SMT Assembly Inspection: SPI, AOI and X-Ray Checks Explained Inspection in a modern SMT assembly line is not a final gate that sorts good boards from bad ones. It is a set of measurements placed at each stage of the process, so that a deviation is caught where it is…

Automotive PCB Layout for Functional Safety and EMC An automotive board is not a consumer board with a wider temperature rating. The environment imposes vibration, thermal cycling across a range that spans a winter cold start and a car parked in summer sun, and a service life measured in a…

Surface Finish for Lead-Free Boards and Test Contact A surface finish has to do two jobs that are often discussed separately. It has to keep the copper solderable until the assembly is built, and it has to present a surface that a test probe can penetrate reliably. Moving to a…

High Speed Clock PCB Design: Jitter, Impedance and Routing Every synchronous system has one net that matters more than the rest. The clock sets the instant at which everything else is sampled, so a small error on that net becomes an error everywhere. High speed clock routing is therefore less…

Solder Mask Bridge: Design and Manufacturing Rules A solder mask bridge is the narrow strip of coating left between two adjacent openings in the mask, and it is one of the smallest features on a printed circuit board. It is also one of the most heavily loaded. During reflow the…

Immersion Silver or Hard Gold: Which Surface Finish Fits Surface finish is chosen twice in the life of most products: once when the board is assembled, and again every time a connector is mated. Immersion silver and hard gold sit at opposite ends of that spectrum. One is a thin,…

PCB Drill Targets: Registration, Tooling and Hole Accuracy Drilling looks straightforward until the numbers are measured. A hole is supposed to land in the centre of a pad, but between the artwork used to define the pad and the drill that finally makes the hole there are lamination, bake cycles,…

10-Layer Buried Via PCB: Cost Drivers and Quote Levels A ten layer board is expensive on its own. Add buried vias and the price can double, because buried vias require the board to be built in stages, with inner layer pairs laminated, drilled and plated before the outer layers are…

EV PCB Manufacturing Cost: Materials, Layers and Supply An electric vehicle contains more electronics than most people expect, and almost none of it runs on a comfortable 12 volt rail. Battery management, traction inverters, on board chargers and DC/DC converters all work at high voltage and high current in an…

Preventing Board Warpage Through Reflow A board that goes into a reflow oven flat and comes out bowed has not been damaged by a single event. It has been deformed by a temperature gradient, and the deformation has persisted because the material lost its stiffness while it was hot. Preventing…