ESD Damage Investigation and Control Verification Electrostatic damage is difficult to prove because the damage is often invisible and the event leaves no record. A device that fails after handling may have been damaged weeks earlier, or it may have been damaged by the test fixture that is now measuring…
High Layer Count PCB Fabrication Challenges and Controls Boards with ten, twenty or more layers are built on the same principles as a four layer board, but every tolerance that was comfortable at four layers becomes tight. A high layer count pcb concentrates the difficulty in registration, lamination and drilling.…
PCB Footprint Library Naming and Management Practice Searching a component library by part number looks obvious until the first thousand pad layouts are filed under package names instead. A workable footprint library is organised by the physical package, and that decision shapes how it is named, reviewed and maintained. Footprints…
Microcontroller Clock System Design and Clock Source Selection Every microcontroller peripheral is timed from the same tree, so the microcontroller clock system design decides start up time, accuracy, power consumption and electromagnetic behaviour at once. The choice of clock source is therefore a system decision rather than a component decision.…
Resolver Interface Circuit Design A resolver is a rotating transformer whose two secondary windings report the shaft angle as a pair of amplitude modulated signals. It survives heat, vibration and radiation that would destroy an optical encoder, and in exchange the electronics has to excite it and then recover an…
Digital Clock PCB Design From Schematic to Enclosure A clock is one of the classic microcontroller projects, and it is a good example of how much of a digital clock pcb is decided by the display and the enclosure rather than by the firmware. The board has to be readable…
Odd Form: Design for Automated and Manual Odd-Form Assembly Odd-form components are the parts that the placement machine cannot handle at the standard rate: connectors, transformers, large capacitors, modules and anything that arrives in a tube or a tray. They are also where most of the manual work on a…
PCB Assembly Cost Drivers and Quotation Inputs An assembly price is the sum of a material cost, a process cost, a test cost and a yield allowance. The quotation is usually argued at the total, when the decisions that set it were made in the design. What Drives the Material…
Planar Coil PCB Design for Inductive Sensing and Power Some boards exist to carry components, and some exist to be the component. A planar coil replaces a wound inductor with copper windings etched into the layers, and the reason to do that is repeatability as much as size. What a…
Gate Driver: Design Rules and Process Limits A gate driver sits between a controller that runs at a few volts and a power switch that may sit hundreds of volts above or below it. The isolation between the two is the defining feature of the part, and the way it…
