AnsweredAssumed Answered

AD698 excitation

Question asked by CamBuskell on Jul 5, 2012
Latest reply on Jul 5, 2012 by CamBuskell

Good morning.

I am looking to use your AD698 for a project to convert an LVDT signal.  I am struggling with the workings of this chip and have noticed some peculiar details with pin 2 and 3.


firstly, the wave shape I expect is severely distorted.  Instead of a sine wave, I'm getting something that resembles a switching spike in my wave.  Secondly, as my move the plunger in my LVDT, the excitation signal is changing in amplitude.  I don't know if the latter is normal operation for this chip or not.


I'm using this chip in single supply mode configuration.  My excitation signal does not change if I have a Vin of 18V to 32V.


My output of the chip is also not what I expect, but that's likely from the excitation being odd, or that I have the chip hooked up incorrectly. 


Any help you could offer in this matter would be appreciated.

Thanks for your time.