There's no rocket science in CAN transeivers.

Normally reference voltages are acheved using simple voltage drop circuit or linear volatage regulator.

Note, as there may be large voltage drop between transmitter and receiver grounds (80 V AFAIK) there's no need for precise 2.5 V. Low voltage transceivers use lower common-mode voltage.

So only differential voltage of ±0.5 V is actually regulated, and common mode voltage can be set by simple voltage divider.

There's some interesting schematics on a page: http://www.ecnmag.com/articles/2009/10/isolated-can-transceiver-assures-robust-fieldbus-design

Note diodes feeding CANL and CANH. Together with output transistors they give about 1.5 V drop. (They also protect transistors from reverse current)

There's no rocket science in CAN transeivers.

Normally, reference voltages are achieved using a simple voltage drop circuit or a linear volatage regulator.

Note, as there may be a large voltage drop between transmitter and receiver grounds (80 V AFAIK) there's no need for precisely 2.5 V. Low-voltage transceivers use a lower common-mode voltage.

So only a differential voltage of ±0.5 V is actually regulated, and the common mode voltage can be set by a simple voltage divider.

There are some interesting schematics in the article Isolated CAN Transceiver Assures Robust Fieldbus Design.

Note the diodes feeding CAN-Low and CAN-High. Together with output transistors they give about a 1.5 V drop. (They also protect the transistors from reverse current.)