A generator of trapezoidal association of transistors (TAT): improving analog circuits in a pre-diffused transistor array

This paper presents the Trapezoidal Association of Transistors Generator (TATGen) tool, targeted to mixed analog-digital design on the PROCIMS Sea-of-Transistors (SoT) array (1996), in 1.0 /spl mu/m CMOS digital technology (single poly, 2 metal layers). The focus is mainly in the generator, its characteristics, functionality and related details. The TATGen, based on (1994), runs an algorithm specially designed for this purpose in order to build an equivalent composite transistor, which provides good performance of analog circuits on the digital pre-diffused structure. Some analog circuits designed and fabricated in both methodology (SoT and full-custom) are presented for fair comparisons. Layouts obtained with TATGen are briefly shown, and limitations of TATs are also discussed.