[time-nuts] Testing the TAC, and a question about ADEV

Fabio Eboli FabioEb at quipo.it
Sat Dec 29 10:28:20 UTC 2012

> http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=4030739&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D4030739 
> <http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=4030739&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D4030739>

> is one of the best in that it gives guidance on selecting suitable 
> test oscillator periods.
> It also details how the integral linearity can be derived from the 
> test.
> There are a couple of minor errors in the paper.
> Bruce

Thank you for the references, unfortunately I dont
have an account to access to IEEE papers.

>> P.S. The micro's adc is charachterized
>> for total unadjusted error of +-2LSB Max
>> at 25°C, 12bit total.
>> It's s-h is 8pF with 1kohm in series,
>> probably I can sync the sampling to
>> open just before the pulse, and close
>> after the fact.
> What error is that:

As per the datasheet blah blah :) :
"the total unadjusted error (TUE) is defined as the
maximum deviation between the actual and the ideal
transfer curves. It is a parameter that specifies
the total errors that may occur, causing maximum
deviation between the ideal digital output and the
actual digital output. It is the maximum deviation
recorded between the ideal expected value and the
actual value obtained from the ADC for any input voltage."

pag 9, I was considering it the worse case error.

> gain error?


> offset error?


> integral nonlinearity?


> What about monotonicity or differential linearity?


See :
pag 76

> A worst case assumption would be that the ADC is perhaps only
> monotonic for the 11 most significant bits.


More information about the time-nuts mailing list