A new structure of substage in pipelined analog-to-digital converters

The article presents a new (1+1)-bit/stage structure for pipelined analog-to-digital converters (ADC). When the input analog signal of the structure exceeds the converting range of the whole ADC, the signal can still be converted precisely and the output residue voltage of the structure will be in the converting range of the ADC. The structure is used in a 12-bit 40 MS/s pipelined ADC to test its function. The testing results show that the structure has right function and can correct the transition error induced by offset of comparators' decision levels. The ADC implemented in Semiconductor Manufactory International Corporation (SMIC) 0.18 μm CMOS process consumes 210 mW and occupies a chip area of 3.2×3.7 mm2.