scholarly journals Design and PVT Analysis of Robust, High Swing Folded Cascode Operational Amplifier

2019 ◽  
Vol 9 (2) ◽  
pp. 114-118
Keyword(s):  
Power Dissipation ◽  
Operational Amplifier ◽  
Low Voltage ◽  
Cmos Technology ◽  
Current Mirror ◽  
Op Amp ◽  
Multistage Amplifiers ◽  
Pvt Variations ◽  
Folded Cascode ◽  
Voltage Swing

The folded cascode operational amplifier (FCOA) designed in this paper is the single-pole operational amplifier (op amp). In this design, the conventional current mirror is replaced with wide swing current mirror to overcome the essential drawback of cascode configuration. In this paper, negative feedback is used to improve the small-signal gain and to ensure better stability than multistage amplifiers. This paper also aims at improving the output voltage swing, power dissipation and robustness of the op amp. The designed FCOA is proficient in achieving 67.44dB gain and 1.77V output swingat typical voltage for 180nm CMOS technology. The FCOA is highly stable with phase margin of 62.58º while dissipating 0.5mW power. This amplifier is further verified for variability analysis for Process, Voltage and Temperature (PVT) variations to check robustness. All together testing is done at 45 different PVT combinations and results are tabulated accordingly. At each corner temperature and voltage are varied for all together nine combinations to properly address the effect of PVT variations. The results shows that the op amp exhibits desired response at four corners (FF, TT, SS, and FS) of process, over -40º to 125º C temperature range. Also it is capable of operating at very low voltage up to 0.9V adequately showing reduction in power dissipation. Thus the designed op amp is low power, high swing and robust towards process, voltage and temperature variations.

scholarly journals DESIGN OF LOW VOLTAGE LOW POWER OPERATIONAL AMPLIFIER

2015 ◽  
pp. 257-261
Author(s):  
M.I.SUDHA RAYAPPA ◽  
V. SURENDRA BABU
Keyword(s):  
Power Supply ◽  
Power Dissipation ◽  
Operational Amplifier ◽  
Noise Level ◽  
Low Voltage ◽  
High Gain ◽  
Op Amp ◽  
Technology Improvement ◽  
Supply Voltages ◽  
Analog Systems

This Thesis presents a design of the Folded-cascade operational amplifier which leads to high gain as compared to a normal cascade circuit. In this project; specifications of analog systems into op amp level net-lists of library components is studied and simulated using XILINX. As the power-supply voltages because of the technology improvement and it are desired to reduce power supply to minimize power dissipation, many challenges are faced by the analog designer. One is to keep noise level as possible. The op-amp must be designed to with the ever decreasing power supply voltages. As the power supply voltages begin to approach 2Vt, new technique and new op-amp topology like folded cascade should be used.

Low voltage and low frequency current mirror using a two-MOS subthreshold OP-Amp

1996 ◽  
Vol 32 (7) ◽  
pp. 605 ◽  
Author(s):  
K. Tanno ◽  
O. Ishizuka ◽  
Z. Tang
Keyword(s):  
Low Voltage ◽  
Low Frequency ◽  
Current Mirror ◽  
Op Amp ◽  
Frequency Current

Design of Low Voltage Low Power LPF for WSN Node

2013 ◽  
Vol 760-762 ◽  
pp. 54-59
Author(s):  
Yang Lin ◽  
Zhi Qun Li ◽  
Chen Jian Wu ◽  
Meng Zhang ◽  
Zeng Qi Wang
Keyword(s):  
Low Power ◽  
Low Voltage ◽  
Frequency Tuning ◽  
Cmos Technology ◽  
Pass Band ◽  
Automatic Frequency ◽  
Temperature Deviation ◽  
Op Amp ◽  
Active Rc Filter ◽  
Operation Amplifier

A fourth-order low-pass continuous-time filter for a WSN transmitter is presented. The active RC filter was chosen for the high linearity, designed by using the leapfrog topology imitates the passive filter. The operation amplifier (op-amp) adopted by the filter is feed-forward operation amplifier, which could get the GBW as large as possible under the low power consumption. The cut-off frequency deviation due to the process corner, aging and temperature deviation is adjusted by an automatic frequency tuning circuit. The filter in a 0.18μm RF CMOS technology consumes 1mW from a 1V power supply. The measured results of the chip show that the bandwidth is about 1.5MHz. The voltage gain of filter is about-4.5dB with the buffer, the ripple in the pass-band is lower than 0.5 dB, and the channel rejection ratio is larger than 30dB at 4MHz.

A 1-mm2 CMOS-pipelined ADC with integrated folded cascode operational amplifier

2020 ◽  
Vol 37 (4) ◽  
pp. 205-213
Author(s):  
Norhamizah Idros ◽  
Zulfiqar Ali Abdul Aziz ◽  
Jagadheswaran Rajendran
Keyword(s):  
Operational Amplifier ◽  
Open Loop ◽  
Cmos Process ◽  
Silicon Area ◽  
Content Type ◽  
Op Amp ◽  
Dc Gain ◽  
Input Range ◽  
Folded Cascode ◽  
The Impact

Purpose The purpose of this paper is to demonstrate the acceptable performance by using the limited input range towards lower open-loop DC gain operational amplifier (op-amp) of an 8-bit pipelined analog-to-digital converter (ADC) for mobile communication application. Design/methodology/approach An op-amp with folded cascode configuration is designed to provide the maximum open-loop DC gain without any gain-boosting technique. The impact of low open-loop DC gain is observed and analysed through the results of pre-, post-layout simulations and measurement of the ADC. The fabrication process technology used is Silterra 0.18-µm CMOS process. The silicon area by the ADC is 1.08 mm2. Findings Measured results show the differential non-linearity (DNL) error, integral non-linearity (INL) error, signal-to-noise ratio (SNR) and spurious-free dynamic range (SFDR) are within −0.2 to +0.2 LSB, −0.55 LSB for 0.4 Vpp input range, 22 and 27 dB, respectively, with 2 MHz input signal at the rate of 64 MS/s. The static power consumption is 40 mW with a supply voltage of 1.8 V. Originality/value The experimental results of ADC showed that by limiting the input range to ±0.2 V, this ADC is able to give a good reasonable performance. Open-loop DC gain of op-amp plays a critical role in ADC performance. Low open-loop DC gain results in stage-gain error of residue amplifier and, thus, leads to nonlinearity of output code. Nevertheless, lowering the input range enhances the linearity to ±0.2 LSB.

Monolayer Graphene Field Effect Transistor-Based Operational Amplifier

2019 ◽  
Vol 28 (03) ◽  
pp. 1950052
Author(s):  
Ali Safari ◽  
Massoud Dousti ◽  
Mohammad Bagher Tavakoli
Keyword(s):  
Operational Amplifier ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Cmos Technology ◽  
Design System ◽  
Monolayer Graphene ◽  
Characteristic Curves ◽  
Op Amp ◽  
Graphene Field Effect Transistor ◽  
Effect Transistor

Graphene Field Effect Transistor (GFET) is a promising candidate for future high performance applications in the beyond CMOS roadmap for analog circuit applications. This paper presents a Verilog-A implementation of a monolayer graphene field-effect transistor (mGFET) model. The study of characteristic curves is carried out using advanced design system (ADS) tools. Validation of the model through comparison with measurements from the characteristic curves is carried out using Silvaco TCAD tools. Finally, the mGFET is used to design a GFET-based operational amplifier (Op-Amp). The GFET Op-Amp performances are tuned in term of the graphene channel length in order to obtain a reasonable gain and bandwidth. The main characteristics of the Op-Amp performance are compared with 0.18[Formula: see text][Formula: see text]m CMOS technology.

scholarly journals A Positive Feedback-Based Op-Amp Gain Enhancement Technique for High-Precision Applications

2020 ◽  
Vol 29 (14) ◽  
pp. 2050220
Author(s):  
Rajasekhar Nagulapalli ◽  
Khaled Hayatleh ◽  
Steve Barker
Keyword(s):  
Positive Feedback ◽  
Cmos Technology ◽  
Voltage Gain ◽  
Silicon Area ◽  
Power Efficient ◽  
Enhancement Technique ◽  
Op Amp ◽  
Gain Enhancement ◽  
Pvt Variations ◽  
Boosting Technique

A power-efficient, voltage gain enhancement technique for op-amps has been described. The proposed technique is robust against Process, Voltage and Temperature (PVT) variations. It exploits a positive feedback-based gain enhancement technique without any latch-up issue, as opposed to the previously proposed conductance cancellation techniques. In the proposed technique, four additional transconductance-stages (gm stages) are used to boost the gain of the main gm stage. The additional gm stages do not significantly increase the power dissipation. A prototype was designed in 65[Formula: see text]nm CMOS technology. It results in 81[Formula: see text]dB voltage gain, which is 21[Formula: see text]dB higher than the existing gain-boosting technique. The proposed op-amp works with as low a power supply as 0.8[Formula: see text]V, without compromising the performance, whereas the traditional gain-enhancement techniques start losing gain below a 1.1[Formula: see text]V supply. The circuit draws a total static current of 295[Formula: see text][Formula: see text]A and occupies 5000[Formula: see text][Formula: see text]m2 of silicon area.

AN ULTRA LOW-VOLTAGE/POWER-EFFICIENT ALL-DIGITAL DELAY LOCKED LOOP IN 55 nm CMOS TECHNOLOGY

2012 ◽  
Vol 21 (08) ◽  
pp. 1240025 ◽  
Author(s):  
CHUN-YUAN CHENG ◽  
JINN-SHYAN WANG ◽  
CHENG-TAI YEH
Keyword(s):  
Low Power ◽  
Power Dissipation ◽  
Low Voltage ◽  
Cmos Technology ◽  
Maximum Frequency ◽  
Clock Frequency ◽  
Power Efficient ◽  
Delay Locked Loop ◽  
Measurement Results ◽  
Variation Tolerance

This paper presents an all-digital delay locked loop (ADDLL) that uses asynchronous-deskewing technology and achieves low power/voltage, small jitter, fast locking, and high process, voltage, and temperature (PVT)-variation tolerance. The measurement results show that the maximum frequency is 100 MHz at 0.35 V with 19 μW power dissipation, 62 ps peak-to-peak jitter, and 3 locking cycles. When operated at 0.5 V, the measured maximal operating clock frequency is 450 MHz with 12 ps peak-to-peak jitter, 6 locking cycles and 119 μW power dissipation. The ADDLL is fabricated with 55 nm CMOS technology, and the active area is only 0.019 mm2.

Low Power Operational Transconductance Amplifier (OTA) with Enhanced DC Gain and Slew-Rate

2013 ◽  
Vol 411-414 ◽  
pp. 1645-1648
Author(s):  
Xiao Zong Huang ◽  
Lun Cai Liu ◽  
Jian Gang Shi ◽  
Wen Gang Huang ◽  
Fan Liu ◽  
...  
Keyword(s):  
Low Voltage ◽  
Cmos Technology ◽  
Optimization Techniques ◽  
Current Mirror ◽  
Slew Rate ◽  
Operational Transconductance Amplifier ◽  
Theory Analysis ◽  
Transconductance Amplifier ◽  
Dc Gain ◽  
Simulation Results

This paper presents a low-voltage differential operational transconductance amplifier (OTA) with enhanced DC gain and slew-rate. Based on the current mirror OTA topology, the optimization techniques are discussed in this work. The proposed structure achieves enhanced DC gain, unit gain frequency (UGF) and slew-rate (SR) with adding four devices. The design of the OTA is described with theory analysis. The OTA operates at the power supply of 1.8V. Simulation results for 0.18μm standard CMOS technology show that the DC gain increases from 60.6dB to 65dB, the UGF is optimized from 2.5MHz to 4.3MHz, the SR is enhanced from 0.88 V/μs to 4.8 V/μs with close power consumption dramatically.

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