[![CAN architecture](https://i.stack.imgur.com/WiElNl.png)](https://i.stack.imgur.com/WiElNl.png)

I am using the [TI SN65HVD230DR](http://www.ti.com/lit/ds/symlink/sn65hvd230.pdf) CAN transceiver on two separate CAN buses between three microcontrollers (MCUs) -- two are on the same board, and one is off-board. This transceiver includes a Vref pin:

> 
> The Vref pin (pin 5) on the SN65HVD230 and SN65HVD231 is available as a VCC/2 voltage reference. This pin can be connected to the common mode point of a split termination to help further stabilize the common mode voltage of the bus. If the Vref pin is not used it may be left floating.
> 
> 
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Since the datasheet is terse with Vref details (How is it generated? Can two transceivers have Vref connected simultaneously?) I am not certain how to connect this pin. My intuition is to only have one transceiver connect Vref on the on-board CAN bus (CAN2 above) since the MCUs/transceivers are only a few cm apart.

For CAN1 between MCU1 and MCU3 (off-board) there will be 1~2 m of cable between them, so with the increased impedance my intuition is to connect Vref on both transceivers. Is this a fair assumption? Is there a better way?

**EDIT:** Forgot to mention I am using the split termination scheme at all transceivers.

[![Split termination](https://i.stack.imgur.com/cDsIq.png)](https://i.stack.imgur.com/cDsIq.png)