HDI 1+N+1 vs 2+N+2: Microvia Stackup Comparison The shorthand that describes a high density board, such as 1+N+1 or 2+N+2, encodes how many microvia layers have been added to each side of an ordinary core. The first number is the count of build-up layers on top, N is the conventional…

VR Headset PCB: Choosing Rigid, Flex and HDI Boards A VR headset is a wearable computer with a display attached to the user’s face, and that combination sets the PCB requirements: high speed links between tracking sensors and processor, tight thermal limits because the electronics sit against the skin, and…

PCB Manufacturing Tolerances: What a Fabricator Can Hold Every feature on a printed circuit board is produced by a process that has a natural spread, and the tolerance on the drawing is a statement about how much of that spread the design can absorb. Manufacturing tolerances are therefore not a…

Measurement Equipment PCB: References, Guarding and Noise A measurement instrument is judged by numbers, and the board is what makes those numbers mean something. A digital multimeter, a bench power supply or a data logger all rest on a reference and on an analogue front end whose errors have to…

Metal Core PCB: Aluminium Substrates and Thermal Design When a component has to lose several watts through the board beneath it, a glass reinforced epoxy substrate becomes the bottleneck. A metal core board replaces the structural laminate with aluminium or another metal and separates it from the copper circuit by…

Immersion Tin PCB: Flat Finish Cost and Selection Guide Surface finish is one of those decisions that looks minor on a drawing and becomes a production problem six months later. Immersion tin sits between HASL and ENIG in both price and performance, offering a very flat pad for fine-pitch assembly…

Heater PCB Price Guide: FR-4, Aluminum, Ceramic A heater board is a power product with a sensor attached, and that combination drives its cost more than any layout decision. The same circuit that would be trivial on a logic board has to carry several amps, survive a hot enclosure and…

Implantable Medical Device PCB: Manufacturing and Design Guide An implantable device is the most demanding application for a printed circuit board, because it cannot be repaired, it cannot be replaced without surgery, and it operates in an environment that is warm, wet and chemically aggressive. An implantable medical device PCB…

Practical Notes on CVD Driver Board Chemical vapour deposition is a process in which a solid material is formed on a substrate from a gas phase reaction inside a vacuum chamber. The equipment that performs it is a collection of demanding subsystems: a vacuum pump, a pressure control valve, a…

Ordering a PCB Prototype: Checks Before You Send A prototype order is a small transaction with an outsized influence on the project. The files that are sent, the questions that are asked and the checks that are performed before the panel is built decide whether the first boards arrive usable…