A 0.3-V 98-dB Rail-to-Rail OTA in $0.18~\mu$ m CMOS

Kulej, Tomasz; Khateb, Fabian

doi:10.1109/access.2020.2972067

Cited by 66 publications

(42 citation statements)

References 21 publications

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“…Inverter-based OTA topologies [11,12] and their respective ULV variations [13,14] have been proposed, as well as push-pull-based, bulk-driven OTAs [15][16][17][18]. An improved single-ended OTA has been proposed in [19], exploiting the properties of improved composite transistors [20] into a variation of the bulk Nauta inverter-based OTA [21].…”

Section: Introductionmentioning

confidence: 99%

Self-Biased and Supply-Voltage Scalable Inverter-Based Operational Transconductance Amplifier with Improved Composite Transistors

2021

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This paper deals with a single-stage single-ended inverter-based Operational Transconductance Amplifiers (OTA) with improved composite transistors for ultra-low-voltage supplies, while maintaining a small-area, high power-efficiency and low output signal distortion. The improved composite transistor is a combination of the conventional composite transistor and forward-body-biasing to further increase voltage gain. The impact of the proposed technique on performance is demonstrated through post-layout simulations referring to the TSMC 180 nm technology process. The proposed OTA achieves 54 dB differential voltage gain, 210 Hz gain–bandwidth product for a 10 pF capacitive load, with a power consumption of 273 pW with a 0.3 V power supply, and occupies an area of 1026 μm2. For a 0.6 V voltage supply, the proposed OTA improves its voltage gain to 73 dB, and achieves a 15 kHz gain–bandwidth product with a power consumption of 41 nW.

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Section: Introductionmentioning

confidence: 99%

Self-Biased and Supply-Voltage Scalable Inverter-Based Operational Transconductance Amplifier with Improved Composite Transistors

2021

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“…The bulk-driven technique [29][30][31] allows rail-to-rail ICMR in ULV amplifiers at the cost of reduced gain and a resistive input impedance component. Bulk-driven amplifiers are surely one of the best alternatives to attain rail-to-rail input-output swing when a well-defined bias or common mode current is required to increase the robustness against process, supply voltage, and temperature (PVT) variations [32][33][34][35][36][37][38][39][40][41][42]. Indeed, the signal-free gate terminals can be used to accurately set the bias current of the different OTA stages.…”

Section: Introductionmentioning

confidence: 99%

A Tree-Based Architecture for High-Performance Ultra-Low-Voltage Amplifiers

Centurelli

Sala

Monsurrò

et al. 2022

JLPEA

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In this paper, we introduce a novel tree-based architecture which allows the implementation of Ultra-Low-Voltage (ULV) amplifiers. The architecture exploits a body-driven input stage to guarantee a rail-to-rail input common mode range and body-diode loading to avoid Miller compensation, thanks to the absence of high-impedance internal nodes. The tree-based structure improves the CMRR of the proposed amplifier with respect to the conventional OTA architectures and allows achievement of a reasonable CMRR even at supply voltages as low as 0.3 V and without tail current generators which cannot be used in ULV circuits. The bias currents and the static output voltages of all the stages implementing the architecture are accurately set through the gate terminals of biasing transistors in order to guarantee good robustness against PVT variations. The proposed architecture and the implementing stages are investigated from an analytical point of view and design equations for the main performance metrics are presented to provide insight into circuit behavior. A 0.3 V supply voltage, subthreshold, ultra-low-power (ULP) OTA, based on the proposed tree-based architecture, was designed in a commercial 130 nm CMOS process. Simulation results show a dc gain higher than 52 dB with a gain-bandwidth product of about 35 kHz and reasonable values of CMRR and PSRR, even at such low supply voltages and considering mismatches. The power consumption is as low as 21.89 nW and state-of-the-art small-signal and large-signal FoMs are achieved. Extensive parametric and Monte Carlo simulations show the robustness of the proposed circuit to PVT variations and mismatch. These results confirm that the proposed OTA is a good candidate to implement ULV, ULP, high performance analog building blocks for directly harvested IoT nodes.

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“…nF-range), making their Frequency Compensation Techniques (FCTs) unsuitable to be systematically expanded to higher stages or for driving small loads. All other conventional FCTs in the literature are only suitable for 2-and 3-stage OTAs as in [7][8][9], and are all based on limiting the frequency range of operation in order to ensure stability when configurated in closed loop.…”

Section: Introductionmentioning

confidence: 99%

A Scalable Many-Stage CMOS OTA for Closed-Loop Applications

Mohammed

Roberts

2021

2021 IEEE International Symposium on Circuits and Systems (ISCAS)

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In this work, a new scalable CMOS OTA design that systematically enables cascading many identical OTA stages is proposed. This scalable design of the many-stage OTA ensures stability, when configurated in closed loop, by means of a new scalable frequency compensation technique. The presented design realizes a CMOS OTA with scalable-gain that increases in 25 dB increments per stage, achieving a total gain from 50 dB to 150 dB for a 2-stage to a 6-stage OTA, respectively. Stability of the many-stage OTA is ensured by re-positioning the poles and zeros of all gain stages in a systematic scalable pattern whenever a new gain-stage is added. The presented design was based on a TSMC 65 nm CMOS process.

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A 0.3-V 98-dB Rail-to-Rail OTA in $0.18~\mu$ m CMOS

Cited by 66 publications

References 21 publications

Self-Biased and Supply-Voltage Scalable Inverter-Based Operational Transconductance Amplifier with Improved Composite Transistors

Self-Biased and Supply-Voltage Scalable Inverter-Based Operational Transconductance Amplifier with Improved Composite Transistors

A Tree-Based Architecture for High-Performance Ultra-Low-Voltage Amplifiers

A Scalable Many-Stage CMOS OTA for Closed-Loop Applications

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