Small-signal analysis of fully-differential closed-loop op-amp circuits with arbitrary external impedance elements

Cooley, John J.; Avestruz, Al-Thaddeus; Leeb, Steven B.

doi:10.1049/iet-cds.2010.0401

Cited by 2 publications

(3 citation statements)

References 12 publications

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“…where ω p1 < ω pd , ω zd < ω p3 . As anticipated, (10) and (12) show the presence of pole-zero doublet in overall amplifier's frequency response.…”

Section: Auxiliary Op-amp With Cross-coupled Capacitorsupporting

confidence: 69%

“…This implies that the quality of transient response in this case depends on the location of UGBW of auxiliary amplifier. However, from (10) and (12), it can be observed that the addition of PFC across the auxiliary amplifier gives a pole-zero doublet which strongly depends on the value of C U . The effect of C U on the magnitude of slow-settling component can be understood by calculating the relative error in the pole and zero doublet frequencies.…”

Section: Effect Of C U On the Transient Responsementioning

confidence: 99%

“…Since it is difficult to isolate the effect of various parameters in circuit, the behaviour and performance of such a complex op‐amp is difficult to evaluate in practise directly. Modelling of the amplifier is necessary to understand its small signal behaviour and derive a systematic approach to design a high‐performance amplifier [9, 10]. Flandre , et al [11] have presented a symbolic analysis of basic gain‐boosted operational transconductance amplifier (OTA) to describe the pole–zero doublet behaviour and derive a criteria for optimal settling time.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Systematic design approach for a gain boosted telescopic OTA with cross‐coupled capacitor

Joshi

Shrimali

Sharma

2017

IET Circuits, Devices & Systems

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A symbolic analysis is presented to study a gain-boosted telescopic operational transconductance amplifier (OTA) with cross-coupled capacitor (positive feedback) across an auxiliary op-amp. The effects of positive feedback capacitor (PFC) on the pole-zero doublet introduced by the auxiliary op-amp are explored using analytical techniques and simulations. A complete transfer function of the OTA with PFC across the auxiliary op-amp is derived and verified through circuit simulations. The results obtained from circuit simulation and modelled transfer function show good agreement with each other. Furthermore, the analytical expressions for the feedback capacitor in terms of pole-zero locations, unity gain bandwidth (UGBW) and phase margin (PM) are presented. It is shown that UGBW, PM and settling behaviour of the OTA can be tuned by the PFC. A systematic design approach to improve the PM and settling behaviour is discussed. On the basis of the theory presented, 17% improvement in 0.01% settling time is demonstrated.

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“…where ω p1 < ω pd , ω zd < ω p3 . As anticipated, (10) and (12) show the presence of pole-zero doublet in overall amplifier's frequency response.…”

Section: Auxiliary Op-amp With Cross-coupled Capacitorsupporting

confidence: 69%

Section: Effect Of C U On the Transient Responsementioning

confidence: 99%