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AURIX™ Forum Discussions

EngAtRic
Level 1
Level 1
First reply posted First question asked First like given

To Whom it may concern,

I was wondering if you could provide me information about how to properly process the TUE and ENrms parameters for error calculation and ADC performance analysis on the SAK - TC37s µController. I have not had the chance to work on worst case analysis for ADC performance in long time and I need to refresh the process for proper analysis on this. I will appreciate all the information you can share about this topic. Thanks. Regards. 

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1 Solution
dw
Moderator
Moderator
Moderator
100 likes received 750 replies posted 10 likes given

Hi EngAtRic,

1) About ADC PCB Layout

The ADCs of AURIX™ require analog supply (VDDM) and reference (VAREF) voltages. Low pass filters for VDDM and VAREF pins are recommended for best ADC performance. Please see respective application notes for filter dimensioning - AP32362 A/D converter supply and PCB design guidelines for TC3xx - Analog supply / reference / input filter calculation, PCB and design guidelines

2) DC Input has below specs:
    a) offset error
    b) gain error
    c) differential non linearity
    d) integral non linearity
    e) total unadjusted error(TUE)

There is no definitive formula to calculate the maximum value of TUE for an ADC because the error is dependent on the input range at which the ADC is being operated. If the system does not require utilizing the entire input range of the ADC, you can minimize TUE by operating the ADC away from the end points of its transfer function.

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3 Replies
dw
Moderator
Moderator
Moderator
100 likes received 750 replies posted 10 likes given

Hi EngAtRic,

1) About ADC PCB Layout

The ADCs of AURIX™ require analog supply (VDDM) and reference (VAREF) voltages. Low pass filters for VDDM and VAREF pins are recommended for best ADC performance. Please see respective application notes for filter dimensioning - AP32362 A/D converter supply and PCB design guidelines for TC3xx - Analog supply / reference / input filter calculation, PCB and design guidelines

2) DC Input has below specs:
    a) offset error
    b) gain error
    c) differential non linearity
    d) integral non linearity
    e) total unadjusted error(TUE)

There is no definitive formula to calculate the maximum value of TUE for an ADC because the error is dependent on the input range at which the ADC is being operated. If the system does not require utilizing the entire input range of the ADC, you can minimize TUE by operating the ADC away from the end points of its transfer function.

EngAtRic
Level 1
Level 1
First reply posted First question asked First like given

Thanks for your input, I think I did not explain myself well so here it goes again: I don't need a formula to calculate the total error or maximum TUE. I already know the maximum TUE from the spec sheet (4 LSB) and I know the ENrms contributes as well, I guess the proper question is: how should I process those values to come up with the conversion values of the ADC? is there anything in particular those values should be processed to get the conversion values of the ADC? Is there an application note that explains how to use those values? 

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dw
Moderator
Moderator
Moderator
100 likes received 750 replies posted 10 likes given

Hi EngAtRic, for     a) offset error    b) gain error  it could be corrected for one case which could reduce the TUE also just for one case, but there is no details data for mass production. Other types of errors cannot be eliminated or corrected by software.

dw

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