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When to use a star ground for grounding?
In star grounding, all analog and digital ground connections should terminate at your star ground. The topology in star grounding is simple: connect the different digital and analog ground planes or traces back to a single point (the power supply return). The idea here is to physically isolate different ground regions.
Why do I need a star ground on my PCB?
When you have analog and digital components on a PCB, you’ll have issues like EMI when the grounding is not executed properly. A star ground provides a clear separation between the different grounds and prevents noise induced from one module coupling to another. I’ve made the mistake of leaving out the star ground in one of my audio projects.
How does the star ground philosophy work in a circuit?
The key to handling grounding is to understand how the currents flow. The “star” ground philosophy builds on the theory that all voltages in a circuit are referred to a single ground point, known as the star ground point.
What happens if you separate a star ground?
If you were to separate their grounds, you will end up routing over the gap between the two reference planes, creating an undefined return path with large parasitic loop inductance. This area becomes a strong emitter/receiver of EMI. This situation is shown in the image below.
How does a star ground layout work on a PCB?
Star ground layout topology The star ground literally points to ground connections shaped like a star. Ground connections from different modules are connected to a point in the center, just like a multi-pointed star. It is quite similar to a single-point ground connection, except that the common grounding point appears in the middle of the PCB.
Why are there so many wires in the star ground?
The ground wires radiate away from the Star Ground in all directions, hence the name. This has the unfortunate result that you may have a HUGE number of wires coming into the Star Ground point. Very hard to wire, just because of the large number of wires.