CMOS analog/digital circuit of the hysteresis McCulloch-Pitts neuron for Ramsey numbers

A parallel algorithm for finding Ramsey numbers is presented where analog/digital CMOS circuits for the hysteresis McCulloch-Pitts binary neuron are described. The hysteresis McCulloch-Pitts binary neuron model is used in order to suppress the oscillatory behaviors of neural dynamics so that the convergence time is shortened. The proposed algorithm using the hysteresis McCulloch-Pitts binary neuron found five Ramsey numbers. The analog CMOS sigmoid circuit with variable gain controls has been fabricated and tested using the SAC data acquisition board interfaced with a TMS 32010 processor. Hysteresis can be implemented by the positive feedback in the fabricated CMOS analog circuit.     

Area-efficient layout design for CMOS output transistors

A novel layout design to effectively reduce the layout area of the thin-oxide NMOS and PMOS devices in CMOS output buffers with ESD consideration is proposed. With respect to the traditional finger-type layout, the large-dimension output NMOS and PMOS devices are realized by multiple octagonal cells. Without using extra ESD-optimization process, the output NMOS and PMOS devices in this octagon-type layout can provide higher driving/sinking current and better ESD robustness within a smaller layout area. The drain-to-bulk parasitic capacitance at the output node is also reduced by this octagon-type layout. Experimental results in a 0.6-μm CMOS process have shown that the output driving (sinking) current of CMOS output buffers in per unit layout area is increased 47.7% (34.3%) by this octagon-type layout. The HBM (MM) ESD robustness of this octagon-type output buffer in per unit layout area is also increased 41.5% (84.6%), as comparing to the traditional finger-type output buffer. This octagon-type layout design makes a substantial contribution to the submicron or deep-submicron CMOS IC's in high-density and high-speed applications     

一种高速低功耗迟滞CMOS比较器的分析与设计

文章分析设计了一种具有内部迟滞效应的高速低功耗CMOS比较器,该比较器采用前置放大级、正反馈级和输出驱动级级联的结构,实现了对增益、速度和功耗的优化.电路的内部迟滞效应有效的实现了对噪声信号的抑制.采用0.35μm CMOS工艺的仿真结果表明,该比较器在3.3V的供电电源下可达到100MHz的工作速度.在20MHz的采样速率下具有0.2mW的功耗.芯片测试结果表明各项性能指标均达到了设计要求.     

Area efficient layout design of CMOS circuit for high-density ICs

Efficient layouts have been an active area of research to accommodate the greater number of devices fabricated on a given chip area. In this work a new layout of CMOS circuit is proposed, with an aim to improve its electrical performance and reduce the chip area consumed. The study shows that the design of CMOS circuit and SRAM cells comprising tapered body reduced source fully depleted silicon on insulator (TBRS FD-SOI)-based n- and p-type MOS devices. The proposed TBRS FD-SOI n- and p-MOSFET exhibits lower sub-threshold slope and higher I_on to I_off ratio when compared with FD-SOI MOSFET and FinFET technology. Other parameters like power dissipation, delay time and signal-to-noise margin of CMOS inverter circuits show improvement when compared with available inverter designs. The above device design is used in 6-T SRAM cell so as to see the effect of proposed layout on high density integrated circuits (ICs). The SNM obtained from the proposed SRAM cell is 565 mV which is much better than any other SRAM cell designed at 50 nm gate length MOS device. The Sentaurus TCAD device simulator is used to design the proposed MOS structure.     

Novel CMOS latch with clock hysteresis

A latch circuit is described which tolerates the use of slow and skewed clock signals. The low-complexity circuit has been shown to provide a safe alternative to the use of non-overlapping clocks, and enables the minimisation of clock interconnection and power.     

CMOS PLA自动版图设计系统

ＰＬＡ自动版图设计系统可以使设计者快速地得到时宏单元，从电路盒物理版图的细节中解放出来。由于ＰＬＡ较低的设计费用和可编程的特点，设计系统对于实现电路中的控制部分十分有效。     

Differential CMOS Schmitt trigger with tunable hysteresis

This letter presents a new differential Schmitt trigger with tunable hysteresis. The hysteresis is generated using a cross-coupled inverter pair. The amount of hysteresis can be adjusted by varying the current of the symmetrical load. The proposed Schmitt trigger has been designed in TSMC-0.18 μm 1.8 V CMOS technology and analyzed using Spectre from Cadence Design Systems with BSIM3V3 device models. Simulation results demonstrate that the triggering voltage of the Schmitt trigger can be adjusted from 0.95 to 1.35 V approximately.     

Novel CMOS Schmitt trigger with controllable hysteresis

A novel CMOS Schmitt trigger with controllable hysteresis based on the standard CMOS circuit with three transistor pairs is proposed. With the addition of only one transistor pair a Schmitt trigger with two selectable hysteresis characteristics can be achieved. Simulation results are compared with theory and a possible application is presented.<>     

A metal-oriented layout structure for CMOS logic

A design method is described for the realization of large digital modules of random logic for custom integrated circuits in CMOS technology. The layout structure is based on the gate matrix concept with a metal orientation instead of a polysilicon orientation. The symbolic layout is obtained by using 11 different microcells with simple assembly rules. It is derived from the functional specifications of the circuit (Karnaugh maps) using a very simple and attractive method. A CAD program for translating the symbolic layout into a geometrical one is described. It works by assembling geometrical microcells. The advantages and disadvantages of the metal-oriented structure are analyzed through examples of industrial designs. The technique is not suitable for fast circuits. However, it results in an improvement of productivity by a factor of about four and a packing density for large modules which is at least comparable with that of nonoriented hand layouts.     

New layout design for submicron CMOS output transistors to improve driving capability and ESD robustness

New layout design to effectively reduce the layout area of CMOS output transistors but with higher driving capability and better ESD reliability is proposed. The output transistors of large device dimensions are assembled by a plurality of the basic layout cells, which have the square, hexagonal or octagonal shapes. The output transistors realized by these new layout styles have more symmetrical device structures, which can be more uniformly triggered during the ESD-stress events. With theoretical calculation and experimental verification, both higher output driving/sinking current and stronger ESD robustness of CMOS output buffers can be practically achieved by the proposed new layout styles within a smaller layout area in the non-silicided bulk CMOS process. The output transistors assembled by a plurality of the proposed layout cells also have a lower gate resistance and a smaller drain capacitance than that realized by the traditional finger-type layout.     

Effect of IC layout on the reliability of CMOS amplifiers

With shrinking device size and increasing circuit complexity, interconnect reliability has become the main factor that affects the integrated circuit (IC) reliability. Electromigration (EM) is the major failure mechanism for interconnect reliability. However, little research had been done on the effect of IC layout on the void nucleation time (i.e. the time where the vacancies in the metal gather and nucleate into a tiny void) in the interconnections of the circuits due to electromigration using 3D modeling. In this paper, we construct the 3D models for a CMOS class-AB amplifier and a RF low noise amplifier (LNA), and investigate the impact of layout design on the void nucleation time through the computation of the atomic flux divergence (AFD) of the 3D circuit models. From the simulation results we find that, there is a change in the value of the maximum total AFD with the change in the number of contacts or the inter-transistor distance. A change in the location of the maximum total AFD is observed in the LNA circuit with different finger number as a result of the change in the line width and the transistor rotation. This indicates a different reliability lifetime and void formation location with different layout designs.     

CMOS current Schmitt trigger with fully adjustable hysteresis

A CMOS current Schmitt trigger whose hysteresis is independent of process parameters, transistor dimensions and power supplies is described. The hysteresis is determined by two currents and is adjustable over the range of the input current. The circuit function can be extended to a two-input current comparator with adjustable hysteresis.<>     

Millimeter-wave CMOS design

This paper describes the design and modeling of CMOS transistors, integrated passives, and circuit blocks at millimeter-wave (mm-wave) frequencies. The effects of parasitics on the high-frequency performance of 130-nm CMOS transistors are investigated, and a peak f/sub max/ of 135 GHz has been achieved with optimal device layout. The inductive quality factor (Q/sub L/) is proposed as a more representative metric for transmission lines, and for a standard CMOS back-end process, coplanar waveguide (CPW) lines are determined to possess a higher Q/sub L/ than microstrip lines. Techniques for accurate modeling of active and passive components at mm-wave frequencies are presented. The proposed methodology was used to design two wideband mm-wave CMOS amplifiers operating at 40 GHz and 60 GHz. The 40-GHz amplifier achieves a peak |S/sub 21/| = 19 dB, output P/sub 1dB/ = -0.9 dBm, IIP3 = -7.4 dBm, and consumes 24 mA from a 1.5-V supply. The 60-GHz amplifier achieves a peak |S/sub 21/| = 12 dB, output P/sub 1dB/ = +2.0 dBm, NF = 8.8 dB, and consumes 36 mA from a 1.5-V supply. The amplifiers were fabricated in a standard 130-nm 6-metal layer bulk-CMOS process, demonstrating that complex mm-wave circuits are possible in today's mainstream CMOS technologies.     

ALGA: Automated layout generator for analog CMOS circuits

A computer-aided design (CAD) system called ALGA for an analog circuit layout is presented. The main contribution of this paper is to construct a weight graph that represents the topological connectivity of a given analog circuit. By using the weight graph, some efficient techniques can be designed to avoid devices mismatch and place all devices according to the device size constraints. Moreover, an algorithm is presented to perform the device placement step and propose an effective approach to reduce noise coupling in the routing step. A design method has been implemented in several Complementary Metal Oxide Semiconductor (CMOS) analog circuits. It is seen that the proposed system can generate good analog circuit design.     

On the temperature dependence of hysteresis effect in floating-bodypartially depleted SOI CMOS circuits

This paper presents a detailed study on the temperature dependence of the hysteresis effect in static CMOS circuits and pass-transistor-based circuits with floating-body partially depleted (PD) silicon-on-insulator (SOI) CMOS devices. Basic physical mechanisms underlying the temperature dependence of hysteretic delay variations are examined. It is shown that, depending on the initial state of the circuit, the initial circuit delays have distinct temperature dependence. For steady-state circuit delays, the temperature dependence is dictated solely by the various charge injection/removing mechanisms into/from the body. The use of the cross-coupled dual-rail configuration in pass-transistor-based circuits is shown to be effective in compensating and reducing the disparity in the temperature dependence of the delays     

Investigation into effects of device variability on CMOS layout motifs

Sub-circuit motifs are proposed as a methodology for simulating the performance of sub-45 nm circuits exhibiting atomistic device fluctuations. Motifs allow the reduction of the problem space and create a standard motif library as a step in the design hierarchy for logic circuits. Device variability information from 3D simulation results is used that is incorporated into families of BSIM4 models. It is demonstrated how a thorough understanding of circuit behaviour can be obtained and the impact on current drive is illustrated by examining the effect of additional parasitic resistances.     

0.6μm CMOS工艺迟滞比较器的失配分析

本文对一个采用0.6μm CMOS工艺的迟滞比较器的失配性能进行了理论分析,探讨了关键部件的尺寸失配对该比较器迟滞性能的影响.Hspice仿真证明了理论分析的正确性;Monte Carlo仿真进一步分析了该比较器性能对失配参数的敏感性.本文的工作为今后的抗失配设计改进提供了方向.     

Millimeter-wave CMOS circuit design

We have developed a 27- and 40-GHz tuned amplifier and a 52.5-GHz voltage-controlled oscillator using 0.18-mum CMOS. The line-reflect-line calibrations with a microstrip-line structure, consisting of metal1 and metal6, was quite effective to extract the accurate S-parameters for the intrinsic transistor on an Si substrate and realized the precise design. Using this technique, we obtained a 17-dB gain and 14-dBm output power at 27 GHz for the tuned amplifier. We also obtained a 7-dB gain and a 10.4-dBm output power with a good input and output return loss at 40 GHz. Additionally, we obtained an oscillation frequency of 52.5 GHz with phase noise of -86 dBc/Hz at a 1-MHz offset. These results indicate that our proposed technique is suitable for CMOS millimeter-wave design