Whether you're building a house or a PCB, you need to have the right tools in your toolbox. Every designer needs to use CAD tools for component placement, but even command line-based CAD software can be used to precisely place components. As modern electronic devices become more complex at all levels, designers need tools that can help speed up basic design tasks.
Choosing the right PCB design tool requires weighing many potential options. There are many packages on the market with different features, and no one has the time to deal with free trials for each package. Some of these design platforms still use the same outdated workflows that were used 20 years ago. With that in mind, let's take a look at some of the basic tools every designer needs in their PCB design software.
Schematic design and capture
Your electronic schematics are like the foundation of the house. Everything you place on the board is based on this underlying document. This important document shows the components required for the board, how they are connected, and where the power and ground connections are. With the right schematic editor, you can easily plan the layout and annotate your board.
Using a schematic editor can keep your board organized, but once your design becomes more complex, using a single schematic can become unwieldy. Once you start including multiple functions on the board, you can stay organized by using layered schematics. This allows you to separate components into different schematics based on how they match functional blocks, and you can define parent-child relationships between schematics.
Using a multi-channel PCB design tool will not only help you stay organized, but also make it easy to copy the groups of components in the layered schematic. Once you capture your schematic as the initial layout, these duplicate groups of parts are transferred to the new board. You can then start wiring between components, as well as placing power and ground connections.
Routing function
Once the schematic is captured as an initial layout, your CAD tool will be on standby to help you place components and route traces. Routing is a critical task in defining the physical connections between components on the board. With simple design, it's a no-brainer to manually lay out each connection and check the layout against your design rules. But as your boards become more complex and the number of interconnections required increases, tools that can automate the routing process can save you a lot of time.
The debate between the merits of automatic and interactive routers seems eternal. For simple boards that do not involve differential pairs, a large number of signal networks, or a limit on the number of holes on the interconnect, the automatic routing device can still produce a suitable layout. Note that in these cases, if you can define an appropriate routing policy, your auto routing machine will produce a better layout.
This is where automatic interactive routing becomes an important PCB design tool. An automatic interactive cabling blends the best aspects of automatic cabling and interactive cabling. You can manually define waypoints on interconnects for a given signal network, and the tool will automatically route traces in the network between source components, those waypoints, and your load components.
Signal integrity and power transmission analysis
When it comes to signal integrity, the switching speed of modern digital ics is fast enough that ensuring the signal stays clean becomes an important consideration for almost all designers. Ensuring signal integrity really requires designing the right layer stack, trace geometry, and ground plane for your specific application. All of these are tasks for CAD, routing and board design tools.
If you use the right signal integrity package, you can check for reflection and crosstalk waveforms in different networks. This helps you determine when you need to terminate and which matching network should be used in different traces.
In terms of power transmission and thermal management, the Power Transmission network Analyzer (PDNA) can be used to determine IR losses throughout the track, power supply and ground layer, and through holes. Your PDNA should produce voltage and current density results using an intuitive output format. The best tools will show you an interactive color map that allows you to visually check your board for potential power heat issues and excessive IR voltage drops.
PCB design tool for rule-driven engine
Perhaps the most important part of PCB design is ensuring that your design complies with basic design rules. When creating a layout, your design function should check the design data against these rules so that you can quickly identify problems and correct them as needed. Your design rules can also limit the capabilities of CAD and routing functions, helping you comply with important criteria for your design.
Other PCB design packages divide these important functions into different programs, forcing you to export and re-import data as you move between programs. When a new version is released, you will have to devise a complex workaround, and there is a real risk that your old data will suddenly become inaccessible. The workflows and interfaces in this environment are not consistent in the design tools, which exacerbates the learning curve and reduces design efficiency.
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