Analysis and Cancellation of Crosstalk in Multi-Channel Pipelined-SAR ADCs

This paper presents a detailed analysis of the crosstalk that occurred in multi-channel pipelined-successive approximation register (pipelined-SAR) analog-to-digital converters (ADCs). According to the circuit model simulation results, the capacitive crosstalk dominates while inductive crosstalk is negligible. The different paths of crosstalk are analyzed and their influences are compared. The result shows that most crosstalk will transform into noise in the output, degrading the signal-to-noise ratio (SNR) performance of the ADC. And some specific types of digital outputs can generate large harmonics that affect spurious-free dynamic range (SFDR) performance. Furthermore, an adaptive-filter-based cancellation method is proposed for input coupled crosstalk. The method is validated in the test of a 16-channel 14-bit 50-MS/s ADC, and the measurement results show that crosstalk is effectively eliminated.