Finding all elementary circuits exploiting transconductance

Abstract

Commonly used elementary circuits like single-transistor amplifier stages, the differential pair, and current mirrors basically exploit the transconductance property of transistors. This paper aims at finding all elementary transconductance-based circuits. For this purpose, all graphs of two-port circuits with one or two voltage controlled current sources are generated systematically. This results in 150 graphs of "finite transactance two-port circuits" with at least one nonzero transmission parameter. Each of them can be implemented in various ways using transistors and resistors, covering many commonly required types of two-ports. To illustrate the usefulness of the technique several alternative circuit implementations for current amplifiers and voltage followers are generated. A new wide-band low-noise amplifier generated with the technique was realized in 0.35-/spl mu/m CMOS.