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ADC differential input protection

Question asked by Ahygoon on Oct 12, 2012
Latest reply on Oct 12, 2012 by MaryMc

Hello,

 

We know that the input coomon mode voltage should not be over the analog supply (~5V).

 

On the system, the differential lines could potentialy be short circuited to Ubat (12V) or sensor supply line (8V).

 

Against that, we will do a measure of the common mode voltage (with the ADC of the µC) at the start of the system and may be cyclically too.

 

We also want to add a protection on the signal line: 2 diodes

ADC_Input_Protection.PNG

Is it correct to do like that? I mean related to noise problem?

The ADC we want to protect will probably be a AD7195 (according to the advice from AD)

 

Do you have better solution?

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