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Design >> Analog Design >> Total error of a bandgap in mc
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Message started by melinda on Jun 10^th, 2013, 12:15am

Title: Total error of a bandgap in mc
Post by melinda on Jun 10^th, 2013, 12:15am

Hi,
I want to calculate the total error of a bandgap reference . I think the error of a reference are given by the error of Vbe, the error of deltaVbe, the error af an opamp (offset) and the error of the resistive ratio.
Please can anyone tell me if there are others error and if the total error is equal to the geometric mean of all the errors ?

Title: Re: Total error of a bandgap in mc
Post by tzg6sa on Jun 11^th, 2013, 2:10am

Yes, these are error sources. I think you listed all parts of the bandgap circuit :)

The general procedure to obtain the mismatch is to
1. derive the formula for your output parameter, and then
2. differentiate it for all parameters which are not constant.
3. Add the error values (for example dR/R=1%) --> to get stdev for every error ource
4. Sum the square of the standard deviations if the error sources uncorrelated to obtain the square of the standard deviation of the whole circuit