NNTP-Posting-Date: Fri, 25 Oct 2002 19:55:05 -0500
From: "Dave VanHorn"
References: <3DB96152.1393B701@rica.net> <3DB9800A.780B223E@rica.net> <3DB9C8F4.5A42BD61@rica.net>
Subject: Re: Bypass capacitor position
Date: Fri, 25 Oct 2002 19:55:42 -0500
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> But you still describe 3 reactances in series, not in a tee structure.
> Here is a chip with a bypass capacitor and some trace inductance. How
> is this a tee filter?
> | |
> [c ] I
> [h ] |
> [i ] C
> [p ] |
> [ ] I
> | |
I don't make any other connection to the chip's VCC lead. It goes to it's
bypass, and nowhere else. So, you get a tee filter, with the chip as the
output load, if you will..
> You could reduce the noise between different sections if you gridded
> the ground
I could let return currents pick their own path instead of controlling them,
and they might run by cable grounds, so that when I attach a cable, it
becomes an antenna.
Bleagh.. When my chopped stepper driver takes current from the main PS cap,
it shall return it therefore, and directly, to whence it came. Neither
shall it be allowed to wander hither and yon about the board, leaking off
the foul vapours of EMI as it searches for a path home, for it's path shall
be golden, broad, and well defined.
>and 5 volt tree structure into a mesh work. And lower the
> emissions some more.
I don't think so.
> John Popelish