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ADC Voltage Reference - Errors and Drift

Question asked by YYHH on Nov 22, 2011
Latest reply on Nov 23, 2011 by David.Buchanan

Hi,

 

I'm trying to calculate/understand if I need to use an external Voltage reference with my AD9255-105.

 

Ican read from the datasheet:

 

 

TEMPERATURE DRIFT

Offset Error Full ±2 ppm/°C

Gain Error Full ±15 ppm/°C

 

Is that Temperature Drift due to the internal voltage reference (then I could improve it using an external reference, if needed), or is it intrinsic to the ADC?

 

 

About the Maximum Gain Error:

 

The given data is

 

 

ACCURACY

Offset Error Full  ±0.25 % FSR

Gain Error Full  ±2.5 % FSR

 

The 2.5%FSR seems very big to me:

 

Gain Error
409.60LSB
25000.00ppm
2.5%

 

Have I done a bad calculation?

 

 

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