A new 11 T SRAM cell with write-assist is proposed to improve operation at low supply voltage. In this technique, a negative bit-line voltage is applied to one of the write bit-lines, while a boosted voltage is applie...A new 11 T SRAM cell with write-assist is proposed to improve operation at low supply voltage. In this technique, a negative bit-line voltage is applied to one of the write bit-lines, while a boosted voltage is applied to the other write bit-line where transmission gate access is used in proposed 11 T cell. Supply voltage to one of the inverters is interrupted to weaken the feedback. Improved write feature is attributed to strengthened write access devices and weakened feedback loop of cell at the same time. Amount of boosting required for write performance improvement is also reduced due to feedback weakening, solving the persistent problem of half-selected cells and reliability reduction of access devices with the other suggested boosted and negative bit-line techniques. The proposed design improves write time by 79%, 63% and slower by 52% with respect to LP 10 T, WRE 8 T and 6 T cells respectively. It is found that write margin for the proposed cell is improved by about 4×, 2.4× and 5.37× compared to WRE8 T, LP10 T and 6 T respectively. The proposed cell with boosted negative bit line（BNBL） provides47%, 31%, and 68.4% improvement in write margin with respect to no write-assist, negative bit line（NBL） and boosted bit line（BBL） write-assist respectively. Also, new sensing circuit with replica bit-line is proposed to give a more precise timing of applying boosted voltages for improved results. All simulations are done on TSMC 45 nm CMOS technology.展开更多
This paper presents a 6 kb SRAM that uses a novel 10T cell to achieve a minimum operating voltage of 320 mV in a 130 nm CMOS process. A number of low power circuit techniques are included to enable the proposed SRAM t...This paper presents a 6 kb SRAM that uses a novel 10T cell to achieve a minimum operating voltage of 320 mV in a 130 nm CMOS process. A number of low power circuit techniques are included to enable the proposed SRAM to operate in the subthreshold region. The reverse short channel effect and the reverse narrow channel effect are utilized to improve the performance of the SRAM. A novel subthreshold pulse generation circuit produces an ideal pulse to make read operation stable. A floating write bit-line effectively reduces the standby leakage consumption. Finally, a short read bit-line makes the read operation fast and energy-saving. Measurements indicate that these techniques are effective, the SRAM can operate at 800 kHz and consume 1.94/zW at its lowest voltage （320 mV）.展开更多
With technology scaling,stability,power dissipation,and device variability,the impact of process,voltage and temperature(PVT)variations has become dominant for static random access memory(SRAM)analysis for productivit...With technology scaling,stability,power dissipation,and device variability,the impact of process,voltage and temperature(PVT)variations has become dominant for static random access memory(SRAM)analysis for productivity and failure.In this paper,ten-transistors(10T)and low power eight-transistors SRAM cells are redesigned using floating-gate MOS transistors(FGMOS).Power centric parameters viz.read power,write power,hold power and delay are the performance analysis metrics.Further,the stochastic parameter variation to study the variability tolerance of the redesigned cell,PVT variations and Monte Carlo simulations have been carried out for 10T FGMOS SRAM cell.Stability has been illustrated with the conventional butterfly method giving read static noise margin(RSNM)and write static noise margin(WSNM)metrics for read stability and write ability,respectively.A comparative analysis with standard six-transistor SRAM cell is carried out.HSPICE simulative analysis has been carried out for 32 nm technology node.The redesigned FGMOS SRAM cells provide improved performance.Also,these are robust and reliability efficient with comparable stability.展开更多
文摘A new 11 T SRAM cell with write-assist is proposed to improve operation at low supply voltage. In this technique, a negative bit-line voltage is applied to one of the write bit-lines, while a boosted voltage is applied to the other write bit-line where transmission gate access is used in proposed 11 T cell. Supply voltage to one of the inverters is interrupted to weaken the feedback. Improved write feature is attributed to strengthened write access devices and weakened feedback loop of cell at the same time. Amount of boosting required for write performance improvement is also reduced due to feedback weakening, solving the persistent problem of half-selected cells and reliability reduction of access devices with the other suggested boosted and negative bit-line techniques. The proposed design improves write time by 79%, 63% and slower by 52% with respect to LP 10 T, WRE 8 T and 6 T cells respectively. It is found that write margin for the proposed cell is improved by about 4×, 2.4× and 5.37× compared to WRE8 T, LP10 T and 6 T respectively. The proposed cell with boosted negative bit line（BNBL） provides47%, 31%, and 68.4% improvement in write margin with respect to no write-assist, negative bit line（NBL） and boosted bit line（BBL） write-assist respectively. Also, new sensing circuit with replica bit-line is proposed to give a more precise timing of applying boosted voltages for improved results. All simulations are done on TSMC 45 nm CMOS technology.
基金Project supported by the National Natural Science Foundation of China(No.61306039)the Next Generation of Information Technology for Sensing China(No.XDA06020401)
文摘This paper presents a 6 kb SRAM that uses a novel 10T cell to achieve a minimum operating voltage of 320 mV in a 130 nm CMOS process. A number of low power circuit techniques are included to enable the proposed SRAM to operate in the subthreshold region. The reverse short channel effect and the reverse narrow channel effect are utilized to improve the performance of the SRAM. A novel subthreshold pulse generation circuit produces an ideal pulse to make read operation stable. A floating write bit-line effectively reduces the standby leakage consumption. Finally, a short read bit-line makes the read operation fast and energy-saving. Measurements indicate that these techniques are effective, the SRAM can operate at 800 kHz and consume 1.94/zW at its lowest voltage （320 mV）.
文摘With technology scaling,stability,power dissipation,and device variability,the impact of process,voltage and temperature(PVT)variations has become dominant for static random access memory(SRAM)analysis for productivity and failure.In this paper,ten-transistors(10T)and low power eight-transistors SRAM cells are redesigned using floating-gate MOS transistors(FGMOS).Power centric parameters viz.read power,write power,hold power and delay are the performance analysis metrics.Further,the stochastic parameter variation to study the variability tolerance of the redesigned cell,PVT variations and Monte Carlo simulations have been carried out for 10T FGMOS SRAM cell.Stability has been illustrated with the conventional butterfly method giving read static noise margin(RSNM)and write static noise margin(WSNM)metrics for read stability and write ability,respectively.A comparative analysis with standard six-transistor SRAM cell is carried out.HSPICE simulative analysis has been carried out for 32 nm technology node.The redesigned FGMOS SRAM cells provide improved performance.Also,these are robust and reliability efficient with comparable stability.
