AnsweredAssumed Answered

AD620 Signal Out problem

Question asked by JerryS on Oct 21, 2014
Latest reply on Oct 22, 2014 by krisf

Hello,

 

my customer has a application with wheatstone bridge front of AD620, and set Gain= 800 as input signal is much smaller.

According to PCB size and cost consideration, I would like to use signal supply Vs+= +10V, and Vs-= 0V as below diagram.

I have done two method for test, but AD620 output seems to abnormal with signal supply.

Would you please kinldy help to double check it and give me some of suggestions? Thank you.

Condition and waveform as below.

 

a. Vs-=0V, Vs+=12V, Vref= +6V, Gain = 800, result: Vout abnormal.

b. When Vs= -5V, Vs+= +5V, Vref = 0V, Gain=800, Result: Vout is normal.

 

 

1.jpg

 

 

a. Vs-=0V, Vs+=12V, Vref= +6V, Gain = 800, result: Vout abnormal.

      Vout range should be -Vs+1.4V ~ +Vs-1.3V

   

1.jpg


b. When Vs= -5V, Vs+= +5V, Vref = 0V, Gain=800, Result: Vout is normal.

2.jpg

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