A gm/ID based methodology for the design ofCMOS analog circuits and its application to the synthesis of asilicon-on-insulator micropower OTA

A new design methodology based on a unified treatment of all the regions of operation of the MOS transistor is proposed. It is intended for the design of CMOS analog circuits and especially suited for low power circuits where the moderate inversion region often is used because it provides a good compromise between speed and power consumption. The synthesis procedure is based on the relation between the ratio of the transconductance over DC drain current g_m/I_D and the normalized current I_D/(W/L). The g_m/I_D indeed is a universal characteristic of all the transistors belonging to a same process. It may be derived from experimental measurements and fitted with simple analytical models. The method was applied successfully to the design of a silicon-on-insulator (SOI) micropower operational transconductance amplifier (OTA)