Nineteen signal pads need thirty-one pads on NanoSoC, and the twelve extra are not margin: they are the supply pads that carry the current and keep the switching noise inside its allowance. This topic prices those twelve: how many supply pads a current needs, how much simultaneous switching one I/O supply pair tolerates, and how pairing and drive choices close the loop. Its one job is the count and the noise; the package topic spends the pads on balls, and the power-delivery topic spends the current on resistance.
Lesson | After it you can... |
|---|---|
Budget NanoSoC pads from current and decide whether the die is pad-limited or core-limited. | |
Run the SSO allowance as a calculator input and pass or fail a switching pattern. | |
Pair every output with a nearby return and see why a fast drive is not free. |
Suggested order: top to bottom. The budget first, because the noise lesson consumes the supply-pair count; then the noise check; then the pairing and drive choices that make the check pass. All three reuse the 31-pad ring of the previous topic unchanged.
Because current and noise cost pads too: the core supply needs pads sized by current, and the I/O supply needs pairs sized by how many outputs may switch together. Signals are only the start of the count.