This paper presents the design of a low-power high-CMRR CMOS instrumentation amplifier (IA) aimed for biomedical applications. The amplifier fundamentals were initially presented followed by its main building blocks. Simulation and experimental results were presented and discussed. The IA circuit was designed in AMIS 1.5 µm technology and manufactured through the MOSIS Service. The measured gain,CMRR and power consumption were 65dB, 120dB and 100uW respectively

An instrumentation amplifier based on constant gm, rail-to-rail transconductance amplifiers is presented. The circuit was designed to 0.5,um AMIS C5 CMOS technology. Simulation results show that a -3dB bandwidth about 190 kHz could be obtained. Operating with a 3V supply and its dc gain set to 66 dB, the amplifier has a power consumption of 110,uW, and a CMRR higher than 140dB.I.

This paper presents the results from an investigation on the implementation of Current Mode Instrumentation Amplifiers (CMIAs) with rail-to-rail operational amplifiers (op amp) with a gm control circuit. The objective of employing rail-to-rail op amps in the implementation of a CMIA is the improvement of the common-mode operation range. The enhancement of the input common mode range (ICMR) is obtained using op amps with a rail-to-rail input stage followed by a cascode-based output stage. A prototype of the CMIA was implemented in standard 0.6 lm XFAB CMOS technology. Test results showed that the CMIA common mode range was extended but with moderated CMRR. To minimize this issue the amplifier was re-designed and sent to fabrication. Simulations with the components variations included were performed and showed the enhancement of the CMRR can be expected.

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The objective of this paper is to discuss the advantages and drawbacks of using Trapezoidal Association of Transistors (TAT) in the implementation of a lowpower high-CMRR CMOS instrumentation amplifier (IA) aimed for biomedical applications. IAs are well suited for biomedical applications due to its high CMRR. For the sake of comparison, two versions of the circuit were designed, prototyped and characterized. The performance of a version with its current mirrors implemented with TAT, where supposedly higher CMRR could be achievable, is compared to another with single-transistor implementation of current mirrors in order to analyze the CMRR performance. The IA circuit was designed in AMIS 1.5 lm technology and manufactured through the MOSIS Service. In addition to the better performance attained by the classic implementation of the amplifier, with CMRR higher than 120 dB, this version of the IA consumed less than one third of the area from the TAT version. Comparison of both versions from same topology indicates no advantages of using TATs in the current mirrors of this type of IA.