Flame Retardant Absorber Material Selection A material that carries a flame rating is not automatically the right material for an electromagnetic problem. The rating answers a safety question, and the absorption answers a functional one. In products such as a base station antenna housing, a battery enclosure or a data…

Express Prototype Service: What Changes When the Lead Time Drops Express service compresses the fabrication into a few days by sharing panels, running small batches and limiting the process steps. It is genuinely useful and it changes what is being built in ways that are worth understanding. How the Time…

IPEX3 Connector Selection For Compact RF Boards When a wireless module has to fit into a product smaller than the palm of a hand, the board level antenna interface becomes one of the largest components on the board. A threaded connector is mechanically excellent and far too bulky, so the…

FR4 Versus Rogers Versus Aluminium Substrates Most boards are built on FR4 because it is cheap, well understood and available in every shop. As soon as the frequency rises or the power density increases, that choice becomes a compromise, and two alternatives appear: a low loss laminate such as Rogers,…

Four Layer Metal Core Board Stack Options A metal core board is chosen for one reason: heat has to leave the components through the back of the board. The simplest version of the structure carries a single copper layer on a thin dielectric over an aluminium plate, and for many…

LVDS Clock Buffer Layout And Termination Practice A clock buffer that distributes one reference to four or more loads is judged by two numbers that a schematic cannot show: how much jitter it adds, and how far apart the outputs drift from each other. Both are decided largely by the…

Thermal Interface Material Thickness and Contact Resistance The thermal path from a hot component to a heatsink or chassis is only as good as the interface between them. Two flat surfaces that look smooth in the hand touch at a small number of high points, and the air trapped in…

Common Mode Choke Selection for Signal and Power Lines A common mode choke presents a high impedance to the current that flows in the same direction on both conductors and a low impedance to the signal. Its selection is usually made on the impedance figure alone, which is the least…

Procurement Documentation: Specifications, Drawings and Supplier Dialogue Most disagreements between a customer and a fabricator come from a document that is incomplete rather than from a process that is incapable. The specification is the interface, and it is worth more attention than it usually receives. What the Fabrication Drawing Must…

EV Charging PCB Design: Copper, Voltage and Heat A charging station is a power converter with a network connection, and its board has to carry mains current, switch it at high frequency and remain safe when something fails. That combination puts requirements on the copper, the spacing and the material…