Re: gEDA-user: bypass caps

[DJ Delorie <dj@xxxxxxxxxxx>]

Ok, in all fairness, my fault for not specifying the project (not the
furnace controller this time).

I'm working on a simple sram/ethernet add-on card for one of my m32c
starter kits.  It's a 2 layer 3.5x4.5 board, 32MHz signalling, and the
power and ground are "tree structure" - i.e. no planes (won't fit) -
with 20 mil traces (signals are 8 mil).  Heck power and ground enter
the board about 3" apart on the connector!  (yes, they put one on each
end).  This fab will also have the challenge boards on it, so 4 layer
is not an option.

Each of the eight 512k SRAM chips have two power pairs, so two bypass
caps.  The ethernet chip gets three at the chip, and two more (larger)
around the 3.3v regulator.  Plus one for the 3:8 address decoder.

But it sounds like 0.1uF at the power pins and a few 1uF elsewhere
would be ok?  The m32c board itself has a 100uF after the 7805.


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