Gain Calibration Technique for Increased Resolution in FRC Data Converters

A feedforward residue compensation (FRC) data converter combines the benefits of a Nyquist rate analog-to-digital converter (ADC) with an oversampled converter. In this brief, the authors introduce a digital calibration technique that allows the FRC architecture to provide high resolution at high input signal frequencies. A high-performance pipeline ADC is used as an auxiliary converter to measure the quantization effects of an oversampled primary converter in the FRC architecture. A practical ADC architecture using a digital gain error calibration technique produces a 15-bit 70-Msample/s converter with greater than 100-dB spurious-free dynamic range. Simulation results are used to validate the architecture and gain calibration technique.