Analog CMOS/SOI with NMOS-SOI-depletion transistors

Summary form only given. Improved analog/SOI A/D converter and opamp performance results were obtained by adding normally-on NMOS-depletion transistors to a standard CMOS/SOS process. The improvement results in part from the low RC time constant substrate tie associated with the structure. Dynamic control of substrate potential (a component of threshold voltage) is important for high-speed processing of millivolt level analog signals. Other advantages are: (1) reduced voltage drop across depletion transistors, allowing wider signal swing and/or reduced operating voltage; (2) higher currents from small, lower-capacitance transistors; (3) superior gain characteristics in saturation; and (4) new circuit options possible with N-depletion transistors