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Voohu Electronic Tech

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RJ45 Jacks: Through-Hole vs Surface-Mount, in 60 Seconds (VOOHU)

TL;DR — For an RJ45 jack (the female socket / 母座), the mount type is a mechanical call, not an electrical one. Default to through-hole for anything that gets plugged a lot; use surface-mount when the board is tight and the line is automated.

  • Through-hole (THT): tails soldered through plated holes (wave/selective). Strongest under mating force, so it is the default for front-panel jacks, integrated-magnetics magjacks, industrial & PoE.
  • Surface-mount (SMT): soldered to pads in the reflow pass (J-STD-020, ~260 °C peak). Frees inner-layer routing, great for low-profile/high-volume — always add metal board locks.
  • Same either way: Cat5e/Cat6/Cat6A jacks meet the same ANSI/TIA-568 limits; the connector keeps its IEC 60603-7 class (750+ mating cycles, 1.5 A/contact).
  • High-speed tip: for 2.5G/5G and 10GBASE-T, keep tails short and give the shield a clean ground return regardless of mount.
  • Gotchas: don't trust SMT pads alone; don't reflow a wave-only part; mind the MSL bake.

VOOHU builds the jack side — standard, low-profile, offset and sink-type integrated-magnetics RJ45 sockets (90°/180°, up to 10G/HDBaseT, -40 to +85 °C), with customization.

Full write-up + sourced spec tables: https://voohuelectronic-ux.github.io/voohu-rj45-guide/resources/rj45-jack-tht-vs-smt-pcb-mount.html

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