Design Log DEC 013 l3 emi inductor changed to bourns srp1265a 100m - thepinkmile/Enigma-NG GitHub Wiki

DEC-013 - L3 EMI Inductor Changed to Bourns SRP1265A-100M

  • Status: ✔ RESOLVED
  • Date: 2026-04-03
  • Category: Electrical
  • Area: Power Module L3, PCB footprint

Decision

Replace Wurth 7447789100 with Bourns SRP1265A-100M as L3 (EMI DM Pi-filter inductor).

Rationale

  • Wurth 7447789100 is not available in any public distributor catalog (not found at DigiKey, Mouser, Farnell, or on the Wurth public website). Sourcing without a Wurth rep contact is not feasible.
  • Bourns SRP1265A-100M is a direct functional equivalent: 10µH, 15.5A Isat (exceeds 14.5A target with 21% headroom), DCR=16.5mΩ max (better than the original 20mΩ spec), shielded molded SMD.
  • Widely stocked: Farnell ~2,741 pcs; Mouser (652-SRP1265A-100M); DigiKey (SRP1265A-100MCT-ND).

Impact

  • ⚠️ Package footprint change: SRP1265A-100M is 13.5x12.5x6.2mm vs 7447789100's 12.5x12.5x6.0mm. PCB land pattern for L3 must use the Bourns 13.5x12.5mm footprint. Clearance to adjacent

    components should be checked during layout.