Motor Control PCB Cost Drivers and Design Choices Motor control boards sit at the intersection of power electronics and embedded design, and their cost is driven by decisions taken long before a supplier is approached. Bus voltage, current level, isolation and thermal path each set a floor under the price,…

Fabrication Data Package Checklist before Production A fabrication data package is the complete description of the bare board: geometry, materials, tolerances, finishes and the tests that will verify them. When it is complete, the fabricator builds what the designer intended. When a document is missing or contradictory, the plant makes…

Leaded versus Lead Free Process Selection for Assembly Assembly processes split into two families: tin lead alloys and lead free alloys. The choice affects the oven profile, the surface finish, the rework procedure and the reliability assumptions, and it cannot be changed at the last minute because several decisions depend…

Layout Handoff Documentation for PCB Design Services Handing a design to an external layout team is one of the points where projects lose time, and the loss is usually caused by missing information rather than by technical difficulty. Good layout handoff documentation answers the questions the layout engineer would otherwise…

Ceramic Substrate PCB Advantages for Thermal and RF Designs Ceramic substrates appear in designs where the thermal load, the operating frequency or the environment rules out ordinary laminate. They cost more per square centimeter and they cannot be processed like a conventional board, but they solve problems that no amount…

Gage R and R Studies for PCB Measurement System Analysis Before a process can be controlled, it has to be measured, and the measurement itself has to be trustworthy. A thickness gauge, a microscope scale or a tester that reads inconsistently will produce data that looks like process variation. A…

Connector Footprint Design Guide A connector footprint is the set of pads, holes and keep out areas that a connector needs. It is copied from a datasheet, drawn from a drawing or taken from a library, and the differences between those three sources cause more assembly problems than any other…

Mixed Alloy Reflow Profile For Backward Compatibility Not every assembly uses one solder alloy. A board may carry a lead free ball grid array and be soldered with a tin lead paste, or it may carry a leaded component on a lead free board, or it may be assembled with…

Solder Mask Thickness: Preparation, Placement and Process Control Solder mask thickness is a number that rarely appears on a drawing and that decides several things at once. The film has to insulate the copper, survive the soldering process, hold its shape between fine pads and adhere to the laminate. A…

Through Hole Solder Barrel Fill And Wicking A through hole joint is judged by two things that are visible and one that is not. The visible ones are the fillet on the solder side and the fillet on the component side; the invisible one is how much of the barrel…