ISO124: DESIGN SUPPORT

Thank you for the reply..

Dear Tom Hendrick,

I was partially tested iso124u. input is ~0v,output is -17mV.  Please clear the doubt , is there any chance to get negative voltage on the output during power on?

You are suggested iso224. this is good ic  but output range is 2.5v to 3.3v. difference is 0.8v (adc measuring range) .might be difficult to give the accuracy of moving plate in mm.

How is U31 powered?  You need headroom on the ISO124 for both the input and output side.  The ISO224 output gain is 1/3, so you could potentially remove the divider on the input.

Dear Tom,

Am giving 24vdc single ended power supply to U31. potentiometer-wiper output range is 0-24v.  am using STM controller with adc vref is 3.3v only. So i need the range 0-3v(safe). u31 output is same as input that is input 5v given and getting output 5v(buffer circuit) and  i applied  -1v to non-inverting terminal for R&D, i got Vout is mv (positive). input of iso124  is positive.

input of iso124= 0v and output is -17mv i measured.  i explained  my circuit and have a doubt about negative voltage is coming at output or not? if any chance is there i will change the circuit diagram because now  am doing the  pcb design  .after sending of manufacturing not possible to update immediately. so please clear the doubt as early as possible. Thank you for your support.

You could try differnt test conditions - maybe cycle -Vs before +Vs and see if that is going to have an impact on your output.

Hi Tom,

Testing with the above power‑up cycles confirms the working status, which is acceptable. As a customer, we expect this validation from you, rather than being asked to perform the tests ourselves. Thank you for your support.