The core of PCB design: physical layout

Studies have shown that a majority of design time is spent on placement and routing. That said, over the past 20+ years, much has changed when it comes to the overall design process. Electrical engineers are now often responsible for the complete PCB design, from logic design to physical layout, and high-speed designs are now commonplace, resulting in complex constraints that need to be defined, captured, and managed. And let’s not forget time-to-market pressures. Each phase of the design cycle, including placement and routing, needs to be done quickly, and correctly, the first time, making automation within your design tools essential.

Placement

The schematic is typically organized with components that interconnect close to one another, usually on the same schematic page. PADS Professional Premium will organize parts into groups, so when you are in the layout environment, you can place each group easily, and keep these components together, rather than having to search for them.

Constraints

Constraints can be a tedious, time-consuming process to capture and enter. The PADS Professional Premium Constraint Editor has an easy-to-use spreadsheet user interface – a look and feel we’re all familiar with. Once entered, these constraints are automatically adhered to, whether it’s a mechanical constraint such as trace width and clearances, or electrical constraints such as time-in-flight and delay.  These will be maintained during interactive routing and can be verified before generating manufacturing outputs. There is also the ability to detect differential pairs in the schematic, and automatically create them in layout.

Routing

Routing the design is no longer just “connect the dots.”  All the constraints need to be maintained.  Once entered, the interactive routing will ensure these rules are met.  During interactive routing, graphics tools will be displayed showing trace lengths as you add them if you have length constrained traces (minimum/maximum or matched length traces).  The Sketch Router allows you to select multiple traces at once, and then “sketch” a path you’d like to have them follow.  The system will then find the best paths, following your rough sketch as best as it can.  Sketch Router will accelerate this portion of the design process, helping you meet your time to completion goals.

Commands

Accessibility to commands helps speed up the design process. While designing in PADS Professional Premium, most available commands are displayed on a menu by simply clicking the right mouse button.  There is also a function toolbar that can be displayed at any time.

Physical layout with PADS Professional Premium

PADS Professional Premium has much more to offer in terms of physical layout functionality, including:  correct-by-construction design, self-healing planes, a concurrent 2D and 3D environment, and support for advanced fabrication design including HDI, RF, rigid-flex, and embedded components.  It has the functionality to tackle any of your design challenges and allow you to meet you time to completion goals.

To learn more about physical layout download our eBook!

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This article first appeared on the Siemens Digital Industries Software blog at https://blogs.sw.siemens.com/electronic-systems-design/2022/11/23/pcb-design-physical-layout/