How to Judge PCB Quality Before Assembly A finished board can look perfect and still fail in assembly. The defects that matter are usually not visible at the surface: a thin plating, an oxidized pad, a laminate that absorbs moisture, or a joint that holds until the first thermal cycle.…

Immersion Tin Surface Finish: Chemistry and Process Control As lead-free soldering spread through the industry, and as high reliability products such as automotive electronics became the dominant users, immersion tin moved from a niche finish to a routine one. Its appeal is straightforward: a thin, flat, solderable layer that suits…

High-Speed Backplane Design: Link Budget, PINMAP and Materials A high-speed backplane is the board every other board plugs into. That single fact changes the design problem completely. A normal printed circuit has a defined function and a defined set of interfaces, but a backplane has to connect an entire system,…

Stepped PCB Manufacturing: Cavity, Controlled Depth and Lamination A stepped board, also called a cavity board, is a multilayer construction in which part of the outer surface is machined away so that an inner layer becomes the top surface in a defined area. The purpose is mechanical: a tall component…

Copper Core Substrate: Fabrication and Surface Finish Choice A copper core substrate is a middle ground between a conventional laminate and a ceramic. A metal plate carries the heat, a thin dielectric insulates it from the circuit, and the copper foil on top is processed like any other printed circuit.…

Castellation PCB Modules: Design and Assembly Guide A castellated module is a small board with plated half holes along its edge, so that it can be soldered onto a carrier board like a surface mount component. It is the standard way to package a radio, a power converter or a…

Drone Flight Controller PCB: IMU, Power and Vibration A flight controller takes data from gyroscopes, accelerometers, a barometer and a satellite receiver, performs sensor fusion into an attitude estimate and drives four or more motor controllers in a loop that runs hundreds of times a second. Every one of those…

Edge Computing Gateway PCB: Thermal, High Speed and Power An edge computing gateway sits between the sensors in a factory and the network that collects their data. It has to run a processor fast enough to filter and buffer a stream of information, it has to do so inside a…

In-Circuit Test on PCBs: Fixtures, Test Points and Coverage In-circuit test checks the components on an assembled board one at a time: it measures a resistor, verifies the polarity of a diode, confirms that a capacitor is present and that its value is within tolerance, and detects a short or…

Throwing Power and Plating Uniformity in Deep PCB Holes Plating a hole uniformly is harder than plating a flat surface, and the difficulty grows with the depth of the hole relative to its diameter. The reason is that the plating solution has to be exchanged inside the hole while the…