The Quantitative Model Research For High-speed Interpolatd ADCs Design

High-speed ADC has been widely used in ultra wideband systems, hard disk drive read channel, wireless systems and radar systems. With the development of electronic products function, higher performance of ADC is required. To meet these requirements, ADC is developing towards low-power, high-resolution and high-speed, while also increasing the difficulty of designing high-speed ADC. In high-speed ADC design, even for experienced engineers, also requires a lot of repetitive simulation and optimization to try different structure and design parameters, to find a relatively optimized design. However, this traditional design methods is tedious, time-consuming and not enough scientific rigor. In order to solve the above problem, this article researches on structure, bandwidth and offset voltage of pre-amplifier array of high-speed ADC.Based on the existing quantitative models and researches aided high-speed ADC design, this article proposes a quantitative models of high-speed ADC, and further presents a auxiliary method for high-speed ADC design.This quantitative model applies to typical multi-stage pre-amplifier array with interpolation/averaging technique, A set of quiescent current equation of output nodes is presented to describe the static working state of pre-amplifier array, and a set of small-signal current equation is presented to describe the small-signal model of pre-amplifier array, the entire pre-amplifier array is approximately equivalent to a single-pole system. With the computer data fitting and iterative algorithm, for different design parameters, the gain and bandwidth of the pre-amplifier array can be calculated. Then combine the device mismatch parameters of different process library and small-signal model of pre-amplifier array,we can calculate the offset voltage of pre-amplifier array, and get a aided method for high-speed ADC design with the aid of computer.Firstly, this article briefly describes the research and theoretical basis of the quantitative model of high-speed ADC, then a detail analysis of the common high-speed ADC design difficulties and key technologies is presented, and the proposed quantitative model is derived, and elaborates the principles of aided design methods,application scope and the result of verification. At last,with Hspice simulation software,, simulate the single module and overall ADC system based on TSMC 65 nm process to check the result of verification circuit. The results show that the quantitative model and aided design method has a high accuracy and feasible in the actual high-speed ADC design.