Dry Film Problems in PCB Production and How to Solve Them Dry film is one of the least glamorous materials in a PCB shop and one of the most frequent sources of scrap. It has to laminate without trapping air, survive developing without lifting, and hold fine features through an…

Signal Integrity Problems on PCBs and How to Fix Them A board that works perfectly at low speed can fail intermittently at high speed without any component being faulty. The reason is signal integrity: the behaviour of the copper itself once the edges of a signal become fast enough to…

Ferrite Beads vs Inductors in PCB Design Ferrite beads and small inductors look similar on a schematic and behave very differently on a board. Choosing between them is a question of what the component is meant to do: an inductor stores energy and is part of a tuned or switching…

EMC Problems in PCB Design: A Diagnosis and Fix Workflow Electromagnetic compatibility problems are rarely solved by adding components at the end of a project. They are solved by identifying which of a small number of physical mechanisms is responsible, and then changing the geometry that produces it. The diagnosis…

PTFE Laminate PCB Fabrication: Design Rules for RF Boards Radio frequency boards are built on a different family of materials, and the fabrication that suits them is different too. A PTFE laminate has a dielectric constant close to that of air, an extremely low loss and a tendency to move…

Ground Noise: Loop, Common Impedance and Return Path Problems A ground conductor is treated as a reference, and in a schematic it is. On a board it is a piece of copper with resistance and inductance, and at the frequencies a digital circuit uses, the inductance is what matters. Current…

Aluminum Clad PCB Price: Thermal, Copper and Volume An aluminum clad PCB is one of the few board constructions where the substrate is chosen for a property other than electricity. The aluminum plate carries heat away from the components and adds mechanical stiffness at the same time, while a thin…

ENIG PCB Cost: Gold Thickness, Layers and Volume Electroless nickel immersion gold, known as ENIG, is the finish most engineers reach for when a board needs flat pads, long shelf life and a surface that survives multiple reflow cycles. It is also one of the more misunderstood items on a…

What Is on a Printed Circuit Board: Pads, Vias and Layers A printed circuit board is a set of copper features carried on an insulating base, organised so that a machine can place parts on it and solder them in one pass. Everything on the board belongs to one of…

Reducing RF Effects in PCB Interconnect Design Below a few hundred megahertz a board can usually be treated as a set of ideal connections. Above that, the same copper begins to behave like a transmission line with delay, loss and coupling attached, and the layout decisions that were harmless at…