A 69.5 mW 20 GS/s 6b Time-Interleaved ADC With Embedded Time-to-Digital Calibration in 32 nm CMOS SOI

Abstract

A 20 GS/s 6b time-interleaved ADC is implemented in 32 nm CMOS SOI with an embedded time-to-digital converter to sense timing skew, and the randomness of process mismatch is exploited to compensate for the clock misalignment and dynamic offset errors of comparators that occur during high-speed operation. To achieve low-power consumption at high-speed operation with small-size transistors, a low-complexity on-chip calibration reduces gain, offset, and delay mismatches in background. With the timing skew calibration, the spurs due to clock misalignment are reduced by 20 dB. The proposed ADC achieves an SNDR of 30.7 dB at Nyquist frequency and consumes only 69.5 mW with a figure-of-merit of 124 J/conv-step.