Realization of a PVT-Independent Current-Mode CMOS Logarithmic Circuit

This paper presents the realization of a current-mode and wide-range logarithmic circuit. The circuit is based on the Taylor series expansion approximation of the logarithmic function and employs MOSFET operating in saturation. The proposed circuit is insensitive to process, voltage and temperature (PVT) variations. The post-layout simulation using CADENCE Virtuoso tools validates the proposed design functionality in 0.18 μm TSMC CMOS technology. The circuit is powered by a ±1.25 volt DC source with a normalized input range that can go from -1 to 2 and can be used in up to 2.8 MHz application.