ABCs of ADCs - Analog-to-Digital Converter Basics (PDF)

Linearity - DNL (DLE) andINL (ILE)• DNL - Differential Non-Linearity• DLE - Differential Linearity Error• INL - Integral Non-Linearity• ILE - Integral Linearity ErrorDNL and DLE are the same thing and describe the error instep size. This is “small scale” code to code errors.INL and ILE are the same thing and describe the bow in thetransfer function. This is “large scale” overall transferfunction error.12DNL and DLE are different terms used to describe the error in step size. Similarly, INL and ILEare different terms used to describe the maximum deviation from the ideal transfer function.The key to remembering the difference between these two specifications is the word“Differential”. DNL is the difference between the ideal and the actual input code width. Theinput code width is the range of input values that produces the same digital output code. Forpositive DNL we look at the widest input code range. For negative DNL we look at thenarrowest code range.INL is the maximum deviation of the transfer function from a straight line between two pointsalong the input-output transfer curve.ABCs of ADCs - Rev 3, June 2006Authored by: Nicholas “Nick” Gray12Copyright © 2003, 2004, 2006 National SemiconductorCorporationAll rights reserved