The next generation oflogic gate devices are expected to depend upon radically new technologies mainly due to the increasing difficulties and limitations of existing CMOS technology. MOSFET like CNFETs should ideally ...The next generation oflogic gate devices are expected to depend upon radically new technologies mainly due to the increasing difficulties and limitations of existing CMOS technology. MOSFET like CNFETs should ideally be the best devices to work with for high-performance VLS1. This paper presents results of a comprehensive comparative study of MOSFET-like carbon nanotube field effect transistors （CNFETs） technology based logic gate library for high-speed, low-power operation than conventional bulk CMOS libraries. It focuses on comparing four promising logic families namely： complementary-CMOS （C-CMOS）, transmission gate （TG）, complementary pass logic （CPL） and Domino logic （DL） styles are presented. Based on these logic styles, the proposed library of static and dynamic NAND-NOR logic gates, XOR, multiplexer and full adder functions are implemented efficiently and carefully analyzed with a test bench to measure propagation delay and power dissipation as a function of supply voltage. This analysis provides the right choice of logic style for low-power, high-speed applications. Proposed logic gates libraries are simulated using Synopsys HSPICE based on the standard 32 nm CNFET model. The simulation results demonstrate that, it is best to use C-CMOS logic style gates that are implemented in CNFET technology which are superior in performance compared to other logic styles, because of their low average powerdelay-product （PDP）. The analysis also demonstrates how the optimum supply voltage varies with logic styles in ultra-low power systems. The robustness of the proposed logic gate library is also compared with conventional and state-art of CMOS logic gate libraries.展开更多
This paper presents a novel approach to design robust Source Coupled Logic (SCL) for implementing ultra low power circuits. In this paper, we propose two different source coupled logic structures and analyze the perfo...This paper presents a novel approach to design robust Source Coupled Logic (SCL) for implementing ultra low power circuits. In this paper, we propose two different source coupled logic structures and analyze the performance of these structures with STSCL (Sub-threshold SCL). The first design under consideration is DTPMOS as load device which analyses the performance of Dynamic Threshold SCL (DTSCL) Logic with previous source coupled logic for ultra low power operation. DTSCL circuits exhibit a better power-delay Performance compared with the STSCL Logic. It can be seen that the proposed circuit provides 56% reduction in power delay product. The second design under consideration uses basic current mirror active load device to provide required voltage swing. Current mirror source coupled logic (CMSCL) can be used for high speed operation. The advantage of this design is that it provides 54% reduction in power delay product over conventional STSCL. The main drawback of this design is that it provides a higher power dissipation compared to other source coupled logic structures. The proposed circuit provides lower sensitivity to temperature and power supply variation, with a superior control over power dissipation. Measurements of test structures simulated in 0.18 μm CMOS technology shows that the proposed DTSCL logic concept can be utilized successfully for bias currents as low as 1 pA. Measurements show that existing standard cell libraries offer a good solution for ultra low power SCL circuits. Cadence Virtuoso schematic editor and Spectre Simulation tools have been used.展开更多
文摘The next generation oflogic gate devices are expected to depend upon radically new technologies mainly due to the increasing difficulties and limitations of existing CMOS technology. MOSFET like CNFETs should ideally be the best devices to work with for high-performance VLS1. This paper presents results of a comprehensive comparative study of MOSFET-like carbon nanotube field effect transistors （CNFETs） technology based logic gate library for high-speed, low-power operation than conventional bulk CMOS libraries. It focuses on comparing four promising logic families namely： complementary-CMOS （C-CMOS）, transmission gate （TG）, complementary pass logic （CPL） and Domino logic （DL） styles are presented. Based on these logic styles, the proposed library of static and dynamic NAND-NOR logic gates, XOR, multiplexer and full adder functions are implemented efficiently and carefully analyzed with a test bench to measure propagation delay and power dissipation as a function of supply voltage. This analysis provides the right choice of logic style for low-power, high-speed applications. Proposed logic gates libraries are simulated using Synopsys HSPICE based on the standard 32 nm CNFET model. The simulation results demonstrate that, it is best to use C-CMOS logic style gates that are implemented in CNFET technology which are superior in performance compared to other logic styles, because of their low average powerdelay-product （PDP）. The analysis also demonstrates how the optimum supply voltage varies with logic styles in ultra-low power systems. The robustness of the proposed logic gate library is also compared with conventional and state-art of CMOS logic gate libraries.
文摘This paper presents a novel approach to design robust Source Coupled Logic (SCL) for implementing ultra low power circuits. In this paper, we propose two different source coupled logic structures and analyze the performance of these structures with STSCL (Sub-threshold SCL). The first design under consideration is DTPMOS as load device which analyses the performance of Dynamic Threshold SCL (DTSCL) Logic with previous source coupled logic for ultra low power operation. DTSCL circuits exhibit a better power-delay Performance compared with the STSCL Logic. It can be seen that the proposed circuit provides 56% reduction in power delay product. The second design under consideration uses basic current mirror active load device to provide required voltage swing. Current mirror source coupled logic (CMSCL) can be used for high speed operation. The advantage of this design is that it provides 54% reduction in power delay product over conventional STSCL. The main drawback of this design is that it provides a higher power dissipation compared to other source coupled logic structures. The proposed circuit provides lower sensitivity to temperature and power supply variation, with a superior control over power dissipation. Measurements of test structures simulated in 0.18 μm CMOS technology shows that the proposed DTSCL logic concept can be utilized successfully for bias currents as low as 1 pA. Measurements show that existing standard cell libraries offer a good solution for ultra low power SCL circuits. Cadence Virtuoso schematic editor and Spectre Simulation tools have been used.
