"Michael Terrell" wrote in message
...

On Friday, April 17, 2020 at 7:57:47 AM UTC-4, Jim Wilkins wrote:

Those capacitors weren't used in high frequency applications, and they
didn't pass as much current. Some CPU ICs operate at 1.8V at up to 100 amps.
All the ripple is passed to the ground plane as those capacitors filter the
rail. Multiple capacitors in parallel are used for several reasons. They are
smaller, so each one generates less heat. A cluster of them have a mower ESR
than a single capacitor. They can be a lot closer to the CPU to improve
voltage regulations, and reduce the radiated noise....
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On one-off military and FAA digital radio prototypes where GHz-range
performance was more important than production cost I used tantalums for
distributed bulk capacitance and 0.01uF paralleled with 0603 or 0402 1nF MLC
chip caps, typically on the bottom of the board under the device, as close
to the power vias as possible, and sometimes overlapping them which I could
get away with since I soldered everything myself. We based this on network
analyzer sweeps of the capacitors and graphs like these:
https://electronics.stackexchange.co...mic-capacitors

I developed some seemingly impossible stunts like joining solder into small
closed rings, formed into chain mail. One of my tricky bits of prototype
handicraft unintentionally found its way into the production Segway.
Somewhere a Chinese girl with tired fingers is cursing me.


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