Accelerometer Mounting and PCB Design A MEMS accelerometer reports the motion of the package it is soldered into, which means it measures the board as much as the machine. Everything the board does under vibration, from flexing in the middle to ringing at a mounting screw, appears in the output…

Thermally Separated Metal Core PCBs for Power Electronics An aluminium backed board is an efficient way to remove heat from a power component, but it has a weakness. The dielectric layer that insulates the circuit from the metal base is thin and is a much poorer conductor than the aluminium,…

Skills For High Speed Design: Seven Areas That Matter High speed design is often described as a set of rules to memorise, which makes it sound harder than it is. The rules exist because the interconnect behaves as a transmission line, and once that idea is understood the rules become…

Conductive Anodic Filament: Design Rules and Process Limits A board that passes every inspection and every electrical test can still fail in the field from a mechanism that grows after it is installed. Conductive anodic filament is the name for that mechanism, and it is worth understanding because its symptoms…

Fiber Weave Effect: Why Differential Pairs Drift A differential pair is supposed to be two traces that see identical conditions, so that any disturbance affects both of them equally and cancels at the receiver. On a real board that assumption is not quite true, because the laminate underneath is not…

Hall Effect Sensor Interface Design A Hall effect sensor converts a magnetic field into an electrical signal without contact, which makes it the natural choice for position, speed and current measurement in equipment that has to run for years. The device itself is simple, but the interface around it decides…

Solder Mask Bridges and the LDI Process A solder mask bridge is the narrow strip of mask that remains between two adjacent pads after imaging and development. Its purpose is to stop solder from bridging the pads during reflow, which makes it a functional feature rather than a cosmetic one.…

Common PCB Design Mistakes and How to Avoid Them Most board problems that reach production are not exotic. They are the same short list of mistakes, repeated across companies and across products, and almost all of them are avoidable with a review process that looks for them deliberately. A layout…

Moisture Sensitivity Level: Design Rules and Process Limits A reel of components that has been open on the shop floor for a week is not the same material it was when the seal was broken. The plastic package has absorbed moisture from the air, and when the assembly enters reflow…

Placement Machine Accuracy: What the Specifications Mean A placement machine is usually selected on the basis of a specification sheet, and the specification sheet is usually written in a way that makes comparison difficult. Accuracy, repeatability, resolution and speed are quoted in different units by different manufacturers, at different confidence…