Design of a High Performance, Low Power, Fully Differential Telescopic Cascode Amplifier using Common-Mode Feedback Circuit

Abstract

This paper describes the design of a high performance, low power fully differential telescopic amplifier. As is well known, high gain differential amplifiers require an additional Common-Mode Feedback (CMFB) circuit owing to their high output impedances. This is because high output impedance makes it difficult to fix their output DC level. The additional CMFB circuitry serves the function of controlling the output common mode DC level. The telescopic amplifier designed here using CMFB circuitry is simulated using 180 nm technology in Cadence EDA tool. A low frequency gain of 63.9dB is obtained with a power dissipation of 1.38mW and a Unity Gain Frequency of 114 MHz.