Multilayer PCB Design Tolerances Explained Every dimension on a fabrication drawing carries a tolerance, and every tolerance costs money to hold. The skill in a multilayer design is not to demand the tightest value everywhere, but to identify the few dimensions where accuracy actually matters and to leave the rest…

Board Size and Cutting Dimensions for PCB Prototypes The outline of a board looks like the simplest part of a design, and it is usually the last thing anyone checks. In practice board size is constrained by the panel the fabricator runs, and the way the boards are separated from…

Does a Higher PCB Layer Count Mean Better Performance? More layers is a common shorthand for a better board, and it is wrong often enough to be worth examining. Layer count is a design decision that follows from routing density, reference requirements and the number of supply voltages. Beyond the…

Component Usage in Prototyping: Latch-Up, Filters and Spare Inputs Most product failures traced to component choice are not caused by the wrong part number. They are caused by a part that was used correctly on paper and left in a condition the circuit could not tolerate: an input floating, an…

Clean Production Measures in FPC Manufacturing Clean production in circuit board manufacturing means reducing pollution at the source rather than treating it at the outlet: improving the process, choosing less hazardous chemistry, using equipment that contains what it produces, and recovering what would otherwise be discharged. For flexible circuits, whose…

Fine Line Production in PCB Fabrication: Resist, Exposure and Etching Component packages have moved toward ball grid arrays and finer pitches, and the consequence for the board is a steady reduction in conductor width and spacing combined with an increase in layer count. Width and spacing save area; layers save…

Characteristic Impedance Control in PCB Design: Width, Height, Dk Impedance is the property that separates a board that merely conducts from a board that transmits. A design that passes continuity and isolation testing can still fail to carry a fast signal, because what is being conveyed along the trace is…

32.768 kHz Crystal Layout: Load Capacitance and RTC Accuracy A real-time clock keeps time while the rest of the product is powered down, and it does so with a crystal that operates continuously from a small backup supply. That crystal runs at a low frequency and draws very little current,…

PCB Lamination Press Cycle: Key Process and Quality Checks Modern electronics depend on boards that are assembled correctly the first time. Every product – a phone, a charger, a medical instrument or an industrial controller – relies on thousands of solder joints that must conduct current for years. This article…

Electroless Copper in PCB Holes: Process Steps and Control Every plated through hole in a printed circuit board starts life as an insulating wall. The resin left by the drill does not conduct, and electroplating cannot begin on a surface with nowhere for the current to flow. Electroless copper is…