Dear All,

Please let me know about Total Unadjusted Error(TUE) of AD5421.

Although Table2 in a data sheet shows C-Grade, isn't there the specification for B-Grade?

Although figure14 seems to be C-Grade, doesn't Fig for B-Grade have it?

We want to use the product of B-Grade.

These are required for us.

Best Regards,

DMN

Hi DMN,

Again, my apologies for the delay.

We only have data for the C-Grade with the internal reference. If you are interested in other grades, then you will have to add the effect of the internal reference.

The calculations in table 1 assume an ideal 2.5V reference, a real reference will have an initial accuracy and temperature coefficient.

Let's use the internal Rset TUE specification, as it already includes the effect of the internal resistor and add the influence of the internal reference.

There are two ways to calculate:

You can add the errors together. This is the absolute worst case as you are adding the maximum deviation of the reference and TUE. In general, the accuracy will be much tighter.

= 0.18% + 0.12% + (0.0008% x 145C)

= 0.416% FSR

For a more optimistic error calculation, some use Root Sum of Squares:

= sqrt( (0.18^2) + (0.12 ^ 2) + ((0.0008 x 145C)^2))

= sqrt (0.0324 + 0.0144 + 0.013456)

= 0.245% FSR

Hopefully this helps, please let us know if you have any further queries.

Kind Regards,

David