WHSG24303G Gigabit LAN Transformer

Not as a straight swap. The suggested land patterns of the WHSG24303G and the WHSG24301G match value for value and both bring the centre taps out on the same pins, but their schematics place the common-mode choke on opposite sides. On the WHSG24303G the isolation transformer sits next to the 13 to 24 pin row with the choke next to the 1 to 12 row; on the other part the arrangement is reversed.

Which row faces the RJ45 is decided by the board, so fitting the other part to the same land pattern moves the choke relative to the cable and the PHY, and the EMC result does not carry across. The two also differ in storage range. Confirm the orientation on your board and repeat EMC verification against whichever part is fitted.

Watch that the centre taps of the WHSG24303G are grouped in adjacent pairs rather than sitting beside their own differential pair: TXCT1 is on pin 22 while the channel 1 pair is on pins 24 and 23, and TXCT2 is on pin 21 while the channel 2 pair is on pins 20 and 19. The lower row follows the same pattern, with TDCT1 and TDCT2 on pins 3 and 4 while channel 1 runs on pins 1 and 2 and channel 2 on pins 5 and 6.

Wiring straight down the pin order easily treats pin 21 as part of the channel 2 pair when it is in fact that pair's centre tap. The WHSG24303G prints the channel number into each net name precisely so this mapping can be checked at a glance; work from the net names and pin numbers on the drawing. Related parts are listed in the 100/1000 BASE-T range.

The WHSG24303G is rated MSL Grade 1 with a floor life of 0.5 year at 30 °C and 60% RH or below, and reflows to a peak of 250 °C plus or minus 3 °C. The rest of the profile calls for a ramp-up of 3 °C per second maximum and a ramp-down of 6 °C per second maximum, 60 to 150 seconds above the 217 °C liquidus, and no more than eight minutes from 25 °C to peak.

Grade 1 means no separate bake is needed for the WHSG24303G while it stays within its floor life under controlled conditions. The current datasheets for the other two parts in this package do not publish a reflow profile or a moisture sensitivity level, so ask VOOHU for their controlled conditions separately rather than applying these figures to them.