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Activefeedback frequencycompensation technique for lowpower multistage amplifiers
 IEEE J. SolidState Circuits
, 2003
"... technique for lowpower operational amplifiers is presented in this paper. With an activefeedback mechanism, a highspeed block separates the lowfrequency highgain path and highfrequency signal path such that high gain and wide bandwidth can be achieved simultaneously in the AFFC amplifier. The ..."
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Cited by 7 (3 self)
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technique for lowpower operational amplifiers is presented in this paper. With an activefeedback mechanism, a highspeed block separates the lowfrequency highgain path and highfrequency signal path such that high gain and wide bandwidth can be achieved simultaneously in the AFFC amplifier. The gain stage in the activefeedback network also reduces the size of the compensation capacitors such that the overall chip area of the amplifier becomes smaller and the slew rate is improved. Furthermore, the presence of a lefthalfplane zero in the proposed AFFC topology improves the stability and settling behavior of the amplifier. Threestage amplifiers based on AFFC and nestedMiller compensation (NMC) techniques have been implemented by a commercial 0.8 m CMOS process. When driving a 120pF capacitive load, the AFFC amplifier achieves over 100dB dc gain, 4.5MHz gainbandwidth product (GBW) , 65 phase margin, and 1.5V / s average slew rate, while only dissipating 400 W power at a 2V supply. Compared to a threestage NMC amplifier, the proposed AFFC amplifier provides improvement in both the GBW and slew rate by 11 times and reduces the chip area by 2.3 times without significant increase in the power consumption. Index Terms—Active feedback, activecapacitivefeedback network, amplifiers, frequency compensation, multistage amplifiers.
A dualpath bandwidth extension amplifier topology with dualloop parallel compensation
 IEEE J. SolidState Circuits
, 2003
"... Abstract—A dualpath amplifier topology with dualloop parallel compensation technique is proposed for lowpower threestage amplifiers. By using two parallel highspeed paths for highfrequency signal propagation, there is no passive capacitive feedback network loaded at the amplifier output. Both ..."
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Cited by 2 (1 self)
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Abstract—A dualpath amplifier topology with dualloop parallel compensation technique is proposed for lowpower threestage amplifiers. By using two parallel highspeed paths for highfrequency signal propagation, there is no passive capacitive feedback network loaded at the amplifier output. Both the bandwidth and slew rate are thus significantly improved. Implemented in a 0.6 m CMOS process, the proposed threestage amplifier has over 100dB gain, 7MHz gainbandwidth product, and 3.3V / s average slew rate while only dissipating 330 W at 1.5 V, when driving a 25k //120pF load. The proposed amplifier achieves at least two times improvement in bandwidthtopower and slewratetopower efficiencies than all other reported multistage amplifiers using different compensation topologies. Index Terms—Amplifiers, dual loop, dual path, frequency compensation, multistage amplifiers. I.
Slew Rate
, 2009
"... specifications. Use the one equation all region transistor model. Provide tables summarizing results and significant plots. Do not use CADENCE circuits figures in your report; draw your own (clean) circuit figures. Discuss the main results. ..."
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specifications. Use the one equation all region transistor model. Provide tables summarizing results and significant plots. Do not use CADENCE circuits figures in your report; draw your own (clean) circuit figures. Discuss the main results.
Gain Bandwidth Product>2.85 DC Gain Phase Margin Settling Time
"... To obtain the slope factor, first we need to determine the normalizing current of the ACM model. The circuit used is showing in the figure below. Schematic Setup for the Extraction of Is The transistors are biased to be in the saturation region. A current with a small delta value is applied to each ..."
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To obtain the slope factor, first we need to determine the normalizing current of the ACM model. The circuit used is showing in the figure below. Schematic Setup for the Extraction of Is The transistors are biased to be in the saturation region. A current with a small delta value is applied to each transistor and the corresponding change in source voltage of the transistors is measured. The normalization current (Is) is then computed as follows. Plot showing delta Vs used for Extraction of IsThe following parameters were used: From the simulation V V Substituting these values into equation 1 gives A Next, the Vp parameter has to also be determined. From the ACM model It is observed that with id = 3, Vp =Vs. Fig 2.4 is the setup for obtaining Vp and Fig 2.5 is the result from the dc sweep of the setup. A current of 3Is is used. Setup used for Obtaining Vp With this parameter, the value of “n ” can now be obtained. By ACM model definition, n is the derivative of Vg with respect to Vp. From the previous simulation, Vp = Vs.Plot of n vs Vp for NMOS and PMOS From the plot the value of n is extracted at Vg = 0 for NMOS and Vg = Vdd = 3 for PMOS be obtained.
Texas A&M University ECEN 607 Advanced Analog Circuit Design Homework 1
, 2009
"... Typically, when a dc gain of close to 80 dB or more is required from a multistage amplifier with simple, nancascode gain stages, people resort to using either 3 stage or 4 stage amplifiers. Any more than that would make the design very complex since there will be so many variables to so deal with. E ..."
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Typically, when a dc gain of close to 80 dB or more is required from a multistage amplifier with simple, nancascode gain stages, people resort to using either 3 stage or 4 stage amplifiers. Any more than that would make the design very complex since there will be so many variables to so deal with. Even for the four stage amplifier, there is a relative difficulty because of the large number of variables required to optimize the design. Previous results from published works on NGCC amplifiers prove that both 3 and 4 stage amplifiers can attain very high dc gain with enough phase margins and good settling time. The 3 stage is likely to consume less power but at the cost of a very strict design to ensure that all the specifications are met, but makes stabilizing the amplifier easier. The 4 – stage although a little more complex, provides a little more freedom, relaxing a bit the design constraints for each stage while still achieving the desired specs. It is more difficult to stabilize the amplifier in this case. Determination of Slope Factor “n” To obtain the slope factor, first we need to determine the normalizing current of the ACM model. The circuit used is showing in the figure below. (a) PMOS (b) NMOS Schematic Setup for the Extraction of Is The transistors are biased to be in the saturation region. A current with a small delta value is applied to each transistor and the corresponding change in source voltage of the transistors is measured. The normalization current (Is) is then computed as follows. For NMOS:
Slew Rate
, 2013
"... Design a NGCC Amplifier with a differential input in 0.5�m CMOS technology for the following specifications Use the one equation all region transistor model. Provide tables summarizing results and significant plots. Do not use CADENCE circuits figures in your report; draw your own (clean) circuit fi ..."
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Design a NGCC Amplifier with a differential input in 0.5�m CMOS technology for the following specifications Use the one equation all region transistor model. Provide tables summarizing results and significant plots. Do not use CADENCE circuits figures in your report; draw your own (clean) circuit figures. Discuss the main results.
Proposed Telescopic OpAmp with Improved Gain
"... Abstract Before venturing further on the design of our operational amplifier, the first line of business is to determine the optimal topology for the given specifications. The factor that clearly stands out is the high dynamic range requirement of 85 db. Several topologies are given for this task, ..."
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Abstract Before venturing further on the design of our operational amplifier, the first line of business is to determine the optimal topology for the given specifications. The factor that clearly stands out is the high dynamic range requirement of 85 db. Several topologies are given for this task, among these telescopic opamp is selected. Compensation techniques are used with two stage topology of telescopic operational amplifier (opamp). Miller compensation technique is used with null resistor to obtain such a high gain. The opamp is designed on 0.13um technology CMOS process with 5 v power supply and achieved a dc gain of 85dB with a 177.1MHz unity gain frequency. Index Terms Opamp, miller capacitance, unity gain frequency, dc gain D I.