SAR ADC Calibration

Discussion in 'Homework Help' started by tyc, Jul 27, 2012.

  1. tyc

    Thread Starter New Member

    Jul 27, 2012

    I am trying to design a SAR ADC with self-calibration. I have read lots of papers and books regarding the self-calibration. All of them have used an additional Ccal to add/subtract the voltage error caused by the mismatch of each bit.

    My confusion is: once you add this additional Ccal to the capacitor array, the binary weighted relationship is no longer valid. For example, for a 3-bit SAR ADC, we have 4C, 2C,C and C as the original array. By adding an additional Ccal to the array. The binary weighted relationship between bits is broken. Am I missing something?

    Please help.