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Adom Fields
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Adom Fields: where the current and the heat go on your board.
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John Lauer
adom-fields 0.7.13: capacitors as they sit on the rail. Technology from the MPN and footprint (electrolytic, polymer, t…
07a033f
adom-fields 0.7.13
- Capacitors as they really sit on the rail. The technology is read from the MPN and the footprint as well as the Value, so a "47uF 35V" Panasonic EEE-FK is an aluminium electrolytic with about 0.3 Ω of ESR, not a 3 mΩ ceramic; polymer, polymer tantalum and tantalum parts are recognised the same way.
- DC-bias derating for class-II ceramics. A 10 µF 25 V X7R 1206 holds about 3.5 µF at 12 V, and a 22 µF 10 V X5R 0805 about 10 µF at 5 V. With a measured curve for the MPN (Murata SimSurfing JSON, spec
capCurves), the measured C, ESR and ESL; otherwise an estimate fitted to those curves, labelled as such. - PDN and the converter's ripple both use it; the fix search derates new ceramics and also offers polymer bulk parts; ripple includes the ESR term.
- On the buck: the input electrolytic's ESR now damps the supply-lead resonance (VIN's 24 kHz peak is gone), and the output ceramics count 9.7 µF each at 5 V, not 22.
# adom-fields 0.7.13
- **Capacitors as they really sit on the rail.** The technology is read from the MPN and the footprint as well as the Value, so a "47uF 35V" Panasonic EEE-FK is an aluminium electrolytic with about 0.3 Ω of ESR, not a 3 mΩ ceramic; polymer, polymer tantalum and tantalum parts are recognised the same way.
- **DC-bias derating for class-II ceramics.** A 10 µF 25 V X7R 1206 holds about 3.5 µF at 12 V, and a 22 µF 10 V X5R 0805 about 10 µF at 5 V. With a measured curve for the MPN (Murata SimSurfing JSON, spec `capCurves`), the measured C, ESR and ESL; otherwise an estimate fitted to those curves, labelled as such.
- PDN and the converter's ripple both use it; the fix search derates new ceramics and also offers polymer bulk parts; ripple includes the ESR term.
- On the buck: the input electrolytic's ESR now damps the supply-lead resonance (VIN's 24 kHz peak is gone), and the output ceramics count 9.7 µF each at 5 V, not 22.