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An issue about ADN8831

Question asked by hpkamen on Oct 18, 2015
Latest reply on Oct 19, 2015 by ytu

Dear  Sir/Madam,


I have some issues about ADN8831. Our board has multi channels, using multi AN8831, and only one could not operate correctly.


quetion 1:


I am using ADN8831, because the temperature measured is  positive temperature coefficient, I configure the error  OP as a follower, and other circuit follows the EVB.

After power on, measure voltage of PIN14 SS/SB,  and it is always low(0.125V or 0.190V), the output of TECP and TECN  also near zero. Vref voltage is normal,  TEC  voltage, Vvtec, Vitec are all normal.  Condering all above, i suppose the chip gets into standby mode.


   I wonder to knonw
   

  (1) Is this status  standby mode. if it is so, what other reasons  could lead to getting into standby mode.

 

  (2)what should i do to handle this problem.

 

  (3)when i measure PIN 14 voltage, if i use the multi-meter PIN 13 first, and then measure PIN14, the voltage will drop from 3.3V to 0.2V.  Is this normal


  (4)I tried another chip which also has such problem, finding if i remove 0.1uF cap from PIN 14,  the chip could heart but not cool.  Is the chip damaged or anything else.

    Question 2:

 

    Other channels could work correctly,  but  i found the setting value of voltage-limit  and current-limit, is not same as i measure.   i wonder is this normal.


thanks.


 

 

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