Behavioral non-ideal Model of 8-bit Current-Mode Successive Approximation Registers ADC by using Simulink

Abstract

In this paper a new non-ideal model of 8-bit Current Mode Successive Approximation Analog-Digital Converter (CM-SAR-ADC) has been proposed, the main blocks of CM SAR ADC are a current sample and hold, a current comparator, SAR logic register and current steering digital to analogue converter (DAC). The model is implemented in Matlab Simulink environment with non ideals factors such as switching noise, clock feed through, charge injection, flicker noise, clock jitter, settling error, and the effect of MOS transistor mismatch in the current sample and hold(S/H) and in the current steering DAC models, the delay time and the current offset are introduced as non-ideal sources to the current comparator model. The comparisons of the simulation results using 8-bits CM SAR ADC with ideal and non-ideal models confirmed the effects of the non ideality sources on the parameters of the ADC.