A HIGH PERFORMANCE FULLY DIFFERENTIAL PURE CURRENT MODE OPERATIONAL AMPLIFIER AND ITS APPLICATIONS

• Main Authors: SEYED JAVAD AZHARI, LEILA SAFARI
• Format: Article
• Language: English
• Published: Taylor's University 2012-08-01
• Series: Journal of Engineering Science and Technology
• Subjects: Fully differential current operational amplifier; Wide band COA; High CMRR COA; Constant bandwidth voltage amplifier; Rm amplifier
• Online Access: http://jestec.taylors.edu.my/Vol%207%20Issue%204%20August%2012/Vol_7_4_471-486_LEILA%20SAFARI.pdf

In this paper a novel high performance all current-mode fully-differential (FD) Current mode Operational Amplifier (COA) in BIPOLAR technology is presented. The unique true current mode simple structure grants the proposed COA the largest yet reported unity gain frequency while providing low voltage low power operation. Benefiting from some novel ideas, it also exhibits high gain, high common mode rejection ratio (CMRR), high power supply rejection ratio (PSRR), high output impedance, low input impedance and most importantly high current drive capability. Its most important parameters are derived and its performance is proved by PSPICE simulations using 0.8 μm BICMOS process parameters at supply voltage of ±1.2V indicating the values of 82.4 dB,52.3º, 31.5 Ω, 31.78 MΩ, 179.2 dB, 2 mW and 698 MHz for gain, phase margin, input impedance, output impedance, CMRR, power and unity gain frequency respectively. Its CMRR also shows very high frequency of 2.64 GHz at zero dB. Its very high PSRR+/PSRR- of 182 dB/196 dB makes the proposed COA a highly suitable block in Mixed-Mode (SOC) chips. Most favourably it can deliver up to ±1.5 mA yielding a high current drive capability exceeding 25. To demonstrate the performance of the proposed COA, it is used to realize a constant bandwidth voltage amplifier and a high performance Rm amplifier.