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MOSFET to switch termination resistor in CAN bus network

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wlamers

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What would be the best method to switch a pair of 60ohm or one 120ohm termination resistors on the end node of a CAN bus on and off? Could I use a MOSFET here? The source is not attached to ground since CAN is a differential pair. How would the schematic look like? ESD is also an issue here.
 

The specifications are simple: The switch must be bipolar and bear the maximum common mode rating of a CAN transceiver, e.g. +/- 40 V.

Can be done with a MOSFET pair and a control voltage of sufficient swing. If you don't require correct switch operation at high common mode voltages (the CAN transceiver won't work beyond +/- 12V either) and place a low pass filter and voltage limiter for Vgs, this might work.

A PhotoMos or electromechanical relay is probably the more straightforward solution.
 
FvM said:
A PhotoMos or ... is probably the more straightforward solution.
Click to expand...

That would be a perfect solution due to its LED isolation. Altough these PhotoMOS relays seems to be pricey...

I end up with this schematic. Is this what you mean?

CAN_photomos.jpg
 

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