Design and mathematical analysis of a 7T SRAM cell with enhanced read SNM using PMOS as an access transistor

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Alok Kumar Mishra ◽  
Vaithiyanathan D. ◽  
Yogesh Pal ◽  
Baljit Kaur

Purpose This work is proposed for low power energy-efficient applications like laptops, mobile phones, and palmtops. In this study, P-channel metal–oxide–semiconductor (PMOS)’s are used as access transistor in 7 transistors (7 T) Static Random Access Memory (SRAM) cell, and the theoretical Static Noise Margin (SNM) analysis for the proposed cell is also performed. A cell is designed using 7 T which consists of 4 PMOS and 3 NMOS. In this paper write and hold SNM is addressed and read SNM is also calculated for the proposed 7 T SRAM cell. Design/methodology/approach The authors have replaced N-channel metal–oxide–semiconductor (NMOS) access transistors with the PMOS access transistors, which results in proper data line recovery and provides the desired coupling. An error is likely to occur, if the read operation is performed too often probably by using the NMOS pass gate. It results in an improper recovery of the data line. Instead, by using PMOS as a pass gate, the time required for read operation can be brought down. As we know the mobility (µ) of the PMOS transistor is low, so the authors have used this property into the proposed design. When a low signal is applied to its control gate, the PMOS transistor come up with the desired coupling, when working as a pass gate. Findings Feedback switched transistor is used in the proposed circuit, which plays an important role in the write operation. This transistor is in OFF state and PMOS’s work as access transistor, when the proposed cell operating in read mode. This helps in the reduction of power. This work is simulated using UMC 40 nm technology node in the cadence virtuoso environment. The simulated result shows that, write power saving of 51.54% and 61.17%, hold power saving of 25.68% and 48.93% when compared with reported 7 T and 6 T, respectively. Originality/value The proposed 7 T SRAM cell provides proper data line recovery at a lower voltage when PMOS works as the access transistor. Power consumption is very less in this technique and it is best suitable for low power applications.

2019 ◽  
Vol 29 (05) ◽  
pp. 2050080
Author(s):  
M. Elangovan ◽  
K. Gunavathi

Designing of Complementary Metal Oxide Semiconductor (CMOS) technology based VLSI circuits in deep submicron range includes many challenges like tremendous increase of leakage power. Design is also easily affected by process variation. The Carbon NanoTube Field Effect Transistor (CNTFET) is an alternative for Metal Oxide Semiconductor Field Effect Transistor (MOSFET) for nanoscale range VLSI circuits design. CNTFET offers best performance than MOSFET. It has high stability and consumes least power. Static Random Access Memory (SRAM) cells play a vital role in cache memory in most of the electronic circuits. In this paper, we have proposed a high stable and low power CNTFET based 8Transistor (8T) SRAM cell. The performance of proposed 8T SRAM cells for nominal chiral value (all CNTFET with [Formula: see text], [Formula: see text]) and Dual chiral value (NCNTFET with [Formula: see text], [Formula: see text] and PCNTFET [Formula: see text], [Formula: see text]) is compared with that of conventional 6T and 8T cells. From the simulation results, it is noted that the proposed structure consumes less power than conventional 6T and 8T cells during read/write operations and gives higher stability during write and hold modes. It consumes higher power than conventional 6T and 8T cells during hold mode and provides lower stability in read mode due to direct contact of bit lines with storage nodes. A comparative analysis of proposed and conventional 8T MOSFET SRAM has been done and the SRAM parameters are tabulated. The simulation is carried out using Stanford University 32[Formula: see text]nm CNTFET model in HSPICE simulation tool.


2014 ◽  
Vol 13 (02) ◽  
pp. 1450012 ◽  
Author(s):  
Manorama Chauhan ◽  
Ravindra Singh Kushwah ◽  
Pavan Shrivastava ◽  
Shyam Akashe

In the world of Integrated Circuits, complementary metal–oxide–semiconductor (CMOS) has lost its ability during scaling beyond 50 nm. Scaling causes severe short channel effects (SCEs) which are difficult to suppress. FinFET devices undertake to replace usual Metal Oxide Semiconductor Field Effect Transistor (MOSFETs) because of their better ability in controlling leakage and diminishing SCEs while delivering a strong drive current. In this paper, we present a relative examination of FinFET with the double gate MOSFET (DGMOSFET) and conventional bulk Si single gate MOSFET (SGMOSFET) by using Cadence Virtuoso simulation tool. Physics-based numerical two-dimensional simulation results for FinFET device, circuit power is presented, and classifying that FinFET technology is an ideal applicant for low power applications. Exclusive FinFET device features resulting from gate–gate coupling are conversed and efficiently exploited for optimal low leakage device design. Design trade-off for FinFET power and performance are suggested for low power and high performance applications. Whole power consumptions of static and dynamic circuits and latches for FinFET device, believing state dependency, show that leakage currents for FinFET circuits are reduced by a factor of over ~ 10X, compared to DGMOSFET and ~ 20X compared with SGMOSFET.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Francisco Javier Plascencia Jauregui ◽  
Agustín Santiago Medina Vazquez ◽  
Edwin Christian Becerra Alvarez ◽  
José Manuel Arce Zavala ◽  
Sandra Fabiola Flores Ruiz

Purpose This study aims to present a mathematical method based on Poisson’s equation to calculate the voltage and volume charge density formed in the substrate under the floating gate area of a multiple-input floating-gate metal-oxide semiconductor metal-oxide semiconductor (MOS) transistor. Design/methodology/approach Based on this method, the authors calculate electric fields and electric potentials from the charges generated when voltages are applied to the control gates (CG). This technique allows us to consider cases when the floating gate has any trapped charge generated during the manufacturing process. Moreover, the authors introduce a mathematical function to describe the potential behavior through the substrate. From the resultant electric field, the authors compute the volume charge density at different depths. Findings The authors generate some three-dimensional graphics to show the volume charge density behavior, which allows us to predict regions in which the volume charge density tends to increase. This will be determined by the voltages on terminals, which reveal the relationship between CG and volume charge density and will allow us to analyze some superior-order phenomena. Originality/value The procedure presented here and based on coordinates has not been reported before, and it is an aid to generate a model of the device and to build simulation tools in an analog design environment.


Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 223 ◽  
Author(s):  
Yannan Zhang ◽  
Ke Han ◽  
and Jiawei Li

Ultra-low power and high-performance logical devices have been the driving force for the continued scaling of complementary metal oxide semiconductor field effect transistors which greatly enable electronic devices such as smart phones to be energy-efficient and portable. In the pursuit of smaller and faster devices, researchers and scientists have worked out a number of ways to further lower the leaking current of MOSFETs (Metal oxide semiconductor field effect transistor). Nanowire structure is now regarded as a promising candidate of future generation of logical devices due to its ultra-low off-state leaking current compares to FinFET. However, the potential of nanowire in terms of off-state current has not been fully discovered. In this article, a novel Core–Insulator Gate-All-Around (CIGAA) nanowire has been proposed, investigated, and simulated comprehensively and systematically based on 3D numerical simulation. Comparisons are carried out between GAA and CIGAA. The new CIGAA structure exhibits low off-state current compares to that of GAA, making it a suitable candidate of future low-power and energy-efficient devices.


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