I’m laying out my custom carrier board at the moment, and am a little confused regarding the USB3.0 common mode chokes used in the Ixora carrier board. The choke used is the DLW21SN900SQ2L, which has the following equivalent circuit:
[upload|80+gGG+E1gRqSYW35MNMBCtw/eY=]
My interpretation of this image, is that pads 1 and 2 are connected, and pads 3 and 4 are connected. However, the schematic for the Ixora shows connections between pads 2 and 3, and between 1 and 4:
[upload|EBjR/F+yEcj4Ys0Q23vS1kyeZsg=]
These connections are obviously reiterated in the Ixora layout:
[upload|VQSm9HC2phmztmEbd99iDpzNJ7g=]
The Ixora carrier board obviously works as intended, so I’m guessing I’ve just misunderstood the equivalent circuit?
thank you very much for using the Toradex developer community.
You are definitely right, the way this component has been added to the Altium library might be a bit confusing.
Nevertheless, it works because the pins are assigned in the same way in both the schematic and pcb library.
It is basically a different numbering approach but the equivalent circuit and the pcb footprint are perfectly fine.
I hope that I managed to clarify your doubts, please get back to me if you need further details.
