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A/D input voltage limit?

Question asked by Reson8r on Oct 11, 2011
Latest reply on Nov 11, 2011 by AndyR

The AD9649 A/D has an analog supply voltage AVDD of 1.8 V.  The analog inputs are spec'd at absolute max of -0.3 to AVDD + 0.2.  Yet the recommended differential drivers for this A/D (ADA4937, etc) have minimum supply voltage of appx 5V and an output swing which exceeds the A/D input max.  During power-on or input overload the A/D would easily see greater than its absolute max voltage on its VIN inputs.  There is no protection against this shown in the A/D typical circuits.  Is this something I need to worry about?  If not, why not?

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