A New High-Gain Operational Amplifier Using Transconductance-Enhancement Topology Integrated With Metal Oxide TFTs

Chen, Zhuojia; Xu, Wen-Xing; Wu, Jiandong; Zhou, Lei; Wu, Weijing; Zou, Jianhua; Wang, Lei; Liu, Yurong; Peng, Junbiao

doi:10.1109/jeds.2018.2883585

Cited by 18 publications

(7 citation statements)

References 15 publications

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“…A phase margin of 67° is reported with this work which ensures the stability of the circuit. From the frequency response of the circuit, unity gain frequency (

f_{ug}

) of 215 kHz is reported which is higher than [9, 22–24]. However, a higher value of

f_{ug}

is reported in [8, 11] due to advancement in technology and fabrication process.…”

Section: Resultsmentioning

confidence: 99%

High gain operational amplifier and a comparator with a‐IGZO TFTs

Sharma

Bahubalindruni

Bharti

et al. 2020

IET Circuits, Devices & Systems

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This study presents a novel high gain operational amplifier (op-amp) and a comparator using n-type all enhancement amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs). The proposed op-amp employs regulated cascode topology in conjunction with capacitive bootstrap load, which enhances the gain to 159.87% (V/V) as compared to op-amp with bootstrapping load. In addition, common mode feedback is introduced in the circuit which improves the common-mode rejection ratio (CMRR) of the amplifier without hampering the output voltage swing. The proposed op-amp offers a voltage gain of 46.2 dB, phase margin of 67°, CMRR of 51.8 dB, unity gain frequency of 215 kHz and power consumption of 0.22 mW. Furthermore, a novel comparator circuit at a clock frequency of 50 kHz is reported. The power consumption of the circuit is 0.248 mW and it can discriminate a minimum voltage of 50 mV. The performance of the proposed circuits is demonstrated using an analytical model of a-IGZO in Cadence environment with a channel length of 20 µm at a supply voltage of 10 V. Further with the help of the circuits reported in this work, many sensing systems of practical importance can be developed, such as smart packaging and bio-medical wearable devices using flexible electronics.

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“…A phase margin of 67° is reported with this work which ensures the stability of the circuit. From the frequency response of the circuit, unity gain frequency (

f_{ug}

) of 215 kHz is reported which is higher than [9, 22–24]. However, a higher value of

f_{ug}

is reported in [8, 11] due to advancement in technology and fabrication process.…”

Section: Resultsmentioning

confidence: 99%

High gain operational amplifier and a comparator with a‐IGZO TFTs

Sharma

Bahubalindruni

Bharti

et al. 2020

IET Circuits, Devices & Systems

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“…The pseudo-PMOS load is shown to be inherently stable despite of having internal positive-feedback loop following the aforementioned condition. Additionally, positive-feedback techniques can also be deployed to boost the transconductance g m itself [10], [11], thus resulting in higher performance. However, in this report we focus on realization of high output impedance with such technique.…”

Section: Introductionmentioning

confidence: 99%

Positive-Feedback-Based Design Technique for Inherently Stable Active Load Toward High-Gain Amplifiers With Unipolar a-IGZO TFT Devices

Dandekar

Myny

Dehaene

2022

IEEE Solid-State Circuits Lett.

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This letter presents analysis of an inherently stable positive-feedback based active load, first reported in our prior work, to realize high gain analog amplifiers using unipolar a-IGZO TFT technology. Additionally reported are theoretical performance bounds and design guidelines to maximally utilize a general positive-feedback scheme for the active load while maintaining stability. To demonstrate a design implementation, a single stage fully differential operational transconductance amplifier with common mode feedback has been manufactured and measured to have 40 dB open-loop gain at DC and a unity gain frequency of 61 kHz while driving a 30 pF load capacitance.

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“…Since most IGZO TFTs operate in the enhancement mode with

V_{th} bold-italic> bold0

V, the “pseudo‐E” variety has been more popularly deployed 13 . However, there are costs associated with the implementation of the pseudo‐CMOS design methodology, including larger circuit footprint, limited gain 14,15 and reduced circuit speed.…”

Section: Introductionmentioning

confidence: 99%

Low‐temperature elevated‐metal metal‐oxide thin‐film transistors and circuit building blocks on a flexible substrate

et al. 2022

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A low‐temperature (300°C) thin‐film transistor (TFT) technology based on the elevated‐metal metal‐oxide device architecture has been developed and deployed for realizing basic circuit building blocks on a polyimide (PI) flexible substrate. Both digital and analog circuit blocks have been simulated, fabricated, and characterized. Exhibiting insignificant impact on the performance of the TFTs, a 308‐nm excimer laser was used to lift‐off the PI from its glass‐carrier substrate. Based on a multi‐“threshold voltage” technology allowing both depletion‐ and enhancement‐mode TFTs, alternative area‐saving, ratio‐less building blocks have been designed and simulated. The required tuning of the threshold voltage could be accomplished by selective fluorination, laser annealing, incorporation of multiple semiconducting metal oxides, or deployment of a dual‐gate architecture.

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A New High-Gain Operational Amplifier Using Transconductance-Enhancement Topology Integrated With Metal Oxide TFTs

Cited by 18 publications

References 15 publications

High gain operational amplifier and a comparator with a‐IGZO TFTs

High gain operational amplifier and a comparator with a‐IGZO TFTs

Positive-Feedback-Based Design Technique for Inherently Stable Active Load Toward High-Gain Amplifiers With Unipolar a-IGZO TFT Devices

Low‐temperature elevated‐metal metal‐oxide thin‐film transistors and circuit building blocks on a flexible substrate

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