We are currently selecting precision DAC chips, AD5760/80/90 (16/18/20 bits) are pin-compatible, while AD5781/91 (18/20 bits) is another line. Our product is aiming to support a A-16 bit, B-18 bit, C-20 bit versions, however, we prefer the ultimate performance of AD5791 but the AD5760/80/90 are pin-compatible, which means that one design may fit them all. We would like to know what is the major differences (beside footprint) of these two chips?