Free Trials

Download a free trial to find out which Altium software best suits your needs

How to Buy

Contact your local sales office to get started on improving your design environment


Download the latest in PCB design and EDA software

  • Altium Designer

    Complete Environment for Schematic + Layout

  • CircuitStudio

    Entry Level, Professional PCB Design Tool

  • CircuitMaker

    Community Based PCB Design Tool


    Agile PCB Design For Teams

  • Altium 365

    Connecting PCB Design to the Manufacturing Floor

  • Altium Concord Pro

    Complete Solution for Library Management

  • Octopart

    Extensive, Easy-to-Use Component Database

  • PDN Analyzer

    Natural and Effortless Power Distribution Network Analysis

  • See All Extensions

    World-Renowned Technology for Embedded Systems Development

  • Live Courses

    Learn best practices with instructional training available worldwide

  • On-Demand Courses

    Gain comprehensive knowledge without leaving your home or office

  • Altium 365 Viewer

    View & Share electronic designs in your browser

  • Altium Designer 20

    The most powerful, modern and easy-to-use PCB design tool for professional use


    Annual PCB Design Summit

    • Forum

      Where Altium users and enthusiasts can interact with each other

    • Blog

      Our blog about things that interest us and hopefully you too

    • Ideas

      Submit ideas and vote for new features you want in Altium tools

    • Bug Crunch

      Help make the software better by submitting bugs and voting on what's important

    • Wall

      A stream of events on AltiumLive you follow by participating in or subscribing to

    • Beta Program

      Information about participating in our Beta program and getting early access to Altium tools

    All Resources

    Explore the latest content from blog posts to social media and technical white papers gathered together for your convenience


    Take a look at what download options are available to best suit your needs

    How to Buy

    Contact your local sales office to get started improving your design environment

    • Documentation

      The documentation area is where you can find extensive, versioned information about our software online, for free.

    • Training & Events

      View the schedule and register for training events all around the world and online

    • Design Content

      Browse our vast library of free design content including components, templates and reference designs

    • Webinars

      Attend a live webinar online or get instant access to our on demand series of webinars

    • Support

      Get your questions answered with our variety of direct support and self-service options

    • Technical Papers

      Stay up to date with the latest technology and industry trends with our complete collection of technical white papers.

    • Video Library

      Quick and to-the-point video tutorials to get you started with Altium Designer

    Stay Grounded: Digital, Analog, and Earth Ground in PCB Layout

    Altium Designer
    |  September 25, 2018

    Retro technology circuitry and grounding

    In electronics, I get equally confused by the different types of grounds involved in PCB design: digital, analog, and earth ground. It’s hard not to be perplexed when university lecturers have always pointed out that although the grounds share the same reference, they are represented by different symbols.

    Theoretically, it’s easy to understand that digital electronics components are referenced to the digital ground and the same applies to analog circuits. They are clearly differentiated by the ground symbols used in schematics. However, the real challenge is physically routing and placing the respective grounds on the PCB.

    What Does the Ground Actually Do?

    Digital currents, whether single-point ground current flow or proper grounding and grounding scheme with reference points, ground pins and ground testers for measurement for digital circuits. Whether you’re trying to incorporate components like an anti-aliasing filter or differential amplifier, or an analog-to-digital convertor, or being wary of signal and noise distinctions in your device or power supply with signal-to-noise ratio and voltage drop, you’ll need to know what you’re looking for.  

    Sometimes, you need to get back to the basics to master the art of grounding in PCB design. This means going beyond the schematic symbols of the ground. In a typical electronics system, a ground provides a reference to the signals, both digital and analog. Therefore, to achieve a reliable signal, the ground needs to be relatively ‘clean’.

    The ground also functions as the return path to the electric current that flows through the signal traces. With respect to the current path, there are two things that you need to keep in mind:

    1. Electric current always travels through the path of least resistance.
    2. The size of the ground trace must be sufficient to handle any high current.

    Digital, Analog, and Earth Ground

    Digital circuitry is often characterized by the quick transition of signals swinging between the Vcc and 0V. Naturally, the ground would be subjected to spikes, as electric current pulses through. On the other hand, analog signals heavily depend on a stable ground to provide an accurate reading.

    The earth ground actually refers to the physical connection that extends to the earth itself. It is usually connected to the chassis or used to safely channel electrostatic discharge from adjacent components. Theoretically, the earth ground is a neutral electrical plane; reality, however, proves that it can sometimes be rather noisy.

    Connecting Different Grounds on the PCB

    Getting the ground patterns correct on the PCB can be a tricky subject, even for seasoned engineers. For instance, a single mistake in audio and digital grounding can lead to static noise coupling to the audio output. It’s for new designers to use a single ground plane, resulting in the analog inputs fluctuating randomly.

    Some electronics experts point out that a star connection is one of the best methods to connect the various types of grounds at a single point. However, in some situations, the star connection may not be practical, due to the component arrangement on the PCB or space constraints.

    After making many mistakes with ground connections, I finally learned how to design stable grounds. I prefer using the ground bar method and segregating the power, digital and analog modules on the PCB. Below is a general diagram of what this grounding system would look like.

    Power, digital, and analog ground

    Sample layout of grounding

    Of course, this method of grounding is only applicable when components can be clearly separated according to their functions. The principle in arranging the ground planes is placing the noisiest ground at one end and the most sensitive ground on the other end.

    In some cases, the ground plane only needs to be separated at a specific component. This can be done by separating the ground planes beneath the component in the following manner:

    Separate ground planes beneath component

    Ground planes underneath a component

    Ground placement in a PCB should not be treated as an exclusive subject. Instead, designers should apply sense, or rather the basic laws of electronics and a vivid imagination to visualize how electrons travel along the path formed by different ground arrangements.

    Once you’ve determined your grounding strategies, the actual implementation is pretty easy with intuitive polygon tools in Altium Designer®​ . If you’re unsure about your ground placement or need a refresher on key grounding topics, talk to an expert at Altium.

    About Author

    About Author

    PCB Design Tools for Electronics Design and DFM. Information for EDA Leaders.

    most recent articles

    Back to Home