CMRR-bandwidth extension technique for CMOS differential amplifiers

Ben-Esmael, Mohamed; Hart, B.L.; Hayatleh, K.; Lidgey, F.J.

doi:10.1016/j.aeue.2014.04.022

Cited by 8 publications

(4 citation statements)

References 5 publications

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“…The agreement between simulations and calculations in [10] were excellent. The amplifier in [5] shows a common-mode gain with a pole and a zero, and a CMRR that decreases about 20 dB/decade. Therefore, if the CMRR for differential circuits, integrated or not, decreases inside the -3 dB bandwidth of the differential gain, this means that the commonmode gain increases inside that frequency band, yet this gain cannot be deducted from the modulus of the CMRR, even if the frequency dependence of the differential gain is known in detail, so that its subtleties remain hidden to the user.…”

Section: Resultsmentioning

confidence: 99%

“…The consequence is that unless both voltages undergo identical processing before being subtracted, the final result will depend not only on their difference but also on their average value, termed common-mode voltage, vc. In circuits with differential input and single-ended output, the output voltage contributed by the input common-mode voltage is described by the so-called common-mode gain Gc and the ratio between the differential-mode gain Gd and Gc, termed Common-Mode Rejection Ratio (CMRR) [4], [5], is the most common parameter to describe the effect of vc because the circuit output can be written as…”

Section: Introductionmentioning

confidence: 99%

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Common mode response effects in differential measurements

Hornero

Casas

Areny

2021

AEU - International Journal of Electronics and Communications

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In differential measurements, before digitized, the signal is conditioned by a differential or fully differential circuit which output depends on both the differential-and commonmode input voltages. Differential signals carry the desired information but common-mode voltages are a nuisance and their contribution to the output signal becomes an interference which is usually evaluated from the ratio between the respective gains for the differential-and common-mode input voltages, Common-Mode Rejection Ratio (CMRR). Usually, only the modulus of the CMRR is specified for IC differential. In this paper we demonstrate that the common-mode response depends on component tolerance and can be band-pass with gain peaking and positive phase shifts inside differential signal passband. Tolerances as low as ±0.01% cannot prevent phase shifts close to +90º. The presence of positive phase shifts in the common-mode gain can be suspected whenever the modulus of the CMRR decreases for frequencies below the -3 dB bandwidth of the differential gain but cannot be appraised from that modulus alone. Surprisingly, a high CMRR at low frequencies can worsen that effect. Therefore, common-mode effects in differential circuits can be evaluated only from the separate description of the response to differential and commonmode inputs signals.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Common mode response effects in differential measurements

Hornero

Casas

Areny

2021

AEU - International Journal of Electronics and Communications

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“…The Common Mode Rejection Ratio (CMRR) [16,17] is a significant parameter for Op-Amp circuits which shows the ability of an Op-amp on Common mode signal or common mode noise rejection. The Op-Amps used for Buck converter current measurement are designed to measure DC currents with high frequency ripples and high frequency pulse currents.…”

Section: Analysis Of Effects In Common Mode Rejection Ratio Due To Ga...mentioning

confidence: 99%

Buck Converter Current Measurement Using Differential Amplifier

Rajeswari¹,

Manikandan²

2023

Intelligent Automation &Amp; Soft Computing

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“…shows proposed solution[8] to enhance the CMRR bandwidth. Additional externally biased transistor M 4 is incorporated into the circuit to compensate gate to drain capacitance of transistor M 3 and its drain is connected to M 3 Source.…”

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confidence: 99%

A High-Performance Skin Impedance Measurement Circuit for Biomedical Applications

Hayatleh

Zourob

Nagulapalli

et al. 2019

J CIRCUIT SYST COMP

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This paper describes a high-performance impedance measurement circuit for the application of skin impedance measurement in the early detection of skin cancer. A CMRR improvement technique has been adopted for OTAs to reduce the impact of high-frequency common mode interference. A modified three-OTA instrumentation amplifier (IA) has been proposed to help with the impedance measurement. Such systems offer a quick, noninvasive and painless procedure, thus having considerable advantages over the currently used approach, which is based upon the testing of a biopsy sample. The sensor has been implemented in 65[Formula: see text]nm CMOS technology and post-layout simulations confirm the theoretical claims we made and sensor exhibits sensitivity. Circuit consumes 45[Formula: see text]uW from 1.5[Formula: see text]V power supply. The circuit occupies 0.01954[Formula: see text]mm2 silicon area.

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CMRR-bandwidth extension technique for CMOS differential amplifiers

Cited by 8 publications

References 5 publications

Common mode response effects in differential measurements

Common mode response effects in differential measurements

Buck Converter Current Measurement Using Differential Amplifier

A High-Performance Skin Impedance Measurement Circuit for Biomedical Applications

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