WHD72302G 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 WHD72302G puts it on the cable side, the WHD72301G 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. A five-port device carries five ports through EMC at once, so re-testing after a change costs far more than on a single-port part: test both orders at the prototype stage and stay with the choice.

One five-port device saves board area and part numbers, but ties all five ports together.

The WHD72302G body is 65.70 × 6.50 mm against five 16-pin single-port parts at 20.30 × 9.80 mm each — a large difference in area, and four fewer line items on the BOM. The cost is layout freedom: the five RJ45s have to sit along one line, and a fault on any port means replacing the whole device. Equipment with scattered port positions, or serviced port by port, is better suited by single-port parts.

A 65.70 × 6.50 mm body, 12.00 mm Max high; the leads span 58.74 mm and the two hole rows sit 3.30 mm apart.

Pitch is 1.78 mm and the recommended hole ø0.90 mm. The WHD72302G therefore needs a straight run close to 66 mm long but only 6.5 mm wide. With only 3.30 mm between the rows there is essentially no routing space in the middle, so each port's pairs have to leave from the two sides. The 12 mm clearance also needs checking; it is on the tall side among through-hole multi-port parts in the 10/100 BASE-T range.