These are some of the challenges facing designers as they route complex printed circuit boards. They are well suited for via-in-pad applications and high-density interconnect (HDI) designs that require smaller traces and vias. Microvias are created with a laser, which allows them to be much smaller than a mechanically drilled hole, and they typically span only two layers of the board. These vias require more fabrication steps to create, as the individual layer pairs of the board have to be drilled and aligned prior to laminating the board together. A blind or buried via is also drilled mechanically, but it will either only go partially through the board or start and stop on internal layers. They are mechanically drilled and go all the way through the board. Thru-hole vias are the standard via used in the design of a circuit board. Designers will use an array of different via types and sizes for their routing. In today’s PCB design CAD systems, however, a more precise method is needed. When circuit boards used to be laid out manually with tape and dollies, a designer could simply take an Exacto knife and trim down a via pad to squeeze a trace by it. Some of these are as follows:Ĭonnectors may require nets to use a smaller trace width to snake their way between closely spaced pins.įine-pitch parts such as quad flat packages (QFP) or small-outline packages (SOP) may need their trace widths reduced for escape routing.īall grid arrays (BGA) may also require shrunken trace widths to route in and around the pins and vias of the package.Īnother part of PCB routing is the vias used for transitioning between layers.
In addition to these trace width and spacing requirements based on the functionality of the circuit, there also may be different width and spacing requirements dictated by their location. Power supplies which could have multiple trace widths depending on the circuit.Įxtra spacing between analog and digital routing to keep them isolated from each other. Power and ground connections which will need a wider trace. Sensitive high-speed traces that need to be isolated from other routing with wider spacing.Īnalog routing which may have a different default width spacing requirement. Now, on any given board you may see some or all of the following:Ĭontrolled impedance routing with specified widths and spacings. As circuit board technology grew, however, the trace width and spacing requirements became much more complicated. Any other trace widths that might be required would be few and could be easily handled by manually changing them during routing.
![pcb trace width calculator pcb trace width calculator](https://www.ourpcb.com/wp-content/uploads/2018/01/PCB-trace-calculator1.png)
Your traces were all assigned to a default width and spacing, except for where power and ground connections connected to their vias, which had to be made wider. The Challenges Posed by Today’s PCB Routing TechnologiesĪt one time, routing traces on a printed circuit board was a fairly straight-forward procedure. Here are some of the challenges facing designers today as they route their circuit boards, as well as some methods you can use to successfully route according to the required rules and constraints.
![pcb trace width calculator pcb trace width calculator](https://manage.pcbgogo.com/img/js/ueditor/ueditor1.4.3.3/net/upload/image/20190718/6369906905018400005042160.png)
In addition to specific areas that nets can be routed in or layers that they can be routed on, there are also different PCB trace width and spacing rules that have to be managed as well. In today’s PCB layouts, each net may have different and unique routing characteristics that have to be applied to it in order for it to function as designed. Routing traces on a circuit board can be a very rewarding accomplishment, but it also can get very complicated as the designs grow in size and complexity. Long before Tetris or Candy Crush, trace routing gave designers their own unique puzzles to solve by untangling a rat’s nest of net connections in order to create a cleanly routed board. One of the advantages of being a PCB designer is getting to route traces in a printed circuit board layout. Using your PCB design CAD tools to help you.Ī multi-layer circuit board showing the routing on the internal layers. The challenges of routing that designers are facing.Įxamples of trace width and spacing requirements.