Resin Plugging vs Via Tenting: Choosing the Right Via Treatment A via can be left open, covered with solder mask, filled with mask ink or filled with resin and capped. The choice looks like a detail on the fabrication drawing, but it decides whether solder balls form during assembly, whether…

ACF vs FPC: Anisotropic Conductive Film in Flex Assembly An anisotropic conductive film is a bonding material, not a circuit board. It is a thin adhesive loaded with conductive particles that conducts in one direction only, so a row of fine pitch pads on a flex circuit can be joined…

LED Aluminum Substrate Thermal Conductivity Explained An LED aluminium substrate is judged on three numbers: thermal conductivity, thermal resistance and dielectric strength. The aluminium plate is not the limiting factor, because aluminium conducts heat well. The thin insulating layer between the copper circuit and the metal base decides almost everything,…

Ferrite Bead Selection for EMI Suppression on PCBs A ferrite bead looks like an inductor and is often drawn like one on a schematic, but it behaves differently. It is specified in ohms rather than henries because the important figure is the impedance it presents at a given frequency, not…

Ceramic PCB Guide: Materials, Processes and Design Rules A ceramic PCB is chosen when the board has to do something an organic laminate cannot: hold a bare die at a controlled temperature, stand off a high voltage at high temperature, or survive a thermal cycle that would fatigue an FR4…

Direct Plated Copper: A Complete Technical Guide Direct plated copper is a process that creates the conductive layer inside a hole without the graphite or the palladium catalyst that a conventional electroless copper line requires. Instead, a conductive polymer is deposited on the dielectric surface and then copper is electroplated…

LED Lighting PCB Basics: Substrate, Thermal Design and Layout An LED luminaire lives or dies by its thermal path, and the printed circuit board is the first link in that path. Unlike a logic board, an LED board feeds a continuous current into devices that turn much of it into…

PCB Prototype Types: Materials and Construction Choices A PCB prototype is not simply a small quantity of a production board. It is a board built to answer a question, and the construction that answers the question most cheaply is often not the construction that will be used in production. Choosing…

PCB Etching: Process Control, Tolerance and Cost Factors PCB etching removes the copper that the resist does not protect, and it is the step that determines whether the trace widths on the finished board match the widths in the design. Because the process removes copper in every direction, a nominal…

Alumina PCB: Material Properties and Design Guide Alumina is the material that electronics uses when the operating temperature is too high for any polymer laminate. A board built on aluminium oxide ceramic does not soften, does not outgas and does not burn, and its thermal conductivity is many times that…