Title :
Constant gm rail-to-rail CMOS input stage with improved linearity
Author :
Popa, Cosmin ; Mitrea, Octavian
Author_Institution :
Fac. of Electron. & Telecommun., Bucharest Politechnica Univ., Romania
Abstract :
The classic CMOS differential amplifier has a strong nonlinearity for large values of the input voltage amplitude, so important odd-order distortion will appear for a sinusoidal input voltage. This paper presents a new original technique to improve the linearity of a CMOS differential amplifier by canceling the third and the fifth terms of the Taylor series of the output current. In order to obtain an extended range of the input voltage, two complementary CMOS differential amplifiers are used to achieve a constant transconductance of the input stage for rail-to-rail common mode input voltage, a maximum current selecting circuit is added. SPICE simulation using MOSIS 0.8μ confirms the theoretical analysis
Keywords :
CMOS integrated circuits; SPICE; differential amplifiers; series (mathematics); CMOS input stage; MOSIS 0.8μ; SPICE simulation; Taylor series; amplifier nonlinearity; complementary amplifiers; constant transconductance; differential amplifier; input voltage; maximum current selecting circuit; output current; rail-to-rail common mode input voltage; Circuits; Differential amplifiers; Harmonic distortion; Impedance; Linearity; Operational amplifiers; Rails; Taylor series; Transconductance; Voltage;
Conference_Titel :
Image and Signal Processing and Analysis, 2001. ISPA 2001. Proceedings of the 2nd International Symposium on
Conference_Location :
Pula
Print_ISBN :
953-96769-4-0
DOI :
10.1109/ISPA.2001.938683
