Impedance-mode capacitance multiplier with OTA-based flipped voltage follower for high accuracy and large multiplication factor

Abstract

A capacitance multiplier with large multiplication factor, increased accuracy, and class AB operation is presented. The multiplier is an impedance mode implementation consisting of a Flipped Voltage Follower based on Operational Transconductance Amplifiers (OTA). This gives the possibility to offer rail-to-rail operation and class AB operation to drive demanding loads depending on the application. In addition, one of the OTAs is designed to offer a transconductance gain based on passive resistors and achieve increased accuracy in the multiplication factor by means of proper layout techniques. The circuit was implemented in a 0.5µm technology and has multiplication factors of 10, 100, 1k and 10k, a power dissipation of 0.56mW and a silicon area of 0.059mm2. Simulation and experimental results of the multiplier demonstrate the proper operation.