In this ongoing series on PCB layout from the design team at PNC, previous posts have looked at some of the initial steps to turn a circuit schematic into a manufacturable, reliable PCB. These posts have looked at component placement [1], selecting appropriate trace widths [2], and BGA routing [3]. In this post we are going to take a deeper dive into methods for reducing crosstalk in the PCB design [4]. After the power and ground have been routed, the next task is to route high speed signal traces, and the traces that could either generate or receive crosstalk. What is ...
First article inspection (FAI) prior to SMT assembly [1] is a design verification methodology that provides a reported verification and validation of details of a product on the shopfloor per its manufacturing procedure and requirements. There are various ways to perform FAI, from both supplier’s and customer’s side, making it a very dynamic process. This means that each organization can tailor its FAI method to benefit itself and consequently, its customer, yet maintain rigid performance standards at the same time. FAI involves qualitative and quantitative measurement. FAI is also highly effective since it can potentially fulfill process validation requirements of ...
What is Conformal Coating? Conformal coating is protective chemical material coating applied after the final SMT PCB assembly [1] or through-hole assembly process. Coatings are comprised of 5 different types, Acrylic, Epoxy, Urethane, Silicone and Parylene resins. Applying the coatings to a PCB board assembly [2]can be done by hand spray, robotic spray, brush or dipping. The coating acts as an additional dielectric layer that provides protection due to environmental and mechanical stresses, such as thermal extremes, chemicals, dust, salt fog, abrasions, and moisture. In a PCB assembly [3] that has close spacing of conductive pathways or close ...
New product designs continue to get more compact, while the performance and the number of features that customers expect continue to increase. To the engineer, this means higher PCB circuit densities and less room on the PCB for just-in-case design, such as unallocated I/O, or 0 ohm resistor networks to allow for reconfiguration of the PCBs at PCB assembly [1]. Meanwhile, new product prototype cycles are also getting faster. 3D printed mechanical parts are available within hours, putting pressure on electrical engineers to work faster and get their PCB designs [2] right the first time. Even the fastest PCB fabrication, such ...
How Do You Select a Printed Circuit Board Thickness? Selecting the correct PC Board [1] thickness for your product requires balancing of three often competing aspects of the design: manufacturability, electrical performance and mechanical constraints. Modern PCB fabrication techniques at PNC give the PCB designer great flexibility in specifying the PCB lamination stack-up and gives them the option to design a PCB in a thickness other than the typical choices of .031”, 062” or .093”. Manufacturing considerations in selecting a PCB thickness To understand how to specify PCB thickness, it is important to understand how PCBs are fabricated. Most multilayer PCBS from 2 ...