Through-Hole vs Surface Mount Assembly: Choosing the Process The choice between through-hole and surface mount assembly is usually settled by the component list rather than by the board, but the consequences reach back into the layout. Where both technologies appear on one board, the order in which they are assembled…

Automotive PCB Price Guide: ECU, ADAS and Body Control An automotive control board is specified for a lifetime and an environment rather than for a function, and that is what makes its price structure different from any consumer board. A four-layer board with the same circuit can cost three times…

PCB Stack-Up Design for EMI Reduction: A Practical Guide Stack-up decisions are made early, before layout starts, and they set a ceiling on how quiet the finished board can be. A stack-up that places every signal layer next to a solid reference plane and keeps the layer-to-plane spacing small behaves…

Solder Paste Storage and Handling: A Process Guide Solder paste is a mixture of metal powder and flux that begins to change the moment it is opened, and most printing defects that are blamed on the stencil can be traced back to how the paste was stored, thawed and handled…

Halogen-Free PCB vs FR-4: What Actually Differs The two terms appear side by side on quotations and specifications so often that they are taken to be alternatives: a board is either FR-4 or halogen-free. It is a category error. One describes a family of base materials, and the other describes…

Why Impedance Drops After Solder Mask A controlled impedance board arrives from the fabricator with a test report showing the coupon measured exactly on target. Then the same structure is measured again after solder mask is applied, and the impedance reads lower than the design value. Nothing about the copper…

PCB Copper Thickness Selection: 1oz, 2oz and Heavy Copper Copper thickness is one of the few board parameters that changes both the electrical and the mechanical behaviour of a design at the same time, and it is chosen far earlier than most engineers realise. Once the laminate is ordered, the…

The 3W Rule and Crosstalk: What It Does Not Solve Few layout rules are as widely quoted and as widely misused as the 3W principle. Set the rule, run the design rule check, and the crosstalk problem is assumed to be solved. On a short, slow net that is often…

PCB Fabrication Notes: The Complete Checklist Every fabricated board carries a set of notes that the designer writes and the shop reads, and the difference between a smooth build and a week of questions is usually decided by how complete those notes are. The list below is the one that…

Camera PCB Price Guide: 4-Layer to HDI Imaging Boards A camera module is a sensor, a lens and a very dense board in a very small space, and that density is what drives the cost. The image sensor needs a fine-pitch interface, the processor needs impedance-controlled connections to memory, and…