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John Lauer 0.9.6: inputs a solve assumed (datasheet fields, spec patch), reflections and TDR 4271eae

adom-fields 0.9.6

  • The inputs a solve assumed (review.inputs).
    • What it lists: every default or estimate the results lean on, most important first, each with the part and MPN, the datasheet field that replaces it, the spec key, and what moves (with a sensitivity where one can be computed).
    • specPatch: the spec fragment for an AI to fill from the datasheets.
    • On the TPS54202 buck: 14 medium items (the capacitors' DC-bias capacitance, the electrolytic's ESR, U1's θJC, the laminate Dk, cable lengths, PDN load steps) and 4 low.
  • Reflections and TDR (review.reflections).
    • The model: each checked net's path from driver to receiver, its segments as lines with the cross-section solve's Z0 and delay, and its vias as pad capacitance.
    • Two ngspice runs: a 50 Ω TDR profile, and the real driver's overshoot, ringing and series termination.
    • Which nets: impedance targets, clocks, length groups, and spec tdr.
    • On the ESC's SWD clock: 40 % overshoot with a 0.5 ns edge, so a 38 Ω series resistor goes at the MCU pin.
  • Fix: impedance segments' psPerMm is in ps/mm (it was a factor of 10⁶ off).