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AD8655 current noise

Question asked by crismarra_polimi on Jul 20, 2017
Latest reply on Jul 24, 2017 by iamPhil

Searching information on AD8655 current noise on this website (nothing is found in the datasheet) I find this kind of answers:


"On CMOS op amps, the current noise is very, very low. It's usually negligible.  That's why you don't see it on the datasheet. The current noise for the AD8665  is in only tens of fA/rt-Hz"


From my point of view a current noise of 'tens of fA/rt-Hz' is not 'very,very low'.

For AD8065 you declare a current noise of 0.6fA/rt-Hz, more than an order of magnitude lower! Why in the case of AD8655 the current noise value is not declared?


It is very useful to add this information in the datasheet of AD8655: if someone want to use this operational amplifier in a trans-capacitance configuration, e.g. for the readout of a MEMS sensor, the current noise contribution can easily dominate!