KSZ9031RNX

Microchip · Gigabit Ethernet transceiver (10/100/1000BASE-T PHY) with RGMII MAC interface · QFN-48 7x7 mm (5.15 mm EP)

Single-port triple-speed Ethernet PHY in a 48-pin 7 x 7 mm QFN with a 5.15 mm exposed pad (0.5 mm pitch). The natural partner to the LAN7800 on the copper side of a design. This page carries the KiCad set — symbol, footprint, STEP/GLB — plus the Adom footprint-variant family: the baseline land pattern and its generated variants for heatsink vias, 300 µm jet-pasted solder balls, and rounded-rectangle pads.

Footprint variants

Explore each variant below — the interactive view is parsed live from this page's .kicad_mod files. Anything a variant adds or changes against the baseline is outlined in accent.

Why these variants exist:

• Heatsink vias (-HV) — 16 plated thru-hole vias under the exposed pad (1.2 mm pitch, 0.3 mm drill, 0.6 mm annular), all numbered 49 so they share the EP net with no symbol change and clean DRC. They pull heat from the EP into the inner planes.
• Solder balls (-SB) — filled circles Ø0.30 mm on User.9 (Adom.SolderBalls), one per 300 µm jet-paste ball, marking exactly where Adom places solder on the pads and EP (perimeter ring plus a ring around every via position).
• Rounded pads (-RR) — every SMD pad becomes a KiCad roundrect (signal pads rratio 0.25, EP 0.1), the Altium-style land pattern. A sharp pad corner is a stress riser where copper foil fatigues and peels from the FR4; a rounded corner — like an airplane window — spreads the stress, so the joint lives longer through thermal cycling.
• Combined (-HV-SB-RR) — all three applied to one production-ready footprint.

The family was generated with footprint-widgets/tools/make-variants.py, which reproduces the adom-footprint heatsink / solderballs rules.

Pinout

Hovering a pad in either widget cross-highlights the same pin in the other (the shared adom-lbr hover bus).

Key specifications

CAD

• Symbol: ksz9031rnx.kicad_sym (49 pins, KiCad official KSZ9031RNXCA)
• Footprint (baseline): ksz9031rnx-qfn48-7x7.kicad_mod
• Footprint variants: -HV, -SB, -RR, -HV-SB-RR
• Variant manifest: ksz9031rnx-qfn48-7x7.variants.json (+ heatsink-vias.json, solder-balls.json rule files)
• 3D model: ksz9031rnx.step / ksz9031rnx.glb

Provenance

• Symbol: KiCad official library Interface_Ethernet:KSZ9031RNXCA (CC-BY-SA 4.0). Pin names and electrical types come from it; per-pin descriptions are not reproduced here — see the datasheet.
• Footprint: KiCad official Package_DFN_QFN:QFN-48-1EP_7x7mm_P0.5mm_EP5.15x5.15mm (CC-BY-SA 4.0). The baseline keeps KiCad's pad geometry but draws square pad corners and a full-paste exposed pad (KiCad's 16-aperture paste split is replaced by the Adom solder-ball layer, which defines paste placement); the -RR variant restores KiCad's roundrect corners.
• 3D model: KiCad official Package_DFN_QFN.3dshapes/QFN-48-1EP_7x7mm_P0.5mm_EP5.15x5.15mm.step; GLB via step2glb.
• Variants: footprint-widgets/tools/make-variants.py, verified bit-for-bit against the adom-footprint 1.0.22 output on adom/lan7800.
• Datasheet: Microchip could not be mirrored here (their file handler refuses non-browser fetches); document DS00002117 on the product page.