Simplified Simulation and Measurement of the Signal Transfer Function of a Continuous-Time Pipelined Analog-to-Digital Converter

The continuous-time pipeline (CTP) analog-to-digital converter is a power- and area-efficient realization of an anti-alias filter + ADC cascade. The signal transfer function (STF), which is the transfer function of the anti-alias filter, is an important property of the CTP ADC. It is conventionally characterized by exciting the ADC with multiple input sinusoids. We demonstrate that a single-tone excitation is enough to determine the STF of the CTP ADC over its useful frequency range. The theory is supported by measurement results from a three-stage CTP ADC designed in a 65 nm CMOS process. The converter, equivalent to a sixth-order anti-alias filter + ADC, achieves 70 dB SNDR in a 100MHz bandwidth while sampling at f(s)= 800 MHz.