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I am examining the Analog Devices AD74413R and came across a symbol in the evaluation board schematic I am not familiar with. There are small parallel lines around connection lines in various sections of the following schematic:

Excerpt from AD74413R Evaluation Board Schematic

These seem to be used primarily with ground connections, such as this star ground section:

AD74413R star ground section

(Documentation/datasheet)

Since this IC is a sensitive A/D converter, my best guess is these symbols are meant for shielding or filtering, such as a ferrite bead. However there are no designators nor components associated with the symbol nor any hints in the BOM. What are these symbols indicating?

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2 Answers 2

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These are net ties. They indicate that two nets with different names are directly connected together.

If you look closely at your schematics, you can see that the nets on either side of every one of these symbols have different, explicitly given names.

Sometimes they also have an associated footprint, in which case they're also useful to define an explicit physical connection point of two nets on the PCB, like with your star ground.

Check out Andy aka's answer as well as this might be a case of a schematic symbol being used for the wrong purpose.

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    \$\begingroup\$ Mystery solved, this makes total sense as I've been implementing them in my design just the same and never made the ... ahem ... connection. Thanks! \$\endgroup\$
    – JYelton
    Jan 6, 2023 at 22:27
  • \$\begingroup\$ I think I'd agree that these are supposed to be net ties, and perhaps Analog is using the wrong symbol for that. A cursory search for a net tie symbol turns up a lot of differing results. \$\endgroup\$
    – JYelton
    Jan 7, 2023 at 0:04
  • \$\begingroup\$ I wonder if the symbol is intended by the people who put it in the software to map to either a ferrite bead component or to a component which adds a keep-out between the two pads along with copper that is invisible to the design-rule checker. \$\endgroup\$
    – supercat
    Jan 7, 2023 at 18:13
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They match ferrite bead symbols as per this: -

enter image description here

Image from here.

See also this Q and A on North American standard symbol for ferrite bead.

Also found on Electrical & Electronic Symbols: -

enter image description here

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    \$\begingroup\$ I had found that symbol in my search as well, but I wasn't convinced that was how Analog was using it. Thanks, Andy! \$\endgroup\$
    – JYelton
    Jan 7, 2023 at 0:02
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    \$\begingroup\$ @JYelton the thing is this: the only place you'd likely use FBs are on power or GND lines. I didn't see occurrences of any used on other nets but, maybe you have more information? \$\endgroup\$
    – Andy aka
    Jan 7, 2023 at 10:28

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