PCB Workmanship Classes: From Design to Repeatable Production Electronics manufacturing has become a discipline of small details. Solder paste volumes, placement accuracy, temperature profiles and inspection limits all add up to the final result. This guide looks at PCB workmanship classes from the perspective of a PCBA factory floor, covering…

CAN Bus Transceiver Layout and Protection A CAN bus is designed to be robust, which is exactly why problems on it are usually caused by the boards attached to it rather than by the protocol. Termination, stub length, grounding and protection are all board level decisions, and a node that…

Board Level Shielding Cans: Design, Attachment and Removal A shielding can is a metal cover soldered or clipped over a circuit that radiates or is susceptible. It is effective, it is expensive, and it is frequently specified where a layout change would have been cheaper and more reliable. What the…

HDI Structure And Cost: Type I, II And III Two boards can have the same layer count and the same outline and still differ by a factor of three in price, because the cost of a high density board is driven by how the layers are connected rather than by…

Nitrogen Reflow Atmosphere in SMT: Benefits and Cost Nitrogen is the most commonly debated consumable in a reflow department. It clearly reduces oxidation, and it clearly improves wetting on some surface finishes, but it also adds a running cost that has to be justified product by product. The question is…

PCB Solderability Audit: Design and Assembly Considerations 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 explains PCB…

PCB Packaging, Storage and Shelf Life A board that is perfect when it leaves the fabricator can be unusable when it arrives at the assembly line. The change happens in storage and transport, and almost all of it is preventable with packaging and handling rules that cost very little. What…

Silver Copper Brazing: Solder Stop Techniques for Silver-Copper Brazing Silver-copper brazing alloys are used where a joint has to combine high electrical conductivity with a melting point above that of solder. The eutectic alloy of silver and copper melts at about 780 degrees Celsius, flows well on copper and on…

Copper Pour Clearance: How Close Is Too Close The gap between a copper pour and the things around it is one of those parameters that looks trivial until it causes a problem. Set it too small and the board is difficult to etch, the solder mask cannot form a reliable…

X-Ray Inspection of SMT Solder Joints Most solder joints on a modern board can be inspected optically, but the ones that matter most usually cannot. A ball grid array hides its joints under the package body, a land grid array hides them under the component, and a bottom terminated component…