Design and implementation of 0.8-V Active RC polyphase filter using 0.18-µm CMOS inverters with resistive level shifter

A CMOS inverter based amplifier operable down to 0.8 V of power supply has been proposed. The CMOS inverter amplifier has a level shifter circuit at its input to effectively reduce its threshold voltages. The level shift is realized by feeding an input signal via a resistive voltage divider which is connected between VDD and GND. The proposed amplifiers are used to construct a three-stage active RC polyphase filter with 0.3 to 3 MHz passband. The active RC polyphase filter was fabricated in 0.18 mum CMOS technology, and measured results show that the proposed amplifier successfully operates from 0.8 V supply voltage.