A novel self-calibrating scheme for video-rate 2-step flash analog-to-digital converter

The authors present an online trimming technique and an error-code self-trimming algorithm for video rate 2-step flash analog-to-digital converters (ADCs). The self-calibrating scheme, combining a digital error correction process and the self-trimming algorithm, dynamically maintains the random offsets of the comparators well within ±0.6 LSB and counteracts the interstage gain error, while improving the design of a conventional 2-step ADC towards a higher speed, a smaller size, and a lower power dissipation. The technique is applicable to subranging ADCs of up to any accuracy. Results from simulation of a 10-bit ADC are given to illustrate the superior efficiency of the scheme and the simplicity of the corresponding circuitry