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AD5165 digi pot - is the graph believable?

Question asked by Andyaka on Nov 26, 2015
Latest reply on Dec 21, 2015 by Andyaka

On the front page of the data sheet it tells me that the temperature coefficient of the resistance in the digi pot is 35ppm/C and in the table on page 3 it says the Voltage Divider Temperature Coefficient is typically 15ppm/C.

 

No problems so far and the device looks OK but because of my application I have to look for the graph that shows me the temperature coefficient versus wiper position and, from experience the tempco with low codes (wiper close to one end) usually gets seriously worse. What I see is this graph on page 9: -

 

Untitled.png

It looks too good to believe so my question is this: -

 

IS THERE AN ERROR IN THE DATA SHEET?

 

For instance, if I look at a slightly different device the AD5280 the front page tells me it is 30ppm/C and in the table on page 3 it says the Voltage Divider Temperature Coefficient is typically 5ppm/C (seriously better than the AD5165) but the graph shows this: -

Untitled.png

In other words it is significantly worse at low wiper codes.

 

Can anyone help me with this?

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