AnsweredAssumed Answered

AD7476A analog input over-voltage protection

Question asked by werty on Apr 19, 2014
Latest reply on May 25, 2014 by KarenNE

The absolute maximum ratings for the analog input in the AD7476A's datasheet say 0.3V beyond the rails (0V-5V in my case). If the analog signal is driven out of this range by a +/-12V powered op-amp (not ESD!), what is necessary to adequately protect the input?

 

For example, it's a common practice to have a 4.7k or 10k resistor to limit the input current, then have external (to the IC) diodes clamp the voltage to near the rails. In some cases the IC has internal clamping diodes and only the current limiting resistors are necessary. In the case of clamping diodes, since it's only 0.3V that are the absolute maximum, it sounds like I might need some pretty low forward voltage diodes.

 

I look forward to your answers!

Outcomes