Design Of Two Stage High Gain Opamp

Design Of Two Stage High Gain Opamp A High Swing Ultra-Low-Power Two Stage CMOS OP-AMP in 0.18 um Technology with 1.2v supply, is presented. Cascode technique has been used to increase the dc gain. The unity-gain bandwidth is also enhanced using a gain-stage in the Miller capacitor feedback path. The proposed opamp provides 236MHz unity-gain bandwidth, 109.7 degree phase margin. The circuit has 94.34dB gain. The power dissipation of the designed only is approximately 50uw. The designed system demonstrates relatively suitable response in different temperature. (1)Introduction:-Operational Amplifiers (Op amps) are one of the most widely used building blocks for analog and mixed-signal systems. They are employed from dc bias applications to high speed amplifiers and  ¬Ã‚ lters. General purpose op amps can be used as bu ¬Ã¢â€š ¬ers, summers, integrators, di ¬Ã¢â€š ¬erentiators, comparators, negative impedance converters, and many other applications. With the quick improvements of computer aided design (CAD) tools, advancements of semiconductor modeling, steady miniaturization of transistor scaling, and the progress of fabrication processes, the integrated circuit market is growing rapidly. Nowadays, complementary metal-oxide semiconductor (CMOS) technology has become dominant over bipolar technology for analog circuit design in a mixed-signal system due to the industry trend of applying standard process technologies to implement both analog circuits and digital circuits on the same chip. While many digital circuits can be adapted to a smaller device level with a smaller power supply, most existing analog circuitry requires considerable change or even a redesign to accomplish the same feat. With transistor length being scaled down to a few tens of nanometers, analog circuits are becoming increasingly more di ¬Ã†â€™cult to improve upon. The operational amplifier is one of the most useful and important components of analog electronics. They are widely used in popular electronics. Their primary limitation is that they are not especially fast: The typical performance degrades rapidly for frequencies greater than about 1 MHz, although some models are designed specifically to handle higher frequencies. The primary use of op-amps in amplifier and related circuits is closely connected to the Concept of negative feedback. Feedback represents a vast and interesting topic in itself. We will discuss it in rudimentary terms a bit later. However, it is possible to get a feeling for the two primary types of amplifier circuits, inverting and non-inverting, by simply postulating a few simple rules (the golden rules). We will start in this way, and then go back to understand their origin in terms of feedback. (2)Basic Block diagram 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 circuits 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 http://s.eeweb.com/members/jessica_shoemaker/projects/2011/03/22/Image1-1300812338.png Figure 1. Block diagram of Op-Amp The first block is a differential amplifier. It has two inputs which are the inverting and non-inverting voltage. It provides at the output a differential voltage or a differential current that, essentially, depends on the differential input only. The next block is a differential to single-ended converter. It is used to transform the differential signal generated by the first block into a single ended version. Some architecture doesnt require the differential to single ended function; therefore the block can be excluded. In most cases the gain provided by the input stages is not sufficient and additional amplification is required. This is provided by intermediate stage, which is another differential amplifier, driven by the output of the first stage. As this stage uses differential input unbalanced output differential amplifier, so it provide required extra gain. The bias circuit is provided to establish the proper operating point for each transistor in its saturation region. Finally , we have the output buffer stage. It provides the low output impedance and larger output current needed to drive the load of op-amp or improves the slew rate of the op -amp. Even the output stage can be dropped: many integrated applications do not need low output impedance; moreover, the slew rate permitted by the gain stage can be sufficient for the application. If the op-amp is intended to drive a small purely capacitive load, which is the case in many switched capacitor or data conversion applications, the output buffer is not used. When the output stage is not used the circuit, it is an operational transconductance amplifier, OTA. The purpose of the compensation circuit is lower the gain at high frequencies and to maintain stability when negative feedback is applied to the op amp. A. Circuit Operation The final circuit designed to meet the required specifications is shown in Figure 2. The topology of this circuit is that of a standard CMOS op-amp. It comprised of three subsections of http://www.silvaco.com/tech_lib_TCAD/simulationstandard/1995/mar/a2/a2_fig1.gif Figure2. The topology chosen for this Op-Amp design. Circuit, namely differential gain stage, second gain stage and bias strings. It was found that this topology was able to successfully meet all of the design specifications. B. Differential Gain Stage Transistors M1, M2, M3, and M4 form the first stage of the op amp the differential amplifier with differential to single ended transformation. Transistors M1 and M2 are standard N channel MOSFET (NMOS) transistors which form the basic input stage of the amplifier. The gate of M1 is the inverting input and the gate of M2 is the non-inverting input. A differential input signal applied across the two input terminals will be amplified according to the gain of the differential stage. The gain of the stage is simply the transconductance of M2 times the total output resistance seen at the drain of M2. The two main resistances that contribute to the output resistance are that of the input transistors themselves and also the output resistance of the active load transistors, M3 and M4. The current mirror active load used in this circuit has three distinct advantages. First, the use of active load devices creates a large output resistance in a relatively small amount of die area. The current mi rror topology performs the differential to single-ended conversion of the input signal, and finally, the load also helps with common mode rejection ratio. In this stage, the conversion from differential to single ended is achieved by using a current mirror (M3 and M4). The current from M1 is mirrored by M3 and M4 and subtracted from the current from M2. The differential current from M1 and M2 multiplied by the output resistance of the first stage gives the single-ended output voltage, which constitutes the input of the second gain stage. C. Second Gain Stage The second stage is a current sink load inverter. The purpose of the second gain stage, as the name implies, is to provide additional gain in the amplifier. Consisting of transistors M5 and M6, this stage takes the output from the drain of M2 and amplifies it through M5 which is in the standard common source configuration. Again, similar to the differential gain stage, this stage employs an active device, M6, to serve as the load resistance for M5. The gain of this stage is the transconductance of M5 times the effective load resistance comprised of the output resistances of M5 and M6. M6 is the driver while M7 acts as the load. (3)Design of the op-amp The design in this project is a two-stage op amp with an n-channel input pair. The op amp uses a dual-polarity power supply (Vdd and Vss) so the ac signals can swing above and below ground and also be centered at ground. The hand calculation results provided the estimated parameters (such as transistor width and length, capacitance, etc.) to make the circuit schematic (shown in figure) in Design Architect IC and for the circuit analysis in Model Sim Eldo of Mentor Graphic Tool.Schematic used in this design is C:Documents and SettingsstudentDesktop44132421.png Design of two stage opamp using mentor graphics (4)Simulation Result Using Mentor Graphics EDA Tool we have design High Swing Ultra-Low-Power Two Stage CMOS OP-AMP as shown in schematic window. Fig 1 Fig 2 shows the Gain and Phase plot for basic two stage opamp. After simulation we have analyzed that the gain of the opamp is 94.34db and have a phase margin of 109.7 degree at 40 MHz frequency. This analysis can be made possible using different sizing of the MOS transistor at different stages. There graphs are as C:UsersDellDesktopopampGAIN GRAPH.png Fig. 1 Gain graph C:UsersDellDesktopopampPM.png Fig.2 phase margin plot From the reference paper[14] we have seen that the gain is 90 db which is improves up to 94.3db which is used in any of Analog designing. Table shows the brief of results as PARAMETERS VALUE PROCESS TECHNOLOGY 180nm GAIN 94.34 db PHASE MARGIN 109.7 ° at 40MHZ

Drink and Home Countries

When I woke up that day, I was so excited because we were going to go to the holiday. I had packed my stuff the day before. And then we were ready to go! That was my first fly and I was anxious a little bit but my mother told me that there was no reason to be anxious. After an hour, we finally landed to Antalya. Then we arrived to the hotel. While bellboy was carrying our stuff to our room, I was thinking about what will I do next. I decided to go to the pool but I lost my way to the pool. There was noone to help me and I was so scared.Then I found my way to the pool because my cousin arrived my help. We had so much fun in the pool. We dived and danced in the pool. There were some tourists at the pool and we talked with them. One of them is Shymi. She is a Russian. Other one is Harry. He is a British. After we met, we decided to drink something and went to the cafe. My cousin and I ordered lemonade, Shymi ordered coke and Ollie ordered some icetea. While we were drinking our drinks, we talked about our home countries. Shymi told that she like to feel warmth on her skinbut she can barely see the sun in Russia.And Harry said that he can barely see the sun either, because of the pouring rain. After a little more chit-chat, dinner time came and 4 of us went to the dining hall. We ate something, took our drinks and went to the coast. We sat somewhere and while we were dirinking our sodas, we talked abour ourselves. At that time, sea was amazing. While they were talking, My thoughts were engulfed by the sound of waves. That was really amazing. Relaxing sounds took me so inside of them that I couldn’t hear what they said to me. After we sang some songs, we went to our rooms to sleep.Next day I woke up so happy and when I looked my cousin, I saw that she wasn’t wake up yet but my sister had woken up already. I whispered her to go to the bathroom and bring some water. She did what I told and we spilled the water to her face. She woke up screaming and start ed to chase us in the room. We went to the breakfast and ate some careal, drunk some orange juice. As my mother said, when you eat something, you should wait 30 minutes before swim. Otherwise bad things can happen. We played some table tenis while we were waiting. After 45 minutes, we went to the pool and met there with Shymi and Harry.

Adversity and Its Effects in a Man for All Seasons

A Man for all Seasons is a play that was written by prolific English writer, Robert Bolt. Born in 1924, he worked as an insurance agent before joining the World War II as a Royal Air Force officer. He worked as a school teacher, after his time at the force, before embarking on writing this particular play. The same year he wrote it; it featured as a play in London and New York. It is crucial to understand the background of the play to understand it with more power. According to Kincaid, it is useful to understand that for many years in England there had been hostility to the clergy, because the Church had great worldly powers, property, and wealth, while many members of the clergy were corrupt and self-seeking. (11) With this play, Bolt wanted to bring out the strong characteristic steadiness of standing on one’s feet and owns ground in what one believes irrespective of what others think or say. The main character, Sir Thomas More, is a judge who is steadfast and firm in his beliefs. He is not easily swayed by people’s opinions, influence, threats, and intimidation. He objects to endorsing King Henry VIII’s plan of divorcing his wife, Catherine of Aragon, and marry Anne Boleyn. The King having promoted Sir Thomas to the position of Lord Chancellor of England, and Thomas being his long standing friend, will automatically guarantee Sir Thomas agreeing to support him. He wants Thomas to publicly endorse his divorce plan, but Thomas More feels Henry’s actions are not justified, and the divorce is not appropriate. This is backed by Greene when he affirms that even as Nobles, universities and the Clergy fell into line behind the King, More’s silence on the matter resounded thunderously. Despite the king’s unhappiness with More’s decision to remain silent, he stands firm and refuse to do what everybody else did even though the pressure on his family grew stronger and stronger (7). This shows his autonomy and independence in making his own informed decisions unlike the likes of Cromwell and Richard Rich who act as the King’s â€Å"yes men† doing all his bidding. Cromwell, the king’s intimate, works for the king to have More falsely persecuted and beheaded. We will develop here three main kind of adversities that More had to face: authoritarian, Family, himself. Sir Thomas More’s strong character and moral integrity are alluded to by the title of the play, A Man for all Seasons. The title is a reference to More’s never changing character and direction in life. According to Miller, More was a character with extraordinary blending of gaiety and gravity and for his flexible adaptation to company of all sorts. However, he knew how to compromise and not go out of his way; he did not bend rules, adopt or change for the sake of anyone, even King Henry VIII apart from his own God (26-27). This statement concisely puts down his beliefs and what kind of person he was. Thomas works within the boundaries of his own principles and in the end, dies for what he believes in. Lee compares Sir Thomas More with Roper. At the beginning of the play when the two of them are talking, Roper seems really devoted to his principles but as the play continues on, we learn that Roper is in fact not as true to his values as Sir Thomas More is. Lee talks about the â€Å"Romanticized† vision of a prison that Roper has compare to the reality of what More is living. When Roper visited More in prison he even encouraged More to give up when he saw the â€Å"awfulness of prison†. (319). His obstinate sense of self -righteous and defense for justice sees him earn many foes and adversaries. Just like Roper, many people pretending to be More’s friends turned out to become his enemies plotting behind his back for his downfall. His family, friends, and colleagues turn their back on him, and the adversaries from both his seniors and juniors continue swelling. The following are some of the most significant and outstanding adversaries Judge Sir Thomas More earns himself and faces off with. His many adversaries rise from his strong stands and refusal to bow down to the social order. His main and most prominent adversaries are the authorities and technocrats in the country. Upon meeting with Cardinal Wosley, then the Lord Chancellor of England; Thomas More reviews the decision by King Henry to divorce his wife Catherine and marry Anne and the subsequent decisions. He states his disapproval and says he doubts the Pope will give his assent on this divorce as it is confirmed by Greene when he describes the King’s feeling about the decision of Rome as ‘Frustrated’. The king was very disappointed with the decision of the Clergy and Henry vainly sought to increase the pressure on Rome. When that failed, Henry began to target the English Clergy. (7) It is from this particular point that Wosley declares a witch hunt on the judge, having him investigated and falsely accused of receiving bribes, and insult towards the King. These represent the authoritarian adversary, the adversaries that Sir Thomas More has to face that hold the keys of the government and have power and authority to hurt him according to the law. Although they are not following the law when they persecute him, they pretend to do so. The other adversary in the authority level that Sir Thomas encounters is King Henry VIII’s closest confidant, the recently promoted cardinal secretary, Cromwell. He is used by King Henry as a tool to fight and suppress Sir Thomas due to his stand against the King’s planned divorce. Here we are going to see the kind of adversity that was apply to More by his so-called friends in their thirst for power, they did not hesitate to step over him on their ascension to power. Cromwell plans for Thomas’ downfall by collaborating with the corruptible Richard Rich who is a low ranking functional authority. Cromwell offers Richard an opportunity to advance his career and climb the social ladder in exchange for information about Thomas and testifying falsely against him. Cromwell goes ahead and come up with a false case of how Sir Thomas received a bribe and brings to evidence: the silver cup that Sir Thomas gave Rich. At this point as readers we are already amazingly disgusted by the machinery these two people are putting together to get Sir Thomas More down. Eventually, this leads to the conviction and beheading of Thomas. On this matter, Abraham Lincoln said: â€Å"Nearly all men can stand adversity, but if you want to test a man’s character, give him power†. Rich was a good men, probably able to stand adversity with a good self-esteem, but when power was proposed to him, he gave up his conviction. The trut however, is that Thomas received the silver cup oblivious that it was a bribe. Yet, on realizing, he gave the cup to Richard as he did not want anything to do with it. Cromwell, goes ahead to meet with the Duke of Norfolk, another supposed friend, to get him to fix More in a bad light concerning the bribery scheme. The duke, however, proves to him that silver cup, in fact, was passed on by the judge as soon as he realized it was a bribe. Cromwell insists that the duke cooperates and participates in the grand scheme to bring Thomas down. This is because King Henry expects the duke of Norfolk to fully participate in the persecution of Thomas. Thomas woes continue pilling up when Signor Chapuys turns against him and joins the witch hunt. Signor Chapuys’ adversary towards Thomas arises from the breaking of the illusion that Chapuys was under concerning Thomas’ friendship towards the Spanish. Cengage Learning explains the relationship on Sir Thomas More with Chapuys as follow: In speaking with More, Chapuys tries to hide his true motives which are political, with flattery and references to religion. Because he is devious himself, he hears hidden meanings in what More says which leads to misunderstanding. 14) This quote explains why Chapuys did not understand More. He was trying to prove that More aleegiance to spain was no longer and so Chapuys thought that he had found an ally in Thomas to protect the interest of Catherine of whom he was cautious and concerned that she is embarrassed or insulted by King Henry as she is the aunt of the king of Spain. The Spanish ambassador states that he was unsuccessful in per suading More to support Spain saying, as it is affirmed by the sentence Chapuys uses in the play when he says, â€Å"Goodness can be difficulty† (Bolt, 62). Thomas’ refusal to accept the letter of appreciation that is sent by the King of Spain is also a possible source of the aggravated hostility from the Spanish diplomat, Signor Chapuys. All of these men are complotting against someone they knew, someone they worked with, and for some of them someone they had a close relationship with. Adversity can come from authority, friends and sometimes both. The other adversary of Thomas is King Henry VIII who is Thomas’ friend and King.. The king desires to get a son as the heir that his wife Catherine has not borne. He, therefore, plans to get a second wife to fulfill this, and it is here he seeks the support of the lord chancellor of England, Sir Thomas More. More is a devout Christian, and of strong moral standing; hence, he does not approve of this. Although he does not publicly or openly voice his displeasure, he is silently opposed to this. Johnson explains that it is probably to protect his family the best he can that he acts like that, â€Å"He is well aware of dangers on the horizon but does not want to cause them to worry by addressing the dangers directly. 7) At first, More enjoys a somewhat ‘safe zone; by remaining silent about the King’s plans. This comfort zone is trespassed when the King demands the vocal support of the wise, respect public figure. When the King visits him at Chelsea home, in London, More tells the king he will not agree to his plan. The King storms out in anger telling More that he will only leave him alone if he does not openly voice his disagreemen t for his planned divorce of Catherine and marriage to Anne Boleyn. This aggravates and worsens their relationship, which had been set on the rocks earlier. This was when Thomas More had declared he was going to resign if the Church of England Bishops were going to go along with the Parliament’s Act of Supremacy. This Notorious act puts the King as the absolute head of the Church of England, as well as the overall ruler of England State: the genesis of their conflict. This hostility towards the Judge comes to a boiling point where he flatly refuses to take an oath of allegiance in the King’s name, another creation of the King’s puppet parliament. Boughey posits that, â€Å"Henry VIII Wanted to look powerful and strong. [†¦] Henry VIII was a powerful king who was completely in charge of England. Nobody was stronger than Henry VIII, not even Parliament. (1). This is how the king was perceived in real life, probably it was the reason why he was described like that in the play and Sir Thomas More was described then stronger than the parliament and stronger than the King. This is the proof that Thomas More stood strong against the adversity even when it was his King and friend. This adversity can represent a symbol between the King and More with the king symbolically representing the monarchial absolute power and More representing civil law. Thomas’ refuses to have the King rule even his conscience. As a result, he is ready and willing to keep his honesty at all costs, even if it means losing his life. Kincaid expresses Thomas More’s willingness to die for his principles in this little paragraph: When More’s wife was sent to prison to visit him in the hope that she would persuade him to sign the Oath, she told him that he might, if he signit, have another twenty years of life. More answered with his usual wit that if she had offered him a thousand years, he might have been tempted, but twenty years in exchange for an eternity of damnation was a very poor bargain. (9). The kings tries to give More a chance but he refuses and choses to remain faithful to his principles. Thus, coming back to our symbolism, the civil law win over the absolute power meaning that absolute power in one’s hand can be lethal. Thomas’ ethics and integrity is based on a strong base. In the play, other characters appear to be good people but do not have as strong a base as the Judge. The duke of Norfolk for example seem to be a good guy. However, he does not understand More’s motivation. As Lee puts it, â€Å" The behavior of the duke of Norfolk are dictated by yet another good, the benefit of friends. The constant for Norfolk is the preservation of friendship with the people of the here and now, and thus, he cannot comprehend more’s insistence on risking those friendships for his love of a heavenly God. (313).

Economic Releases And Resulting Market Reactions - 1673 Words

Economic Releases and Resulting Market Reactions Introduction Many economic indicators and surveys are made public and reported on the news each week. The economic surveys are so many, and the data usually make very small changes that it is easy to fail to notice the importance that this data has on the economy and the markets. There are various indicators that help one to understand the dynamics of the economy. Knowing the market indicators and keeping tabs on the economic releases helps interested parties to be better prepared to foresee and respond to future market developments. They include; employment, investment, consumer activity, and inflation. For the purpose of this report, only employment and investor activity is briefly explained in this introduction section. Employment, which will be analyzed extensively in this report, is probably the most important indicator of the economy s health. The United States Bureau of Labor and Statistics releases a monthly unemployment report and the nonfarm payroll on the first Friday of each month. The unemployment report shows the latest unemployment rate. The nonfarm payroll shows the number of jobs that have been gained or lost in the United States economy. Participants in the market keenly look out for these reports and the usually result in the major one-day movements in the stock and bond markets. The employment situation influences other important economic indicators, for example, consumer attitudes and consumer confidence.Show MoreRelatedA Look At The Problem794 Words   |  4 Pagesproblem On further analysis, the book makes it apparent that there is an inherent tendency towards individual gains over the health of the market. As a result, it is easy for big business to direct their resources towards frustrating the efforts of their smaller compatriots in a bid to secure profits. 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