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AD7147:  AC_SHIELD

Question asked by Mr.K on Sep 28, 2012
Latest reply on Oct 22, 2012 by spratt

I have a question about AC_SHIELD of AD7147.

 

I'm using two AD7147 on one PCB.

Each AD7147 is connected with the sensor of the slider.

In this system, the CIN value of default is greatly different in each PCB.

In the device with large CIN value, the default value is 9bit level.

In the device with small CIN value, the default value is 3bit level.

 

In my evaluation result:

When the AC_SHIELD frequency value of two AD7147 is close, the default CIN value is large(9bit level).

When the frequency value is far, the default CIN value is small(3bit level).

In my system, AC_SHIELD plane and another AC_SHIELD plane are adjacent.

In this AC_SHIELD plane layout, does the above issue occur when each AC_SHIELD frequency is close?

 

The AC_SHIELD frequency of AD7147 is 250KHz(typ) in the data sheet.

I want to know the maximum value and the minimum value of the AC_SHIELD frequency.

 

Regards,

Mr.K

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