Time-Interleaved Analog-to-Digital Conversion With Online Adaptive Equalization

Online adaptive equalization is proposed to calibrate channel mismatch errors in time-interleaved (TI) analog-to-digital converter (ADC) arrays with a linear reference path. Code-domain filters are shown to be effective in removing interchannel as well as intrachannel nonlinearity and mismatch errors, including offset, gain, and differential nonlinearity (DNL) and integral nonlinearity (INL) mismatches. An 8-bit, 600-MS/s, 0.13- μm CMOS prototype measured a signal-to-noise plus distortion ratio (SNDR) of 31.0/47.4 dB, a spurious-free dynamic range (SFDR) of 32.8/63.6 dB, a DNL of 1.30/0.30 LSBs, and an INL of 1.70/0.23 LSBs in lab testing without/with equalization, respectively.