scholarly journals Pre-Emphasis Pulse Design for Random-Access Memory

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1454
Author(s):  
Yoshihiro Sugiura ◽  
Toru Tanzawa

This paper describes how one can reduce the memory access time with pre-emphasis (PE) pulses even in non-volatile random-access memory. Optimum PE pulse widths and resultant minimum word-line (WL) delay times are investigated as a function of column address. The impact of the process variation in the time constant of WL, the cell current, and the resistance of deciding path on optimum PE pulses are discussed. Optimum PE pulse widths and resultant minimum WL delay times are modeled with fitting curves as a function of column address of the accessed memory cell, which provides designers with the ability to set the optimum timing for WL and BL (bit-line) operations, reducing average memory access time.

Author(s):  
Harekrishna Kumar ◽  
V. K. Tomar

In the proposed work, a differential write and single-ended read half-select free 12 transistors static random access memory cell is designed and simulated. The proposed cell has a considerable reduction in power dissipation with better stability and moderate performance. This cell operates in subthreshold region and has a higher value of read static noise margin as compared to conventional six transistors static random access memory cell. A power cut-off technique is utilized between access and pull-up transistors during the write operation. It results in an increase in write static noise margin as compared to all considered cells. In the proposed cell, read and write access time is improved along with a reduction in read/write power dissipation as compared to conventional six transistors static random access memory cell. The bitline leakage current in the proposed cell is reduced which improves the [Formula: see text] ratio of the cell under subthreshold region. The proposed cell occupies less area as compared to considered radiation-hardened design 12 transistors static random access memory cell. The computed electrical quality metric of proposed cell is better among considered static random access memory cells. Process variation analysis of read stability, access time, power dissipation, read current and leakage current has been performed with the help of Monte Carlo simulation at 3,000 points to get more soundness in the results. All characteristics of static random access memory cells are compared at various supply voltages.


Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 614
Author(s):  
Zhisheng Chen ◽  
Renjun Song ◽  
Qiang Huo ◽  
Qirui Ren ◽  
Chenrui Zhang ◽  
...  

Three-dimensional vertical resistive random access memory (VRRAM) is proposed as a promising candidate for increasing resistive memory storage density, but the performance evaluation mechanism of 3-D VRRAM arrays is still not mature enough. The previous approach to evaluating the performance of 3-D VRRAM was based on the write and read margin. However, the leakage current (LC) of the 3-D VRRAM array is a concern as well. Excess leakage currents not only reduce the read/write tolerance and liability of the memory cell but also increase the power consumption of the entire array. In this article, a 3-D circuit HSPICE simulation is used to analyze the impact of the array size and operation voltage on the leakage current in the 3-D VRRAM architecture. The simulation results show that rapidly increasing leakage currents significantly affect the size of 3-D layers. A high read voltage is profitable for enhancing the read margin. However, the leakage current also increases. Alleviating this conflict requires a trade-off when setting the input voltage. A method to improve the array read/write efficiency is proposed by analyzing the influence of the multi-bit operations on the overall leakage current. Finally, this paper explores different methods to reduce the leakage current in the 3-D VRRAM array. The leakage current model proposed in this paper provides an efficient performance prediction solution for the initial design of 3-D VRRAM arrays.


2021 ◽  
Vol 16 (1) ◽  
pp. 114-118
Author(s):  
Wan-Jun Yin ◽  
Tao Wen ◽  
Wei Zhang

This paper presents the design analysis of Dynamic Random Access Memory (DRAM) with one transistor one diode (1T1D). The proposed structure consists of one transistor and one voltage controlled diode capacitor. The word and bit lines are connected with two voltage sources for the write operation. The source and drain of the NMOS is tied together to form the diode structure. The off-state leakage current is the main cause for the power dissipation of DRAM. Thus the improvement of power efficiency to the overall system is a critical task. The conventional DRAM cell contains one capacitor and one transistor. But the absence of capacitor in the proposed work is advantageous by means of compatibility, scalability, fabrication complexity, and cost. Tanner EDA working platform of 7 nm technology is used for the implementation of 1T1D DRAM cell in proposed work. This work achieve the power dissipation, read and write access time in the range of 2.647 mW, 0.04 μs and 0.021 μs respectively. Also, the parameter comparison is performed by changing the technologies from 10 nm to 20 nm for 1T1D DRAM cell design.


Author(s):  
Ashish Sachdeva ◽  
V. K. Tomar

This paper presents a circuit-level technique of designing a low power and half select free 10T Static Random-Access Memory Cell (SRAM). The proposed cell works with single end read operation and differential write operation. The proposed bit-cell is free from half select issue and supports bit interleaving format. The presented 10T cell exhibits 40.75% lower read power consumption in comparison to conventional 6T SRAM cell, attributed to reduction of activity factor during read operation. The loop cutting transistors used in core latch improve write signal-to-noise margin (WSNM) by 14.94% and read decoupled structure improve read signal-to-noise margin (RSNM) by [Formula: see text] as compared to conventional 6T SRAM. In the proposed work, variability analysis of significant design parameters such as read current, stand-by SNM, and read power of the projected 10T SRAM cell is presented and compared with considered topologies. Mean value of hold static noise margin of the cell for 3000 samples is [Formula: see text] times higher than the considered D2p11T cell. The proposed 10T cell shows [Formula: see text] and [Formula: see text] narrower read access time and write access time, respectively, as compared to conventional 6T SRAM cell. Read current to bit-line leakage current ratio of the proposed 10T cell has been investigated and is improved by [Formula: see text] as compared to conventional 6T SRAM cell. The write power delay product and read power delay product of the proposed 10T cell are [Formula: see text] and [Formula: see text] lower than conventional 6T SRAM cell. In this work, cadence virtuoso tool with Generic Process Design Kit (GPDK) 45[Formula: see text]nm technology file has been utilized to carry out simulations.


2006 ◽  
Vol 45 (5A) ◽  
pp. 3955-3958 ◽  
Author(s):  
X. S. Miao ◽  
L. P. Shi ◽  
H. K. Lee ◽  
J. M. Li ◽  
R. Zhao ◽  
...  

2020 ◽  
Vol 29 (01n04) ◽  
pp. 2040010
Author(s):  
R. H. Gudlavalleti ◽  
B. Saman ◽  
R. Mays ◽  
Evan Heller ◽  
J. Chandy ◽  
...  

This paper presents the peripheral circuitry for a multivalued static random-access memory (SRAM) based on 2-bit CMOS cross-coupled inverters using spatial wavefunction switched (SWS) field effect transistors (SWSFETs). The novel feature is a two quantum well/quantum dot channel n-SWSFET access transistor. The reduction in area with four-bit storage-per-cell increases the memory density and efficiency of the SRAM array. The SWSFET has vertically stacked two-quantum well/quantum dot channels between the source and drain regions. The upper or lower quantum charge locations in the channel region is based on the input gate voltage. The analog behavioral modeling (ABM) of the SWSFET device is done using conventional BSIM 3V3 device parameters in 90 nm technology. The Cadence circuit simulations for the proposed memory cell and addressing/peripheral circuitry are presented.


2021 ◽  
Vol 21 (8) ◽  
pp. 4216-4222
Author(s):  
Songyi Yoo ◽  
In-Man Kang ◽  
Sung-Jae Cho ◽  
Wookyung Sun ◽  
Hyungsoon Shin

A capacitorless one-transistor dynamic random-access memory cell with a polysilicon body (poly-Si 1T-DRAM) has a cost-effective fabrication process and allows a three-dimensional stacked architecture that increases the integration density of memory cells. Also, since this device uses grain boundaries (GBs) as a storage region, it can be operated as a memory cell even in a thin body device. GBs are important to the memory characteristics of poly-Si 1T-DRAM because the amount of trapped charge in the GBs determines the memory’s data state. In this paper, we report on a statistical analysis of the memory characteristics of poly-Si 1T-DRAM cells according to the number and location of GBs using TCAD simulation. As the number of GBs increases, the sensing margin and retention time of memory cells deteriorate due to increasing trapped electron charge. Also, “0” state current increases and memory performance degrades in cells where all GBs are adjacent to the source or drain junction side in a strong electric field. These results mean that in poly-Si 1T-DRAM design, the number and location of GBs in a channel should be considered for optimal memory performance.


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