AnsweredAssumed Answered

AD630 giving me an offset at the output

Question asked by SamMaster on Jan 5, 2017
Latest reply on Jan 11, 2017 by SamMaster

Hello,

I'm using AD630 as lock in amplifier and it is giving me an offset at the output. I want to remove that offset and I don't know how it gets there.

I will explain my conditions of the circuit.

My input signal is noisy sine wave(it does not contain a dc offset).

   -I figured out that if I'm giving an input signal which has offset It will give me amplified offset at the output. So I guess it can not be the problem.

 

My sync(reference) signal is a 0-5V square wave derived from a sine wave. It should have 50%(closely) duty cycle. It contains no offset.

   -I figured out if there is a offset in the ref signal AD630 giving an offset at the output.

 

I'm wondering what could cause me to have a offset at the out put. Can I adjust a offset from the AD630?.

I followed the circuit diagram of AD630 FIGURE 35.

 

LINK TO DATASHEET

http://www.analog.com/media/en/technical-documentation/data-sheets/AD630.pdf 

thanks.

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