LM3414: Ground connection for Cvcc and Riadj

David Dean

Part Number: LM3414

I see in both the LM3414 datasheet and eval board that the ground pins of Cvcc and Riadj are connected to a top-level ground plane. Is this required or recommended for any particular reason? Or just a fluke of the layout? I can understand the advantage of a direct GND connection to Cin, rather than through a via, but perhaps this is not really needed for these two components?

over 7 years ago

0 Irwin Nederbragt over 7 years ago

TI__Mastermind 28655 points

Hello David,

It's not necessary but good layout practices should be followed.

Best Regards,

0 David Dean over 7 years ago in reply to Irwin Nederbragt

Expert 2325 points

Thanks Irwin. I guess that's the question - if those signals were high current, or high frequency, or sensitive, then Good Layout Practices would be to tie it to a top-layer ground plane. Is the answer that these signals are not in that category? If I use a via it would still be a short trace and go directly to a bottom layer ground plane.

0 Irwin Nederbragt over 7 years ago in reply to David Dean

TI__Mastermind 28655 points

Hello David,

That is fine. The Vcc capacitor supplies the gate drive for the MOSFET so there are pulses of current coming from it but it is not a critical signal. Riadj, if you have a ground plane I would be fine with a via to ground, even a little trace won't hurt that signal. Just like all layout, you strive for the best even if it isn't necessary.

Best Regards,

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LM3414: Ground connection for Cvcc and Riadj