Analysis of Integral Nonlinearity in Radix-4 Pipelined Analog-to-Digital Converters

In this paper an analytic approach to estimate the nonlinearity of radix-4 pipelined analog-to-digital converters due to the circuit non-idealities is presented. Output voltage of each stage is modeled as sum of the ideal output voltage and non-ideal output voltage (error voltage), in which non-ideal output voltage is created by capacitor mismatch, comparator offset, input offset, and finite gain of amplifier. The integral nonlinearity (INL) can be obtained as the expected value of total input error due to the errors in all stages of radix-4 pipelined ADC.