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73 Threads found on edaboard.com: Design Folded Cascode Opamp
Hello everyone, I have been facing problem in designing a folded cascode CMOS opamp. I have designed the mosfets aspect ratios for the amplifier circuit but i could not design the bias circuit. I admit i am not very good at designing circuits. so can people here help me (...)
I need folded cascode design step by step, i want to implement it on cadence 180nm suggest me the procedure or ieee paper through which I can design folded cascode opamp using cadence
Hi All, I have a student project "design a high-voltage CMOS opamp", and I have two questions: Wich architecture is better for high voltage opamp (Voltage range 50-110 V) and why? If you have a papers or books related to my topic, please give a link. Thanks in advance, Vadim
can somebody plzz tell me what actually affects the gain of folded cascode operational amplifier..... n how to increase the gain of folded cascode aoperational amplifier...???????
Hi Jyotimaya You can follow this link to design your opamp - - - Updated - - - Hi Jyotimaya The previous link help you to design single output first after you have done it , here is differential output with cmfb and bias file
Hi, Can you guys please help me with designing the bias circuit for the fully diff folded cascode opamp (attached) i.e., to generate the bias voltages Vb1, Vb2, Vb3. 108205 I tried to search in many books, but none seem to explain properly the biasing schemes that can be used. Any reference to relat
Hi, I am designing an 10 Bit 200 MSPS Pipeline ADC in TSMC 65nm process. Just finished the design of first stage opamp. It uses the "folded cascode Gain Boosted opamp" architecture. The supply voltage is 3.3V. The total current drawn from the supply is around 90mA. Therefore, the first (...)
Though i did not design the LDO for your specs..but the structure on CMOS may look something like shown in figures attached. I used folded cascode opamp for error amplifier with output stage W/L chosen for 10mA output current. My supply voltage varies from 3.2V to 4.2V. obrazki
Hi, I have designed a folded cascode two stage opamp on 130nm process. The opamp works fine. Figure below shows the gain and phase response of opamp. It has 45 degree phase margin. Now the next step is to design circuit which generated the bias voltages for (...)
Hi, I designed a folded cascode opamp with gain boosting and it works properly, now I want to design biasing voltages of the opamp. I could design a biasing circuitry for the main opamp, but I had a hard time finding a way to generate the dc voltages that (...)
hello frnds, i am designing folded cascode opamp. For analysis purpose i need source code for ICMR,Offset voltage, PSRR, noise margin. i am using tanner tool. i.e TSpice analysis code is required. i find gain of my design is 170dB. so, i am doubting on my design. thanks, Prati
Hi I wanna design an opamp (2 stage folded cascode) where can I find analysis of this opamp? I need to know poles,zeros,unity gain,... for designing? plz help me I wasnt able to find any book or paper.:cry::cry: tnx
I am designing a folded cascode opamp with a single-ended output and that has both NMOS and PMOS input differential stages (for wide input common mode range). All the circuits I see, however, have a differential output. Is the bottom design a correct implementation of a single-ended
I am suppose to design a folded cascode opamp with considerable gain and high bandwidth with low power. (1.2V and 300uA total current). I am new to designing. Kindly anyone suggest me some papers or materials or books on the folded cascode design procedure.
i think y should refer to chapter 9 of professor razavi's book (design of analog cmos integrated circuit).y will get the basic benefit of ICMR
Its an integrated circuit design. I am using a folded cascode, and I use Cadence Spectre to do the trasient analysis.
Hi, With only 5uA current, I believe your bandgap wont drive large RES/CAP load. So either two stage miller opamp or folded cascode opamp should be OK Come on! design it first.
David M. Binkley "Tradeoffs and Optimization in Analog CMOS design" Chap. 5.2.2 cascoded OTAs: design descriptions for two cascode OTAs with 2 different power consumption vs. GBP flavors in a 0.18?m CMOS process.
u should be able to hit 70dB gain easily using folded cascode design.... 46dB sound likeu dont have transistors biased correctly. use 5-10 times minimum length for current sources/rail devices and 2-3 times minimum L for your cascodes. this will give u good output impedance.
I am trying to design an op-amp with rail to rail inputs and am finding an issue with the symmetric input stage trick. I am limited to a process with no floating gate and nothing fancy like triple well. I have tried two approaches, one with a simple dual (symmetric) nmos and pmos differential pair and also with a dual folded cascode (...)
I'm designing an opamp and need 78 dB gain and 4 GHz BW with 3.5 pF Cload and 2.5 V supply voltage. I can get the gain with a single stage folded-cascode opamp, but the best result for the BW is just 1.8 GHz. Would you please let me know your opinion about this design and any suggestions for (...)
I have got the phase value at 0db gain is -74deg so my phase margin is 180-74=106 or 180+74=254 which one is correct or is there any error in design ?
I have to design two opamp's in cadence that i will be using in my masters project(16 bit Delta sigma ADC) in 90nm\displaystyle far as i know till now, opamp's used in converters should be Low i/p noise, faster settling and High GainBandwidth product, Low offset voltage....are there any more considerations to be considered while (...)
Hi I am trying to design the fully differential folded cascode opamp on page 387 of Book CMOS analog circuit design by Allen Holberg. I designed the differetila input to single ended output first which gave me a verrryyy less gain. Could anyone please helkp me in figuring out a way to (...)
I have designed a folded cascode opamp.... so if i connect a feedback resistance and an input resistance to the inverting terminal, will it act like an inverting amplifier.....
HI GUYS I AM designING folded cascode opamp FOR SWITCHED CAPACITOR APPLICATIONS I AM FACING FOLLOWING PROBLEMS 1) BIASING THE PMOS M18 AND M10 WHAT SHOULD BE THE CIRCUTARY FOR BIASING IT OR WAT I HAV DON IS CORRECT THE CASE FOR NMOS M23 ,M24 TOO ( CHECK ATTACHMENT FOR PIC OF design ) 2) NO PMOS (...)
in two stage opamp, such as telescopic + common source (as the figure shows), or folded cascode + common source, with cascode or improved cascode compensation, how to improve the PM of the opamp? first, how to decide the bias voltage for the opamp? assuming that the (...)
Hi everyone, i am designing the Band gap reference in which it requres op-amp(i am using folded cascode op-amp). My VBG voltage is 1.25V. My question is 1. How to decide/choose pmos tail current in opamp. folded cascode op-amp is given
I was trying to design a common mode pipelined ADC? I am designing for 20MSPS and 10 bit. I have already designed a folded cascode opamp with a gain of 56dB and Unity Gain Bandwidth 600Mhz. My settling time is 18 ns. I am using a common mode design(not differential) (...)
with a carefully designed 1-stage folded cascode, you can achieve about 70-75dB (not far from what you need) and you could use gain boosting to gain some margin. In this case you have the advantage that you need no compensation. If you want to design a 2-stage opamp, try to read "An improved frequency (...)
i want to design a two-stage opamp with cascode compensation ,and the first stage is folded cascode structure, the requirements as follows: resolution:11 bit clock speed: 20M CL=2pF,Cs=Cf=1pF,DR=70dB,Vdd=3.3V,output swing= +/-1V then how to design the two-stage opamp (...)
Dear all member, I design 1.5 bit MDAC,: using gain boosting folded cascode opamp DC gain : 80 dB UGB : 100MHz but after I set it up with sc circuit, (2 precission multiply ) I can't get the rsult, sometimes output is bigger 1. ... Vin but sometimes output even smaller than input. do anybody knows (...)
Hi, I am to start a new layout on a 15 stage pipelined ADC. What are the specific layout considerations for the same? The design is of a folded cascode opamp, switch cap architecture, a feedback stage. Thanks, vijay
Dear All : No I work in Delta-Sigma DAC design , I need a good opamp (single-end ) for the low pass filter design, I read some paper , It need High DC gain about 90dB , Unit-Gain Bw is large 75MHz, The Noise is about 2~3 uVrms (20~20KHz). Does anyone work in this filed, And good OP Structure can share it , Thanks
I successfully completed the classic 2 stage opamp design with Miller compensation, and am looking at advanced Op Amp designs. I started with folded cascode opamp design and am in a confusion not knowing where to start. I went through Johns Martin, and Jacob Baker's (...)
Hi I'm a beginner and I want to design a folded-cascode opamp,my question is,in order to have a large output swing (as much as i can) is better a single-ended or a differential output, I'd be glad if you can tell me what kind of trade-offs I have to deal with.
i m working on cascoded op-amp...... i know the value of Gm of transistor for mentor tool if i want to work on pspice will its value gets changed?
what are the specifications of op amp in R2R Ladder DAC? and what is the best method to design that op amp? folded cascode?
hi, i need a low power rail to rail opamp with max 200 MHZ BW. i work in 0.35um and simulate with HSPICE 49 level CMOS. let design it. thanks.
Check chapter 8 "fully differential amplifiers" in "Analog design Essentials" by Willy Sansen. It is a very practical oriented book, and I recommend it highly.
What is a good structure for the opamp used in a switched-capacitor integrator? I've seen that folded-cascode and class AB opamps are so common. But for a low-voltage and low-power design, what are the benefits and drawbacks of the two structures? Do you recommend any other structure(s)? Why? Thanks.
hi friends, can anyone give me design procedure of fully diff folded cascode opamp structure? any document plzz.. thanx
Hi everybody, i am going to design folded cascode with gain boosting opamp, so ihave to design op amp with pmos differential pair to boost the gain of NOMS, and design opamp with Nmos deferential pair to boost the gain of POMS. the question is i can use the same bias (...)
Hello Friends... Which opamp topologies is best suitable for a switched capacitor filter design. Should i consider telescopic or folded cascode topology(both for Fully Differential & Single ended)..? basic specifications are gain greater than 65 dB, UGB greater than 300MHz and Phase margin about (...)
Hi, all, I need to design an CMOS op amp, the maximum loading is 300nF cap. Supply is 5V, slew rate is 5V/1mS, bandwidth is 100kHz. What kind of structure and compensation scheme can do this? Thanks tia
so you already designed your first stage and knows the closed loop BW is. The second stage current mainly servese you two things: 1. Provide gm2 to set your 2nd pole. 2. Provide charginig/discharging current. (Slew Rate concern) Based on the above two critireas, you can claculate your 2nd stage current. Tail current means the first stage c
Generally, the two stage opamp maybe need compensation, because it has two high-impedance nodes as naalald said, and the folded cascode opamp does not , may be the book design essential> written by W.Sansen will be better for you to study
I believe you can easily design a folded cascode opamp with a gain of more than 70dB. Create a two stage opamp, which are folded cascode as a first stage and followed by another common source stage which will total up your gain up to 80dB. So, you no need to worry on the (...)
How to decide the current bias of input stage and output stage of folded cascoded opamp? In some text books which suggest us to use larger current for input stage to boost gm, and use less current for output stage to increase ro. But, I got a problem, the opamp linearity is poor in higher frequency opeartion if I do so. (...)
Hi, by using any ordinary two stage opamp, you can design it easily. If you want an example, u can see the allen-holberg book. They gave very nice example for beginners in the "opamp" chapter. u can follow the test circuits given there, to check your specifications