Design of an integrated tunable differential negative resistance in UMC 0.18 μm

A voltage tunable CMOS differential active resistor and its application

“…Negative resistors have a diverse and wide range of applications including enhancing the gain-bandwidth product of amplifiers, 1 improving the conversion gain of mixers, 2,3 realizing active inductors with improved performance, 4 network tuners 5 , filter design, 6 and most importantly the realization of sinusoidal as well as relaxation oscillators. [7][8][9] Differential resistors are particularly important as they can realize both grounded or floating resistors and many designs have been proposed using MOS transistors 10,11 as well as other types of transistors. Differential negative resistors are of two main types: passive and active.…”

“…On the other hand, active differential negative resistors offer the possibility of electronic tunability either through a biasing voltage source or through a biasing current source. However, extending their dynamic range usually results in a complex circuit design with many transistors such as the 15 transistor positive/negative resistor circuit reported in Tantry et al 16 and Oura et al 17 or the 8 transistor one recently reported in Richelli et al 11 requiring four PMOS and four NMOS transistors. The simplest possible differential active negative resistor remains to be the classical voltage-controlled cross-coupled transistor pair, 18 which can be realized using BJT or MOS transistors of both types.…”