Dielectric Withstanding Voltage Testing for PCB Insulation Withstanding voltage testing answers a simple question that no continuity test can: does the insulation between two conductors survive the voltage the product will actually see. The test applies a defined high voltage for a defined time and watches for breakdown or excess…

Reflow Soldering Quality: Profile, Defects and Control Reflow soldering quality is decided long before the board enters the oven. The paste volume, the placement accuracy and the thermal profile together determine whether every joint forms correctly, and no amount of inspection can repair a process that was outside its window…

RF Connector Surface Treatment: Keeping The Cavity Clean Surface treatment on a connector body is usually chosen for appearance or for grip, and both are legitimate reasons to texture a metal shell. What is not legitimate is allowing that treatment to reach the inside of the connector, because the cavity…

High Speed Routing Rules for PCB Layout The rules that govern high speed routing are widely published, and most of them are accurate. The difficulty is that they are not all equally important, and a designer who tries to satisfy every one of them produces a board that is expensive,…

Raising Efficiency in High Speed PCB Design Workflows High speed design has a reputation for being slow. Reviews take weeks, simulations consume days, and every change of a stack-up or a package forces the layout to be restarted. Some of that is inherent: signal integrity work rewards care, and a…

Conductive Anodic Filament Failure in PCB Laminate Conductive anodic filament failure is one of the few PCB defects that grows after the board has been built. Copper migrates along the interface between glass fibres and resin, slowly building a conductive path between two biased conductors. The result is a drop…

Termination Impedance: 50 Ohm Versus 1 Megohm A measurement is only as good as the load the instrument sees. Signal generators, spectrum analysers and network analysers are calibrated to drive and to sense a defined impedance, and when the load at the end of the cable does not match the…

PCB Tolerances: Where They Come From and What They Cost An engineering drawing is a contract, and the tolerances on it are the terms. A tolerance that is stated without a reason is either too tight, which costs money, or too loose, which costs yield, and both are avoidable. What…

SMT Production Material Management: Practical Controls Material management is the part of smt production that receives the least attention and causes a disproportionate share of the problems. A reel in the wrong place, a moisture sensitive package opened too early or a part consumed without recording turns into a stopped…

Digital Isolator Creepage and Clearance A digital isolator carries logic signals across a barrier that must survive thousands of volts, so the package rating is only half of the story. The creepage across the board surface, the clearance through the air, and the way the two grounds are separated all…