CMOS current amplifiers : speed versus nonlinearity

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Koli, Kimmo
dc.date.accessioned 2012-02-13T12:11:06Z
dc.date.available 2012-02-13T12:11:06Z
dc.date.issued 2000-11-13
dc.identifier.isbn 951-22-5213-9
dc.identifier.issn 1455-8440
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/2301
dc.description.abstract This work deals with analogue integrated circuit design using various types of current-mode amplifiers. These circuits are analysed and realised using modern CMOS integration technologies. The dynamic nonlinearities of these circuits are discussed in detail as in the literature only linear nonidealities and static nonlinearities are conventionally considered. For the most important open-loop current-mode amplifier, the second-generation current-conveyor (CCII), a macromodel is derived that, unlike other reported macromodels, can accurately predict the common-mode behaviour in differential applications. Similarly, this model is used to describe the nonidealities of several other current-mode amplifiers because similar circuit structures are common in such amplifiers. With modern low-voltage CMOS-technologies, the current-mode operational amplifier and the high-gain current-conveyor (CCII∞) perform better than open-loop current-amplifiers. Similarly, unlike with conventional voltage-mode operational amplifiers, the large-signal settling behaviour of these two amplifier types does not degrade as CMOS-processes are scaled down. In this work, two 1 MHz 3rd -order low-pass continuous-time filters are realised with a 1.2 μm CMOS-process. These filters use a differential CCII∞ with linearised, dynamically biased output stages resulting in performance superior to most OTA-C filter realisations reported. Similarly, two logarithmic amplifier chips are designed and fabricated. The first circuit, implemented with a 1.2 μm BiCMOS-process, uses again a CCII∞. This circuit uses a pn-junction as a logarithmic feedback element. With a CCII∞ the constant gain-bandwidth product, typical of voltage-mode operational amplifiers, is avoided resulting in a constant 1 MHz bandwidth with a 60 dB signal amplitude range. The second current-mode logarithmic amplifier, based on piece-wise linear approximation of the logarithmic function by a cascade of limiting current amplifier stages, is realised in a standard 1.2 μm CMOS-process. The limiting level in these current amplifiers is less sensitive to process variation than in limiting voltage amplifiers resulting in exceptionally low temperature dependency of the logarithmic output signal. Additionally, along with this logarithmic amplifier a new current peak detectoris developed. en
dc.format.extent 293
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Helsinki University of Technology en
dc.publisher Teknillinen korkeakoulu fi
dc.relation.ispartofseries Report / Helsinki University of Technology, Department of Electrical and Communications Engineering, Electronic Circuit Design Laboratory en
dc.relation.ispartofseries 30 en
dc.subject.other Electrical engineering en
dc.title CMOS current amplifiers : speed versus nonlinearity en
dc.type G4 Monografiaväitöskirja fi
dc.description.version reviewed en
dc.contributor.department Department of Electrical and Communications Engineering en
dc.contributor.department Sähkö- ja tietoliikennetekniikan osasto fi
dc.subject.keyword analogue integrated circuit en
dc.subject.keyword CMOS en
dc.subject.keyword current amplifier en
dc.subject.keyword current-mode en
dc.subject.keyword amplifier distortion en
dc.subject.keyword nonlinearity en
dc.subject.keyword continuous-time filter en
dc.subject.keyword logarithmic amplifier en
dc.identifier.urn urn:nbn:fi:tkk-002462
dc.type.dcmitype text en
dc.type.ontasot Väitöskirja (monografia) fi
dc.type.ontasot Doctoral dissertation (monograph) en
dc.contributor.lab Electronic Circuit Design Laboratory en
dc.contributor.lab Piiritekniikan laboratorio fi


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