Attenuation‐factor error shaping technique for split CDAC in SAR ADCs.

A shaping technique is proposed to remedy the attenuation‐factor error in the split capacitor‐digital‐to‐analogue converter (CDAC) of a successive‐approximation‐register (SAR) ADC. By feeding back the previous quantised value of the least significant bit part to the most significant bit part, the inaccurate attenuation‐factor error caused by mismatches and parasitic components is shaped to high frequency. The in‐band dynamic performance is significantly improved without any calibration. Simulation results show that the proposed attenuation‐factor shaping technique improves the spurious‐free‐dynamic‐range by 10 dB, whereas the number of capacitors increases only 1.2%. [ABSTRACT FROM AUTHOR]