A fully differential and tunable CMOS current mode opamp based on transimpedance-transconductance technique
03 Aug 1997-Vol. 1, pp 168-171
TL;DR: In this paper, a fully differential and tunable CMOS current opamp is described, which is based on a transimpedance-transconductance circuit technique, and the use of a tunable transconductance block results in a voltage-tunable current op amp.
Abstract: A fully differential and tunable CMOS current opamp is described in this paper. This opamp is based on a transimpedance-transconductance circuit technique. The use of a tunable transconductance block results in a voltage-tunable current op amp. Simulation results demonstrate a high-gain which can be tuned between 70 dB and 96 dB. A high gain-bandwidth product of 145 MHz has been achieved at power consumption of less than 0.5 mW and power supply voltage of /spl plusmn/1.5 V.
Citations
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TL;DR: In this paper, a new realization of the differential input balanced output current opamp is proposed, operating with ± 1.5 V supplies, based on the use of current inverters to sense the input currents while providing a very low input resistance, 23?.
Abstract: In this paper a new realization of the differential input balanced output current opamp is proposed, operating with ±1.5 V supplies. Its architecture is based on the use of current inverters to sense the input currents while providing a very low input resistance, 23 ?. The opamp provides a maximum output swing of 700 ?A, with an input offset current of 3.5 nA. The differential gain achieved is 65.5 dB, and the differential structure adopted in the design provided a high CMRR, 89.5 dB, the proposed circuit is compared to other realizations with single and differential inputs. The applications of the current opamp are exploited some new applications are presented such as: MOSFET-C integrators, full non-linearity cancellation for MOS transistors, and finally a digitally tuned current-mode variable gain amplifier, which has a gain tuning range of 25 dB with a 0.05 dB step.
24 citations
23 May 2005
TL;DR: A new programmable bandpass filter approach is presented, based on an array of fully differential transconductance circuits to control the filter parameters, which shows a lower power consumption and a wide frequency range.
Abstract: A new programmable bandpass filter approach is presented. It is based on an array of fully differential transconductance circuits to control the filter parameters. The signal path does not contain any switch and fine-tuning of the filter parameters is implemented using programmable capacitors. The filter circuit is based on a biquadratic topology and designed with CMOS 0.18 /spl mu/m technology. SpectreS simulation results show a power consumption less than 5.2 mW with a /spl plusmn/ 0.9 V power supply. In addition, a wide frequency range (10-126 MHz) is achieved. The quality factor can also be tuned from 0.1 to 10.6.
11 citations
Cites background from "A fully differential and tunable CM..."
...Transconductor blocks connected in parallel are activated and deactivated by controlling their power supply as it was done for a programmable current amplifier [9]....
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TL;DR: In this paper, the authors describe a CMOS building block dedicated to high performance mixed analog-digital circuits and systems, which consists of six MOS transistors realizing a new wideband and tunable transconductance.
Abstract: This paper describes a CMOS building block dedicated to high performance mixed analog-digital circuits and systems. The circuit consists of six MOS transistors realizing a new wideband and tunable transconductance. The theory of operation of this device is presented and the effects of transistor nonidealities on the global performances are investigated. Use of the proposed circuit to realize tunable functions (Gm-C filter and current opamp) is illustrated. HSPICE simulations show a wide tuning range of the transconductance value from 40 μS to 950 μS (500 μS) for ±2.5 V (±1.5 V) supply voltages. The transconductance value remains constant up to frequencies beyond 500 MHz. The bandpass filter built with few transconductance blocks and capacitances was simulated with ±2.5 V supply voltage, the center frequency is tunable in the range of 30 MHz to 110 MHz. However, the opamp, which is designed with a transresistance-transconductance architecture, was simulated with ±1.5 V supply voltage. The gain of the opamp can be tuned between 70 dB and 96 dB and high gain-bandwidth product of 145 MHz has been achieved at power consumption of less than 0.5 mW. Experimental results on a fabricated transconductor chip are provided.
9 citations
Patent•
18 Oct 2016TL;DR: In this paper, a dual feedback loop regulator with a first amplifier coupled to an output node of the regulator, and the output node further coupled to a first feedback path and a second feedback path of a second amplifier was discussed.
Abstract: Certain aspects of the present disclosure generally relate a dual feedback loop regulator. For example, the regulator may include a first amplifier having an output coupled to an output node of the regulator, the output node further coupled to a first feedback path and a second feedback path of the regulator. A first input of a second amplifier may be coupled to the first feedback path and a second input of the second amplifier may be coupled to a reference path. The regulator may also include a transconductance stage having a first transistor and a first current source, the first transistor and the current source coupled to the first feedback path and the second feedback path, and a transimpedance stage coupled to the transconductance stage and an input of the first amplifier.
8 citations
TL;DR: Results altogether prove both excellent quality and well resistance of the proposed COA against technology and fabrication non-idealities.
Abstract: In this paper a novel high-frequency fully differential pure current mode current operational amplifier (COA) is proposed that is, to the authors' knowledge, the first pure MOSFET Current Mode Logic (MCML) COA in the world, so far. Doing fully current mode signal processing and avoiding high impedance nodes in the signal path grant the proposed COA such outstanding properties as high current gain, broad bandwidth, and low voltage and low-power consumption. The principle operation of the block is discussed and its outstanding properties are verified by HSPICE simulations using TSMC $$0.18\,\upmu \hbox {m}$$0.18μm CMOS technology parameters. Pre-layout and Post-layout both plus Monte Carlo simulations are performed under supply voltages of $$\pm 0.75\,\hbox {V}$$±0.75V to investigate its robust performance at the presence of fabrication non-idealities. The pre-layout plus Monte Carlo results are as; 93 dB current gain, $$8.2\,\hbox {MHz}\,\, f_{-3\,\text {dB}}, 89^{\circ }$$8.2MHzf-3dB,89? phase margin, 137 dB CMRR, 13 $$\Omega $$Ω input impedance, $$89\,\hbox {M}\Omega $$89MΩ output impedance and 1.37 mW consumed power. Also post-layout plus Monte Carlo simulation results (that are generally believed to be as reliable and practical as are measuring ones) are extracted that favorably show(in abovementioned order of pre-layout) 88 dB current gain, $$6.9\,\hbox {MHz} f_{-3\text {db}} , 131^{\circ }$$6.9MHzf-3db,131? phase margin and 96 dB CMRR, $$22\,\Omega $$22Ω input impedance, $$33\,\hbox {M}\Omega $$33MΩ output impedance and only 1.43 mW consumed power. These results altogether prove both excellent quality and well resistance of the proposed COA against technology and fabrication non-idealities.
7 citations
Cites methods from "A fully differential and tunable CM..."
...This is why in Rm − GmCOAs, the unity gain bandwidth of the complete amplifier is so much less than the fT of individual transistors that cannot offer the frequency advantages expected from a current mode system....
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...Based on the application, the COAs are designed in two main structures: (1) single input differential output structure which is the adjoint version of conventional differential input single output VOA and (2) Fully differential structure that is the adjoint one of conventional fully differential VOA [13]....
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...35 R m − G m 10 9b a C al cu la te d, b di ff er en tp os iti ve (1 24 ) an d ne ga tiv e (1 09 ) in pu tr es is ta nc es However due to the simple structure of Rm − Gm approach and its simple frequency compensation procedure, to date it is widely used to design COAs....
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...Table 1 shows a summary of performance parameters of some reported COAs with Rm − Gm architecture....
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...Literature survey shows that the commonmethod for designing COAs is to cascade sufficient numbers of transresistance-transconductance (Rm − Gm) couples [1,2,5– 7,13,16,22]....
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References
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01 Jan 1993
TL;DR: This book discusses current-mode Circuits from a Translinear Viewpoint, as well as applications of current-copier circuits, and the future of Analogue Integrated Circuit Design.
Abstract: * Chapter 1: Introduction * Chapter 2: Current-mode Circuits From A Translinear Viewpoint: A Tutorial * Chapter 3: Current Conveyor Theory And Practice * Chapter 4: Universal Current-Mode Analogue Amplifiers * Chapter 5: High Frequency CMOS Transconductors * Chapter 6: Bipolar Current Mirrors * Chapter 7: Dynamic Current Mirrors * Chapter 8: Gallium Arsenide Analogue Integrated Circuit Design Techniques * Chapter 9: Continuous-Time Filters * Chapter 10: Continuous-time and Switched Capacitor Monolithic Filters Based on LCR Filter Simulation using Current and Charge Variables * Chapter 11: Switched-Current Filters * Chapter 12: Analog Interface Circuits For VLSI * Chapter 13: Current Mode A/D and D/A Converters * Chapter 14: Applications of current-copier circuits * Chapter 15: Integrated Current Conveyor * Chapter 16: Applying 'Current Feedback' to Voltage Amplifiers * Chapter 17: Neural Network Building Blocks for Analog MOS VLSI * Chapter 18: Future of Analogue Integrated Circuit Design
1,382 citations
01 Jul 1993
TL;DR: In this article, a fully differential-input, differential-output, current-mode operational amplifier (COA) is described, which utilizes three second-generation current conveyors (CCIIs) as the basic building blocks.
Abstract: A fully differential-input, differential-output, current-mode operational amplifier (COA) is described. The amplifier utilizes three second-generation current conveyors (CCIIs) as the basic building blocks. It can be configured to provide either a constant gain-bandwidth product in a fully balanced current-mode feedback amplifier or a constant bandwidth in a transimpedance feedback amplifier. The amplifier is found to have a gain-bandwidth product of 3 MHz, an offset current of 0.8 mu A (signal range +or-700 mu A), and a (theoretically) unlimited slew rate. The amplifier is realized in a standard CMOS 2.4- mu m process. >
117 citations
TL;DR: In this paper, a high-speed wideband amplifier using a transconductance-transimpedance circuit technique is presented, which results in more reliable performances than are typically obtained from designs using conventional pole zero, cancellation or peaking technique.
Abstract: A high-speed wideband amplifier using a transconductance-transimpedance circuit technique is presented. The proposed circuit configuration results in more reliable performances than are typically obtained from designs using conventional pole-zero, cancellation or peaking technique. With a 0.8 /spl mu/m, double poly, double metal, n-well CMOS technology and single 5-V power supply, the prelayout simulation of this amplifier shows a -3 dB frequency of 300 MHz with a voltage gain of 14 dB when the loading capacitance is 1.5 pF. >
42 citations
30 May 1994
TL;DR: A CMOS implementation of a high-gain current mode operational amplifier (op amp) with a single-ended input and a differential output with inherent potential for high speed, low voltage operation normally associated with current mode analog signal processing is described.
Abstract: A CMOS implementation of a high-gain current mode operational amplifier (op amp) with a single-ended input and a differential output is described. This configuration is the current mode counterpart of the traditional voltage mode op amp. In order to exploit the inherent potential for high speed, low voltage operation normally associated with current mode analog signal processing, the op amp has been designed to operate off a supply voltage of 1.5 V, and the signal path has been confined to N-channel transistors. With this design, a gain of 94 dB and a gain-bandwidth product of 65 MHz has been achieved at a power consumption of 30 /spl mu/W. >
29 citations
TL;DR: In this article, a current operational amplifier with differential input and differential output is described, which can be integrated into a monolithic amplifier in either CMOS or bipolar technology, and experimental results obtained from an implementation using standard operational amplifiers and current mirrors realized using transistor arrays are compared to the theoretical analysis.
Abstract: A current operational amplifier with differential input and differential output is described. The amplifier is based on the parallel connection of a CCII+ current conveyor and a CCII− current conveyor followed by a differential output transconductance gain stage. The performance of the amplifier is analysed and experimental results obtained from an implementation using standard operational amplifiers and current mirrors realized using transistor arrays are presented and compared to the theoretical analysis. It is concluded that the static small signal open loop gain and the frequency response matches the performance of conventional voltage operational amplifiers. The input offset and bias errors and the common mode rejection are shown to be strongly dependent on the matching accuracy of the current mirrors used in the conveyors. The proposed configuration can easily be integrated into a monolithic amplifier in either CMOS or bipolar technology.
25 citations
"A fully differential and tunable CM..." refers background in this paper
...[ 3 ],[4]. According to the block diagram of the proposed...
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