A 8-bit 150MHz low-power CMOS folding and interpolating analog-to-digital converter with a fully-folding technique is designed in a 0.35µm standard digital CMOS process. Folding circuits are not only used in fine converter but also in coarse one and in bit synchronization block to reduce the number of comparators for low power. A novel bit synchronization architecture based on folding circuits is presented. A low-power encoder using a novel arithmetic is adopted. The total power dissipation is merely 65mW at a 3.3V supply.