Title :
A high-swing CMOS telescopic operational amplifier
Author :
Gulati, Kush ; Lee, Hae-Seung
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., MIT, Cambridge, MA, USA
fDate :
12/1/1998 12:00:00 AM
Abstract :
A high-swing, high-performance CMOS telescopic operational amplifier is described. The high swing of the op-amp is achieved by employing the tail and current source transistors in the deep linear region. The resulting degradation in differential gain, common-mode rejection ratio (CMRR), and other amplifier characteristics are compensated by applying regulated-cascode differential gain enhancement and a replica-tail feedback technique. A prototype of the op-amp has been built in a 0.81-μm CMOS process. Operating from a power supply of 3.3 V, it achieves a differential swing of ±2.15 V, a differential gain of 90 dB, unity-gain frequency of 90 MHz, and >50-dB CMRR. It is shown, analytically and through simulations, that the operational amplifier maintains its high CMRR even at high frequencies
Keywords :
CMOS analogue integrated circuits; feedback amplifiers; operational amplifiers; 0.8 micron; 3.3 V; 90 dB; CMOS telescopic operational amplifier; common mode rejection ratio; differential swing; regulated cascode differential gain enhancement; replica tail feedback; unity gain frequency; CMOS process; Degradation; Differential amplifiers; Feedback; Frequency; Gain; Operational amplifiers; Power supplies; Prototypes; Tail;
Journal_Title :
Solid-State Circuits, IEEE Journal of