually decided by habit rather than by analysis. Both families are mature, and the right choice depends on which property matters most for that net: density, thermal path, mechanical…

PCB Layout Component Spacing Rules and Twelve Practical Checks Most assembly problems that reach the production line were decided months earlier on the layout screen. A part placed 0.1 mm too close to its neighbour turns a normal stencil print into a bridging defect; a thermal pad connected to a…

PCB Design Factors: Layers, Vias, Silkscreen and Pads Most layout problems trace back to a handful of concepts that are easy to use without understanding. A pad that was placed as a default, a via that was copied across the board, a copper pour that was drawn as a rectangle…

Cold Solder Joint Prevention: Flux, Tip Temperature and Pad Cleanliness Hand soldering looks simple until a board comes back from test with an intermittent connection that disappears when the probe touches it. Almost every one of those failures is a cold solder joint, or its close relative the false joint,…

EMC Design for Switching Power Supply PCB Layout Switching supplies are among the most demanding boards to lay out for electromagnetic compatibility, because the interference is generated by the circuit’s normal operation rather than by a fault. Currents and voltages change rapidly by design, the switching node is a small…

Signal Integrity Design for Gigabit PCB Interconnects Gigabit links moved high-speed design out of the laboratory and onto ordinary backplanes and line cards, and with that move the assumptions that had served at lower rates stopped holding. A trace that was previously treated as a wire now behaves as a…

PCB Fabrication Processes: Subtractive, Additive, and Semi-Additive Every printed circuit board is produced by one of three basic strategies: material is removed to leave conductors, material is added until conductors exist, or the two approaches are combined. Which one a fabricator uses determines the achievable line width, the panel cost,…

Component Placement: Using the Ratsnest as a Guide Component placement is often treated as the stage before the real work, and then the real work turns out to be impossible. Designers recognise the experience: a few connections remain, no path exists for them, and the only way forward is to…