AnsweredAssumed Answered

AD780 Noise ?

Question asked by JDanG on Apr 17, 2014
Latest reply on Apr 21, 2014 by KarenNE

Hi,

 

I am having trouble verifying the noise level in the AD780.  I have an AD780BRZ mounted to a prototype PCB with 1uF ceramic input cap, 0.01uF ceramic cap on the TEMP output and an 10 uF ceramic output cap.  I am using an HP Dynamic Signal Analyzer (yes, I am one of those "old analog guys") to look at the output in the frequency domain.  I see about 15 uV @ 1 Hz.  I thought I should see 4 uV.  I tried removing the output cap expecting a rise in the noise, but the results are the same.  I have found a newer, lower noise part - ADR441 that I have on order, but I wanted to ask about the AD780 just to close the loop.  Any ideas?  Thanks.

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