A 2 GHz effective sampling frequency K-Delta-1-Sigma analog-to-digital converter

As CMOS technology scales to nanometer dimensions, analog-to-digital converter (ADC) design has become increasingly more challenging. This is mainly due to the increased transistor leakage currents, process variations, and poor matching. The K-Delta-1-Sigma (KD1S) modulator was proposed as a practical solution for designing high-speed ADCs in nanometer CMOS processes. This paper presents an 8-path KD1S modulator with an effective sampling frequency of 2 GHz derived from a 250 MHz input clock. The simulation results confirm the true first-order noise shaping of the modulator. The simulated SNR is 44.95 dB and the simulated SNDR is 44.41 dB corresponding to N_eff = 7.17 bits with a conversion bandwidth of 15.625 MHz.