Polyimide PCB Material: Heat, Flex and Reliability Polyimide is the material that made the flexible circuit practical. It withstands soldering temperatures, it can be made in very thin films, it is mechanically tough and it is dimensionally stable when it is processed correctly. Those properties are why it is still…

FPC Outline Design: Tolerances, Cutting and Panel Layout The outline of a flexible circuit is not a rectangle drawn around the circuit for convenience. It is a mechanical element that decides how the part is made, how it is handled and, in many products, how long it survives in service.…

IP Camera PCB Design: What the SoC Choice Changes An IP camera board is a compact system that combines an image sensor interface, a video processor, memory, a network interface and a power chain inside a housing that is often sealed. The device that gets most of the attention is…

PCB Solder Mask Repair: Process, Materials and Standards Every board shop produces a small number of panels with a local defect in the solder mask: a scratch, a pinhole, a small area of exposed copper. Scrapping the panel is the safe answer and the expensive one, so the industry has…

Multilayer PCB Routing Rules and Interface Guidelines Dense boards are routed on several layers because a single layer cannot carry the connections, but the extra layers introduce their own problems. Two conductors on adjacent layers are separated only by a thin dielectric, so they behave as the plates of a…

High-Speed Signal Board Design: Routing Techniques That Work Routing a fast signal is not a matter of drawing the shortest line between two pins. Every conductor has distributed inductance and capacitance, every transition between layers adds a discontinuity, and every place where two lines run parallel creates a path for…

Smart Water Meter PCB: Battery Life and Moisture Protection A smart water meter is a battery powered instrument that has to survive in a pit for a decade. It measures flow, logs it, reports it occasionally over a radio link and does all of that from a cell that cannot…

Warpage and Fine Lines in an ABF Package Substrate A package substrate is the board that sits between a semiconductor die and the motherboard, translating a dense array of die pads into a coarser array of solder balls. As dies have grown larger and their connection counts have risen, the…

BGA Reballing: Stencils, Reflow Profile and Reliability Reballing is the process of removing the solder balls from a ball grid array package and attaching a new set. It is used to repair a package whose balls were damaged, to change the ball alloy when a product moves to a lead…

PCB Fabrication Notes: What to Send With Your Gerbers Most fabrication problems begin with a file that was complete in one respect and silent in another. The Gerber data describes the artwork, but it does not describe the material, the finish, the tolerance or the way the boards should be…