UV Curable Conformal Coating On PCB Assemblies A coating that cures in seconds under ultraviolet light solves the throughput problem that has always limited conformal coating. Instead of an oven cycle measured in hours, a conveyor with a lamp bank delivers a cured surface in a single pass, and the…

HDI Build-Up Order: What Each Additional Stage Costs A high-density design that needs more routing channels than the layer count allows leads naturally to blind and buried vias, and with them to high density interconnect construction. The decision is usually presented as a simple choice between one, two or three…

Dielectric Strength and Breakdown Voltage in PCB Insulation Insulation on a printed circuit board is a thin sheet of material that must hold off a voltage for the life of the product, and the numbers that describe it are frequently confused with one another. Dielectric strength is a material property,…

Peel Strength of Copper Foil and Laminate Bonding Copper that lifts from a laminate is one of the few board defects that can be traced to a single measurable property. Peel strength quantifies how much force is needed to pull a strip of copper away from the dielectric, and it…

PCB Assembly Carriers and Support Fixture Design A carrier, sometimes called a pallet or a support fixture, is the piece of tooling that holds a board while a machine works on it. It is easy to treat as the machine supplier’s problem, but the features that make a carrier work…

Crystal Oscillator Impedance And Load Capacitance A crystal oscillator is one of the few circuits on a board where the passive components and the routing are part of the active loop. The crystal is not a filter placed beside an amplifier; it is the frequency determining element inside a feedback…

Non-Layered PCB: A Guide to Single-Layer Boards A non-layered PCB carries a single copper layer on an insulating base, and its simplicity is the whole point. It is the cheapest board that can be manufactured at volume, it is fast to build, and for a large class of products it…

Insertion Loss In High Speed PCB Traces A long high speed link does not fail because the driver is too weak or the receiver too insensitive. It fails because the channel has quietly removed the high frequency content that the receiver needed to resolve a one from a zero, and…

Rework and Repair Guidelines for Assembled PCB Boards Every assembly line produces boards that need a second look, and how those boards are handled separates a controlled process from an improvised one. Rework restores a product to specification; repair restores function where the original structure has been damaged. Both are…

Driver PCB Cost: What a Driver Board Really Costs A driver board sits between a control signal and a power stage, and its cost is set by the power it handles rather than by the logic it contains. Current, switching frequency and isolation distance each push the specification in a…