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AD7685 input voltage protection

Question asked by PDES on Feb 6, 2012
Latest reply on Feb 7, 2012 by maithil

Hi all,

 

I need to convert a signal obtained from an AD8226, wich is powered with +24V, using an AD7685.

The output signal of the AD8226 is normally in the range 0-2.5V but can reach the +24V under a fault conditions.

The datasheet of the AD7685 indicates a maximum voltage input of VDD+0.3V or a maximum current of 130mA.

In order to protect the ADC against the overvoltage, it's preferrable to use a current limiting resistor followed by a buffer, in way that the input resistance see from the ADC is not so high, or the buffer can be avoided ?

 

Thanks in advance

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