Spectral Impact of Mismatches in Interleaved ADCs

TL;DR

This paper derives exact expressions to quantify how offset, gain, and timing mismatches in interleaved ADCs affect their output spectrum, aiding calibration and yield optimization.

Contribution

It introduces compact formulas for the spectral impact of mismatches and demonstrates their use in calibration and yield analysis for interleaved ADCs.

Findings

Derived exact expressions for mismatch-induced spectral spurs.

Provided a method to determine calibration step sizes based on yield constraints.

Enabled improved calibration strategies for high-speed ADC arrays.

Abstract

Interleaved ADCs are critical for applications requiring multi-gigasample per second (GS/s) rates, but their performance is often limited by offset, gain, and timing skew mismatches across the sub-ADCs. We propose exact but compact expressions that describe the impact of each of those non-idealities on the output spectrum. We derive the distribution of the power of the induced spurs and replicas, critical for yield-oriented derivation of sub-ADC specifications. Finally, we provide a practical example in which calibration step sizes are derived under the constraint of a target production yield.