WHD20702G 10/100BASE-TX LAN Transformer

The two match on electrical ratings and hole pattern, so choose purely by which side the common-mode choke should land on: the WHD20702G puts it on the cable side, the WHD20701G on the chip side.

The deciding factor is the element order in the PHY reference design and the EMC result on the finished unit, not a better or worse number — the parameter table shows no difference. Swapping after the board is fixed costs no footprint work but does need EMC re-measured.

Not at all. The WHD20702G is 2.00 mm pitch with an 18.00 mm span on a 21.20 × 10.00 mm body; the 2.54 mm family spans 22.86 mm on a 25.40 × 10.00 mm body.

All twenty hole positions differ and the body is 4.2 mm longer. Row spacing does happen to be 7.62 mm on both, but matching row spacing alone means nothing — the hole-to-hole interval differs, so every hole in the row is displaced. Where board length is tight the 2.00 mm family saves space; where an existing 0.1-inch-grid board is being reused, the 2.54 mm family is the one.

Indoor dual 100M port equipment where the component temperature stays between 0 °C and +70 °C and the PCB carries a 20-pin through-hole layout on 2.00 mm pitch with 7.62 mm row spacing.

The WHD20702G has no PoE capability, so both ports are powered locally; the body is 21.20 × 10.00 mm, 7.20 mm Max high, with 3.20 mm leads, wave-soldered. A board drilled to 10.16 mm row spacing cannot take this part — see the 10/100 BASE-T range for that outline.