ADM1278 / ADM1172 current shunt and Temp-pin question

Dear Sir,

      

      Below questions need your help:      

1. We find that ADI’s sense resistor layout guide as below link. It will be improved 1% accuracy of voltage sense as recommendation as below.But the test condition is 20A. My application is almost 60A current flow for ADM1278. The result will the same? For ADM1172,I route the current sense with the shortest path, but the recommendation is the longer path and have via ,what is your idea?

Optimize High-Current Sensing Accuracy by Improving Pad Layout of Low-Value Shunt Resistors | Analog Devices 

  1. Base on ADM1278 spec suggestion, add Low-pass filter on pin25 (Temp-pin) is needed. But the sensor location is closed to controller regarding to currently layout now, do I need it?
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    •  Analog Employees 
    on Jan 17, 2017 2:41 AM

    1. we have had success with this approach upwards of 100A. but it is very resistor model  dependant. i recommend testing a resistor for accuracy on earlier revisions and optimizing as the project progressed. If results are poor, optimized sensing points can be found by passing a controlled current and measuring various points with needle probes. 

    2. for this proximity it should be ok without. but i recommend placing the component footprints for the filter just incase. 

Reply
  • 0
    •  Analog Employees 
    on Jan 17, 2017 2:41 AM

    1. we have had success with this approach upwards of 100A. but it is very resistor model  dependant. i recommend testing a resistor for accuracy on earlier revisions and optimizing as the project progressed. If results are poor, optimized sensing points can be found by passing a controlled current and measuring various points with needle probes. 

    2. for this proximity it should be ok without. but i recommend placing the component footprints for the filter just incase. 

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