The enhancement CMOS design brings more difficulties, which is specially say that for SRAM, that is the unfavourable memory block of SoC. In this paper we present the design procedure of single stage operational amplifier and multistage operational amplifier. In this paper we have simulated the diode connected load with two extra PMOS which get the better trade-off among the output swing voltage, voltage gain and the common mode range. The properties of operational amplifier are high input impedance, low output impedance and it also contains the high gain. We take the dimension of transistors with width W = 2.5µm and length L = 0.25µm. Here we have used the 0.25µm CMOS technology.
The conventional DCDL uses the double clocked flip-flop as a driving circuit , . This is one of the special flip-flops which employs two different clock signals, so that it can provide different delays for LH and HL transitions. One of these clock signals is CLH. I.e., Clock signal rises when low to high transitions. Another one is CHL. I.e., Clock signal falls when high to low transitions. But this too have some of the drawbacks such as consumption of more power and consumes more delay time. This senseamplifier based flip-flop consists of senseamplifier in the first stage and set-reset (SR) latch in the next stage. This conventional flip-flop is shown in the Figure-4. This sensing stage capture the input signal state on the clock rising edges and a latch stage provides the two flip-flop outputs are detailed in Figure-4 and can be
F06 and F07 are two flip-flops that are very close to one another. The pre-charged sense-amplifierstage is very fast, but the set-reset latch almost doubles the delay due to unequal rise and fall times. This might cause glitches in succeeding logic stages; increasing the power consumption of these stages. F06 has better delay performance but suffers from floating output node of the senseamplifierstage if the data changes during the high phase of the clock, but still it has very low clock load which is an advantage in power consumption. F07 improves on the leakage power consumption.
II. Block diagram of twostage CMOS op-amp Operational Amplifiers are the backbone for many analog circuit designs. Op-Amps are one of the basic and important circuits which have a wide application in several analog circuit such as switched capacitor filters, algorithmic, pipelined and sigma delta A/D converter, sample and hold amplifier etc. The speed and accuracy of these circuits depends on the bandwidth and DC gain of the Op-amp. Larger the bandwidth and gain, higher the speed and accuracy of the amplifier Op-amp are a critical element in analog sampled data circuit, such as SC filters, modulators. The general block diagram of an op-amp with an output buffer is shown below
The problem in the design of first comparator circuit shown in Fig.1 is when the differencce between the two analog input reaches zero. Even a small amount of noise can cause spurious fluctuation in the comparator output. These fluctuations causes unnecessary power consumption in comparator circuit and also false result are produced. In practical applicatons noise can effect the output of the comparator. In fig.2 we can see how the output get affected with noisy input signal.
As shown in Figure.7, when the power amplifier works at 2140MHz, drain voltage is 28V and the current is 500mA, the gain is about 15dB, the largest output power is about 47dBm, and the PAE at the largest output power is about 41%. By contrast with the performance from software design, it is obviously that the performances from big signal measurement have a little degraded. The deterioration is inevitable. Because the computer design and simulation is under the ideal situation, computer cannot think about the complex actual circumstances. But the overall measurements are under the real condition, there are so many potential factors impact the performance of the power amplifier, such as the circuit machining precision, sample transistor condition. After all, the performance of power amplifier has some deterioration, but it is acceptable.
The principle of chopper amplifier is illustrated in adjoining figure. The signal at the input is first modulated by the chopping frequency fchop and chopping signal i.e. m (t) with and shifted to odd harmonics of the chopping frequency. Whereas Vos and Vn denote the dc offset and noise of the amplifier, respectively. Resultant amplified signal is modulated which then demodulated to the even harmonics, noise and DC offset before the amplifier is just modulated once and shifted to the odd harmonics of the chopping frequency. Through a post low-pass filter, the noise and dc offset are filter out, leaving base-band input signal without any distortion. To prevent attenuation of input signal which is converted to fchop, the cut off frequency of chopper amplifiers should be higher than the chopping frequency, and a post low-pass filter is need to filter modulated noise. Thus the conventional chopper Amplifier consumes large power and comprises of complicated circuitry. A low-noise and low power consumption amplifier has been a vital for detecting the signals with small values. It is mostly used in biomedical information systems. EEG (electroencephalogram) and ECG (electrocardiogram) have characteristics of low amplitude and low frequency [1-2]. The bandwidth of the signal is from 3Hz to 100Hz and amplitude less than 100 μV and in case of EEG signals bandwidth is from 1Hz to 150 Hz and amplitude less than 5mV. These signals require precise designing of the acquisition and recording units for capturing and storing these signals. So the low noise, low power and the low offset amplifier are the key circuit for detecting the small signal levels in the information system of biomedical stream, 45nm CMOS technology is implemented due to its low power consumption capability, dense integration and low cost. Moreover in technology implementing CMOS processes 1/f noise becomes a serious problem. It limits the minimum detectable signal at low frequency. So as an associated approach to design a high precision amplifier, chopping technique is widely used, it has an advantage of having low noise and low offset characteristics.
The Langmuir probe has been developed to find out the electron-density Mars ionosphere. The golden coated cylindrical sensor is input stage of this system. Here we discuss implementation of Langmuir Probe experiment system. We apply to sweep voltage to sensor to collection of the current and collected current goes to feedback operational amplifier. The feedback resistor and gain of the succeeding amplifierstage in output voltage of the system between 1 to 5 Volts. The output of the feedback operational amplifier is goes to differential amplifierstage we also apply sweep voltage to differential amplifier so differential amplifier have a two input one coming from sensor and another one is sweep voltage, differential amplifier is amplify difference between both of the signals finally we got actual signal coming from sensor. Here we used opa445ap high voltage input impedance operational amplifier.
Abstract- In this paper we have examined the sensitivity Of Current Mirror Senseamplifier at different values of Vdd and W/L ratio.We have verified the results of sensitivity at 180 nano meter technology. In this Paper we will see that when Vdd increases circuit ability to avoid the noise also increases and thus increases the efficiency of circuit. Simulation results shows that efficiency of SenseAmplifier increases with increasing supply voltage and decreases with decrease in W/L ratio.
path to the other electrode of it, for initiating a resultant force between them. This creates a displacement which will initiate a capacitive transduction and will produce a capacitive current. As shown in Fig. 2, a transimpedance amplifier (TIA) will convert this tiny displacement current into a voltage signal and in consecutive voltage amplifier blocks (intermediate VA and cascode amplifier) a net high gain would make this signal sustain at the excitation electrode of the MEMS. In this way, in the feedback loop, the sustaining amplifier would ensure the necessary loss compensation by a tuned Gain-BW product. Additionally, AGC (automatic gain control) block can beintegratedin improving the oscillation properties such as phase noise, tuning ability, variable gain, etc. For measuring purposes, there are output buffer amplifiers to drive at least 50Ω impedances such that, it could not load the original alternating voltage signal. The sustaining block designed in this work contains three stages: transimpedance amplifier (TIA), intermediate voltage amplifier and a high gain cascode amplifier. The oscillation output (voltage signal) is extracted out through the 50Ωoutput buffer (unity gain) amplifier. In this regard, a detailed demonstration of each of the blocks is given. 3.1 TransimpedanceAmplifier (TIA):
power, has led to the development of these technologies. In 1998, the first CMOS RF power amplifier was made with 1W power delivery at the 2GHz frequency range, with PAE = 41% and 2V power supply . Simultaneously with the developments in the wireless communication industry, tremendous improvements in semiconductor technology emerged. Among them, the most significant progress was the development of CMOS technology. CMOS transistors' remarkable feature is that the speed will increase, while it consumes less power per function than digital and analog circuits which results in reducing the circuit cost and size. Therefore, the ultimate goal of engineers and researchers in the process is putting the power amplifier, IC transmitter and receiver, power management module and digital bandwidth on a piece of Si, GaAs or GaN. Wireless communication systems require high linear power amplifier to send a signal with minimum phase and amplitude distortion. Bandwidth, efficiency, linearity system and desirable output power are four basic and determinant factors for RF microwave power amplifier in the modern communication systems. Improving efficiency and achieving a high output power simultaneously, has proposed a useful design method which is a promising solution, using various classes of power amplifier (Single or Mix). Usually, power amplifiers are based on their configuration and their performance conditions, and are classified in various classes (eg, Class A, B, C, AB, D, F, F -1 , S, G, J, etc). Classes A, B, C, AB, depending on the
In this analysis, it has been sufficiently demonstrated that h-parameters for transistor amplifiers can be correctly realized using mathematical equations as opposed to the derivation of transistor operating conditions from its characteristics curve at a certain operating regions. From the results obtained, it has been shown that the h-parameter performance quantities of a small signal transistor can be derived fundamentally using the transistor two-port network system for the three configurations of the transistor amplifier. The results has also adequately represented the operation and actions of a small signal transistor in impedance matching and various transistor gains.
Block diagram  of Op-amp is as shown in Fig. 1. The input stage consists of a differential amplifier which provides high CMRR, high input impedance and high voltage gain. The second stage is a gain stage which further increases the gain. Gain stage is a common source amplifier. Circuit symbol of op-amp is shown by Fig. 2. It consists of inverting input and non-inverting input with an output which is amplified version of difference in the inputs. It is a single supply op-amp, whose main advantage is reduced power. However the output voltage swing reduces compared to dual supply op-amp and lies between positive supply and ground. Op-amp characteristics are high open loop gain (ideally infinity), high Bandwidth (ideally infinity), high input impedance (ideally infinity), low output impedance (ideally zero), high CMRR (ideally infinity) and high PSRR (ideally infinity). Op-amp has wide range of applications ranging from filtering, dc bias generation, amplification and data conversion. General purpose applications include addition, subtraction,integration, differentiation, buffering and inversion.
 H.C. Chow and P.N. Weng "A Low Voltage Rail-to-Rail OPAMP Design for Biomedical Signal Filtering Applications," Electronic Design, Test and Applications, 2008. DELTA 2008. 4th IEEE International Symposium on , vol., no., pp.232-235, 23-25 Jan. 2008  M. Sani and A. A. Hamoui ,"A 1-V Process-Insensitive Current- Scalable Two-Stage Opamp With Enhanced DC Gain and Settling Behavior in 65-nm Digital CMOS," Solid-State Circuits, IEEE Journal of , vol.46, no.3, pp.660-668, March 2011
This work presents a novel design method of two-stage CMOS OTA which has been designed and compared with a basic two-stage CMOS OTA. Behavioural simulation indicated that phase margin is 60° to ensure a good stability, gain of 57 dB for ±1.5V without using a gain boosting technique, and GBW of 55 MHz is sufficient to design the ADC converter. The applied technique leads to a significant preservation in gain bandwidth product (GBW), gain (Av), slew rate (SR), and decrease power consumption. The design technique proposed in this paper combines better performance with simplicity of design and suitability for high frequency operation with few modifications on conventional two-stage CMOS OTA and at low power consumption.
This paper is presents to design a twostage CMOS operational amplifier and analyze the effect of various aspect ratios on the characteristics of this op-amp, which operates at 1V power supply and using 32nm, 45nm, 90nm, 130nm, 180nm technology. In this paper trade-off curves are computed between all characteristics such as Gain, PM, O/P Swing, Slew Rate. The op-amp designed is a two-stage CMOS op-amp. Design has been carried out in tanner tools. The task of CMOS operational amplifiers (op-amps) design optimization is investigated in this work. This paper focuses on the optimization of different aspect ratio, which gives the results of the different parameters. When the task is analyzed as a search problem, it can be converted into an operational amplifier in which a variety of specifications, the Gain, PM, and other multi-objective optimization application. As a result, with respect to the operational amplifier having a standard feature helps graphics and tables under comparison. The simulation results agree with the theoretical predictions. Keywords: CMOS Analog circuit, Two-Stage CMOS Operational Amplifier, Scaling, Tanner, 32nm, 45nm, 90nm, 130nm, 180nm.
The recommended method for connecting the HCPL-788J to the current sensing resistor is shown in Figure 26. V IN+ (pin 1 of the HCPL-788J) is con- nected to the positive terminal of the sense resis- tor, while V IN- (pin 2) is shorted to GND 1 (pin 8), with the power-supply return path functioning as the sense line to the negative terminal of the current sense resistor. This allows a single pair of wires or PC board traces to connect the HCPL-788J circuit to the sense resistor. By referencing the input circuit to the neg- ative side of the sense resistor, any load current induced noise transients on the resistor are seen as a common- mode signal and will not interfere with the current-sense signal. This is important because the large load currents flowing through the motor drive, along with the para- sitic inductances inherent in the wiring of the circuit, can generate both noise spikes and offsets that are rela tively large compared to the small voltages that are being measured across the current sensing resistor.
ABSTRACT: In this paper a CMOS twostage operational amplifier is presented which operates with 2.5 V power supply at 0.18 micron (i.e., 180 nm) technology, whose input is depending on Bias Current. To reduce overall power consumption of the system the supply voltage has been scaled down. The main aim is to decrease power dissipation. There is a trade-off among speed, power and gain at large supply voltages. Performance of any circuit depends upon speed, power and gain. Designed op-amp has very low standby power consumption with a large driving capability and operates at low voltage so that the circuit operates at low power. The twostage CMOS op-amp provides a gain of 52.80dB and a -3db bandwidth of 21.01kHz and a unity gain bandwidth of 9.20 MHz for a load considered of 3 pF compensation capacitor & 10pF load Capacitor. It has a PSRR (+) of 111.66dB, with a high CMRR of 117.10 dB and an output slew rate of 22.82 v/μs. The power consumption for the op-amp is 0.775mW.
resolution. Narrow-band technology such as Bluetooth confront with the problem of multipath fading which is described as signal loss due to the destructive interference of continuous wave (CW) signals . Next, the problem in NB is that the signals transmit are insecure because NB signals are easily detected and jammed . Narrow-band signals also facing a problem of poor range resolution for tracking applications and limited data rate because narrow RF bandwidth means narrow data bandwidth . In general, the RF performance of the Power Amplifier is excellent if it able to achieve the high gain, high output power, and high power added efficiency. By designing only a single stageamplifier, we cannot provide a high gain, high output power, high power added efficiency, and high stability amplifier as expected. As for the different biasing circuit, active biasing does not offer much advantage over the passive biasing circuit so the matching networks can be changed to either lumped elements, shunt stub or quarter wave matching techniques for space reduction and cost saving. The developing of amplifier based on Distributed Amplifier technique will enhance performance in term of output power but affect the power added efficiency. There is also a problem of some conventional power amplifier design not support the whole range of UWB licensed bandwidth from 3.1 GHz to 10.6 GHz.