Hi,

This is regarding measurement of offset value of ADC.

Can any body tell me whether do i need to consider the value of DNL while calculating offset value.

The standard equation for calculation is offset=Tp(1) - 1LSB where Tp(1) is the 1st transition point of a staircase digital output. Do i need to consider the DNL value of that code while measuring the offset value i.e. is the following equation correct for measurement of the offset error of an ADC?

offset = Tp(1) - 1LSB - DNL ( at code 1)

Please reply me ASAP.

hi  ywguo,

you are right that while calculating the DNL, offset is nullified as DNL = Tp[i+1] - Tp[i]. Now, here Tp[i+1] and Tp[i] are having same amount of offset. Therefore, while measuring DNL, offset is getting nullified.

But DNL is present at each and every code. Therefore, can I write Tp[1] = 1LSB width+DNL+Offset?

if this is true, then we need to consider the DNL value while considering the offset, else not. But, I am not sure whether, the above equation is right?