A read-disturb-free stable low power and high-density GNRFET 6T SRAM with multi-VT technology

Circuit World ◽  
2020 ◽  
Vol 46 (3) ◽  
pp. 203-214
Author(s):  
Pramod Kumar Patel ◽  
M.M. Malik ◽  
Tarun Kumar Gutpa

Purpose The performance of the conventional 6T SRAM cell can be improved by using GNRFET devices with multi-threshold technology. The proposed cell shows the strong capability to operate at the minimum supply voltage of 325 mV, whereas the conventional Si-CMOS 6 T SRAM unable to operate below 725 mV, which result in an acceptable failure rate.The advance of Si-CMOS (complementary metal-oxide-semiconductor) based 6 T SRAM cell faces inherent limitation with aggressive downscaling. Hence, there is a need to propose alternatives for the conventional cells. Design/methodology/approach This study aims to improve the performance of the conventional 6T SRAM cell using dual threshold technology, device sizing, optimization of supply voltage under process variation with GNRFET technology. Further performance can be enhanced by resolving half-select issue. Findings The GNRFET-based 6T SRAM cell demonstrates that it is capable of continued improve the performance under the process, voltage, and temperature (PVT) variations significantly better than its CMOS counterpart. Research limitations/implications Nano-material fabrication technology of GNRFETs is in the early stage; hence, the different transistor models can be used to evaluate the parameters of future GNRFETs circuit. Practical implications GNRFET devices are suitable for implementing low power and high density SRAM cell. Social implications The conventional Si-CMOS 6 T SRAM cell is a core component and used as the mass storage element in cache memory in computer system organization, mobile phone and other data storage devices. Originality/value This paper presents a new approach to implement an alternative design of GNRFET -based 6T SRAM cell with doped reservoirs that also supports process variation. In addition, multi-threshold technology optimizes the performance of the proposed cell. The proposed design provides a means to analyze delay and power of GNRFET-based SRAM under process variation with considering edge roughness, and offers design and fabrication insights for cell in the future.

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.


Circuit World ◽  
2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sandeep Garg ◽  
Tarun Kumar Gupta

Purpose This paper aims to propose a new fin field-effect transistor (FinFET)-based domino technique low-power series connected foot-driven transistors logic in 32 nm technology and examine its performance parameters by performing transient analysis. Design/methodology/approach In the proposed technique, the leakage current is reduced at footer node by a division of current to improve the performance of the circuit in terms of average power consumption, propagation delay and noise margin. Simulation of existing and proposed techniques are carried out in FinFET and complementary metal-oxide semiconductor technology at FinFET 32 nm technology for 2-, 4-, 8- and 16-input domino OR gates on a supply voltage of 0.9 V using HSPICE. Findings The proposed technique shows maximum power reduction of 77.74% in FinFET short gate (SG) mode in comparison with current-mirror-based process variation tolerant (CPVT) technique and maximum delay reduction of 51.34% in low power (LP) mode in comparison with CPVT technique at a frequency of 100 MHz. The unity noise gain of the proposed circuit is 1.10× to 1.54× higher in comparison with different existing techniques in FinFET SG mode and 1.11× to 1.71× higher in FinFET LP mode. The figure of merit of the proposed circuit is up to 15.77× higher in comparison with existing domino techniques. Originality/value The research proposes a new FinFET-based domino technique and shows improvement in power, delay, area and noise performance. The proposed design can be used for implementing high-speed digital circuits such as microprocessors and memories.


Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Muhammad Yasir Faheem ◽  
Shun'an Zhong ◽  
Muhammad Basit Azeem ◽  
Xinghua Wang

Purpose Successive Approximation Register-Analog to Digital Converter (SAR-ADC) has been achieved notable technological advancement since the past couple of decades. However, it’s not accurate in terms of size, energy, and time consumption. Many projects proposed to make it energy efficient and time-efficient. Such designs are unable to deliver two parallel outputs. Design/methodology/approach To this end, this study introduced an ultra-low-power circuitry for the two blocks (bootstrap and comparator) of 11-bit SAR-ADC. The bootstrap has three sub-parts: back-bone, left-wing and right-wing, named as bat-bootstrap. The comparator block has a circuitry of the two comparators and an amplifier, named as comp-lifier. In a bat-bootstrap, the authors plant two capacitors in the back-bone block to avoid the patristic capacitance. The switching system of the proposed design highly synchronized with the short pulses of the clocks for high accuracy. This study simulates the proposed circuits using a built-in Cadence 90 nm Complementary Metal Oxide Semiconductor library. Findings The results suggested that the response time of two bat-bootstrap wings and comp-lifier are 80 ns, 120 ns, and 90 ns, respectively. The supply voltage is 0.7 V, wherever the power consumption of bat-bootstrap, comp-lifier and SAR-ADC are 0.3561µW, 0.257µW and 35.76µW, respectively. Signal to Noise and Distortion Ratio is 65 dB with 5 MHz frequency and 25 KS/s sampling rate. The input referred noise of the amplifier and two comparators are 98µVrms, 224µVrms and 224µVrms, respectively. Originality/value Two basic circuit blocks for SAR-ADC are introduced, which fulfill the duality approach and delivered two outputs with highly synchronized clock pulses. The circuit sharing concept introduced for the high performance SAR-ADCs.


2020 ◽  
Vol 17 (6) ◽  
pp. 803-809
Author(s):  
Vaithiyanathan D. ◽  
Megha Singh Kurmi ◽  
Alok Kumar Mishra ◽  
Britto Pari J.

Purpose In complementary metal-oxide-semiconductor (CMOS) logic circuits, there is a direct square proportion of supply voltage on dynamic power. If the supply voltage is high, then more amount of energy will be consumed. Therefore, if a low voltage supply is used, then dynamic power will also be reduced. In a mixed signal circuit, there can be a situation when lower voltage circuitry has to drive large voltage circuitry. In such a case, P-type metal-oxide-semiconductor of high-voltage circuitry may not be switched off completely by applying a low voltage as input. Therefore, there is a need for level shifter where low-voltage and high-voltage circuits are connected. In this paper the multi-scaling voltage level shifter is presented which overcomes the contention problems and suitable for low-power applications. Design/methodology/approach The voltage level shifter circuit is essential for digital and analog circuits in the on-chip integrated circuits. The modified voltage level shifter and reported energy-efficient voltage level shifter have been optimally designed to be functional in all process voltage and temperature corners for VDDH = 5V, VDDL = 2V and the input frequency of 5 MHz. The modified voltage level shifter and reported shifter circuits are implemented using Cadence Virtuoso at 90 nm CMOS technology and the comparison is made based on speed and power consumed by the circuit. Findings The voltage level shifter circuit discussed in this paper removes the contention problem that is present in conventional voltage level shifter. Moreover, it has the capability for up and down conversion and reduced power and delay as compared to conventional voltage level shifter. The efficiency of the circuit is improved in two ways, first, the current of the pull-up device is reduced and second, the strength of the pull-down device is increased. Originality/value The modified level shifter is faster for switching low input voltage to high output voltage and also high input voltage to low output voltage. The average power consumption for the multi-scaling voltage level shifter is 259.445 µW. The power consumption is very less in this technique and it is best suitable for low-power applications.


2017 ◽  
Vol MCSP2017 (01) ◽  
pp. 7-10 ◽  
Author(s):  
Subhashree Rath ◽  
Siba Kumar Panda

Static random access memory (SRAM) is an important component of embedded cache memory of handheld digital devices. SRAM has become major data storage device due to its large storage density and less time to access. Exponential growth of low power digital devices has raised the demand of low voltage low power SRAM. This paper presents design and implementation of 6T SRAM cell in 180 nm, 90 nm and 45 nm standard CMOS process technology. The simulation has been done in Cadence Virtuoso environment. The performance analysis of SRAM cell has been evaluated in terms of delay, power and static noise margin (SNM).


Author(s):  
Kanan Bala Ray ◽  
Sushanta Kumar Mandal ◽  
Shivalal Patro

<em>In this paper floating gate MOS (FGMOS) along with sleep transistor technique and leakage control transistor (LECTOR) technique has been used to design low power SRAM cell. Detailed investigation on operation, analysis and result comparison of conventional 6T, FGSRAM, FGSLEEPY, FGLECTOR and FGSLEEPY LECTOR has been done. All the simulations are done in Cadence Virtuoso environment on 45 nm standard CMOS technology with 1 V power supply voltage. Simulation results show that FGSLEEPY LECTOR SRAM cell consumes very low power and achieves high stability compared to conventional FGSRAM Cell</em>


Circuit World ◽  
2020 ◽  
Vol 46 (3) ◽  
pp. 183-192
Author(s):  
Muhammad Yasir Faheem ◽  
Shun'an Zhong ◽  
Xinghua Wang ◽  
Muhammad Basit Azeem

Purpose Successive approximation register (SAR) analogue to digital converter (ADC) is well-known with regard to low-power operations. To make it energy-efficient and time-efficient, scientists are working for the last two decades, and it still needs the attention of the researchers. In actual work, there is no mechanism and circuitry for the production of two simultaneous comparator outputs in SAR ADC. Design/methodology/approach A small-sized, low-power and energy-efficient circuitry of a dual comparator and an amplifier is presented, which is the most important part of SAR ADC. The main idea is to design a multi-dimensional circuit which can deliver two quick parallel comparisons. The circuitry of the three devices is combined and miniaturized by introducing a lower number of MOSFET’s and small-sized capacitors in such a way that there is no need for any matching and calibration. Findings The supply voltage of the proposed comparator is 0.7 V with the overall power consumption of 0.257mW. The input and clock frequencies are 5 and 50 MHz, respectively. There is no requirement for any offset calibration and mismatching concerns due to sharing and centralization of spider-latch circuitry. The total offset voltages are 0.13 0.31 mV with 0.3VDD to VDD. All the components are small-sized and miniaturized to make the circuit cost-effective and energy-efficient. The rise and response time of comparator is around 100 ns. SNDR improved from 56 to 65 dB where the input-referred noise of an amplifier is 98mVrms. Originality/value The proposed design has no linear-complexity compared with the conventional comparator in both modes (working and standby); it is ultimately intended and designed for 11-bit SAR ADC. The circuit based on three rapid clock pulses for three different modes includes amplification and two parallel comparisons controlled and switched by a latch named as “spider-latch”.


2021 ◽  
Author(s):  
T. Santosh Kumar ◽  
Suman Lata Tripathi

Abstract The SRAM cells are used in many applications where power consumption will be the main constraint. The Conventional 6T SRAM cell has reduced stability and more power consumption when technology is scaled resulting in supply voltage scaling, so other alternative SRAM cells from 7T to 12T have been proposed which can address these problems. Here a low power 7T SRAM cell is suggested which has low power consumption and condensed leakage currents and power dissipation. The projected design has a leakage power of 5.31nW and leakage current of 7.58nA which is 84.9% less than the 7T SRAM cell without using the proposed leakage reduction technique and it is 22.4% better than 6T SRAM and 22.1% better than 8T SRAM cell when both use the same leakage reduction technique. The cell area of the 7T SRAM cell is 1.25µM2, 6T SRAM is 1.079µM2 and that of 8T SRAM is 1.28µM2all the results are simulated in cadence virtuoso using 18nm technology.


2019 ◽  
Vol 28 (10) ◽  
pp. 1950165 ◽  
Author(s):  
Sandeep Garg ◽  
Tarun K. Gupta

In this paper, a fin field-effect transistor (FinFET)-based domino technique dynamic node-driven feedback transistor domino logic (DNDFTDL) is designed for low-power, high-speed and improved noise performance. In the proposed domino technique, the concept of current division is explored below the evaluation network for enhancement of performance parameters. Simulations are carried out for 32-nm complementary metal–oxide–semiconductor (CMOS) and FinFET node using HSPICE for 2-, 4-, 8- and 16-input OR gates with a DC supply voltage of 0.9[Formula: see text]V. Proposed technique shows a maximum power reduction of 73.93% in FinFET short-gate (SG) mode as compared to conditional stacked keeper domino logic (CSKDL) technique and a maximum power reduction of 72.12% as compared to modified high-speed clocked delay domino logic (M-HSCD) technique in FinFET low-power (LP) mode. The proposed technique shows a maximum delay reduction of 35.52% as compared to voltage comparison domino (VCD) technique in SG mode and a reduction of 25.01% as compared to current mirror footed domino logic (CMFD) technique in LP mode. The unity noise gain (UNG) of the proposed circuit is 1.72–[Formula: see text] higher compared to different existing techniques in FinFET SG mode and is 1.42–[Formula: see text] higher in FinFET LP mode. The Figure of Merit (FOM) of the proposed circuit is up to [Formula: see text] higher as compared to existing domino logic techniques because of lower values of power, delay and area and higher values of UNG of the proposed circuit. In addition, the proposed technique shows a maximum power reduction of up to 68.64% in FinFET technology as compared to its counterpart in CMOS technology.


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