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1000 Threads found on Opamp Suggestion
A TL081 is good or an NE5534 is even Lower Noise. BOTH of these require +/- supplies. No they don't. ANY opamp can use a single supply if its input is biased at half the supply voltage. Coupling capacitors might be needed.
Hi, I am interested in designing a low power low voltage opamp, can anybody give me any suggestion? Thank in advance.
Look they have something. How they call them: opamp evaluation boards I think. See their application notes which have schematics in them.
I have completed a 2 stage opamp with GBW of 330MHz, DCgain=60dB, GM=20dB and PM=54 degree. I found that i can't go beyond 3rd order unity gain 200MHz SallenKey LowPassFilter since the o/p signal is out of phase. Can anyone give any comment/suggestion/solution? I see 300MHz bandwidth. What opamp did you use?
I have a circuit like in the attachment. What i want to do is adding 2.5V offset to the input signal. But the rms value of the output is a bit lower than input but there is no clamping on the signal. What may be the problem? My 2.5V reference? or other thing. I use this opamp:
How to layout the cascode opamp on RAZAVI'S book ,figure 9.48? Any suggestion? In figure 9.48, (1) put the M1,M2 ,M1P,M2P in the middle of M9 ,M10 ,M3, M4, M5, M6, M7, M8 (2)put the M1, M2 ,M1P,M2P just in the left or right of M3 to M10 which one will be better?
find the document ,which my give u come idea hot to characterise the opamp regards, vijay
Dear all, I need you guys suggestion. What kind of circuit need the higher CMRR or PSRR of an opamp? Plz tell me if you know, thanks!!!
Hwo to bias opamp which is used to force two nodes voltage eaual? If we use PTAT current generated by bandgap core itself, another loop is created. The stability is also a problem? How to bias this opamp?
Hi friends, i have to design an opamp in 130nm umc foundry process.This is going to be used in a dual slope adc for the integrator and comparator part .The inputs to this opamp will be biomedical signals like eeg or ecg which have frequencies like from few hertz to 100-200 hz. The supply voltage is 1.2v and i require a opamp with atleast (...)
Hi, please find below a small example : *Non-Inverting Amplifier .param voffset=0.1 lot=50% r1 5 3 100k r2 5 0 1k c1 3 0 1p yopa opamp2 pin : 2 5 3 0 param: p1=1e3 p2=5e8 gain=5000 voff=voffset vin1 2 0 sin (0 1 100) .tran 0 7 .plot tran v(2) v(3) .option display_carlo .end
Hi, In an opamp, I want to increase the bandwidth without increasing the current. I think I should increase the gm of the output transistors whose drain constitutes the high impedance node of the circuit and the dominant pole. I do so but the bandwidth does not increase. What is wrong with the procedure? Any suggestion? Thanks.
Hi this bandgap the startup circuit works fine untill I apply an offset (vos) to the opamp. With a positive offset, all it's ok but witha negative one the loop becomes open! Why does it happen? Any suggestion to avoid this bad behavior, please? TIA, CBs
Hi I'm designing a telescopic opamp for wimax adc aplication. Important Spec Bandwidth : >> 40Mhz Gain : 50dB PM : 60 70 degree I have no problem getting the gain and the PM...but to get the 40MHz bandwidth quite a problem. All calculation are done user 1st order formula....Can help me with more accurate calculation. My model use Bs
If you are worried that the opamp amplifies its input bias current in the resistors then seleect an opamp with Jfet inputs because it has no input bias current.
Hi, I ve created a Pspice schematics of a 3 opamp instrumentation amplifier. I need to plot the CMRR for the there any direct way to plot the same ie CMRR Versus Frequency.?
Dear ALL, My question is centered on ADC's of microprocessors connected to sensors via ADC's. When do we need an opamp? and Why do we need it, is it a buffer? let's say I have a PIC or 8051 microcontroller ADC connected to a sensor that needs opamp, what opamps are suitable? Best Regards, Basel
Hello, I was wondering if it is feasible to build a 741 opamp out of discrete components. The internal schematic is clear and no double emitter transistors used. What I need is a suggestion for the transistors that could be used. (this will be used in a sweep circuit)
What is the high level of step impulse for testing slew rate of an opamp? Unity gain topology, supply 1.8V. May I put step from 0V to 1.8V with rise edge of 1ps, or there is some way to exactly calculate levels?
I want to calculate the gain In your circuit, gain=1 , due to full negative feedback. If you want to measure gain & phase vs. frequency, use your opamp in open loop configuration. There are a lot of threads about this in the forum. E.g. search for "Middlebrook" .
Anytime I read something like the header "opamp behaves strangely" I first look at the power supply - and very often single supply is used without knowing the consequences (proper biasing).
Hi, I want to ask all the analog ASIC designers here if they have some nice formular collection and cookbooklike papers how to design different flavors of opamps (from 2-stage till full-swing class ab outputs). I know the book from holberg and gregorian - what i'm looking for is more complete formular collection (for example also for class ab am
links to some useful documents here:
Hi all, I'm new in linux, I'm looking for some way to share file between linux and win2k machine. I have try the NFS but the effect is not good enough. Because the file share from win's machine to linux and the owner belong to root. Therefore, other users can goto edit or create file inside the shared directory. Anyone have any suggestion to me.
Hello, I will check the dac and opamps today. In my little project user will use always these 9 switches like that first switch group will push the user to select one of these 3D, 4D, 5D second switch group will push the user to select one of these 8Kv- 14Kv- 16Kv and so on totally there will be 9 switch and operator will use these switches to
Calculate opamp
Hi opamp: Globally Optimal CMOS Analog Circuits 1. -> t tnx
Un-believable, but it is true after the measurement ! See attached, it is the rail to rail IN/OUT opamp from SEIKOII. points are: 1. 0.9V~5.5V working voltage 2. 0.5uA supply current even on 1/2 Vsupply output (unity gain) and even for 5V supply 3. several mA output capability 4. Only one pole for bandwidth response Any idea to make such
8) This is a free IP, I want use it in our SOC design, who used it before? give me some suggestion or help. The leon processor site:
anyone knows this 8pin DIP IC : 5220 I suppose it is opamp of Mitsubi*shi but I am not sure.... It is placed in a preamplifier of Kawai... regards
Hi Does someone have any suggestion for digital watermark using FPGA? I am first time to touch this project. I have no idea how to start. :(
How to measure an opamp's noise charaeterization?
Make sure to bias the opamp. Also, you should put it in DC closed loop. This is done by connecting a huge inductor 10e10) between its output and the minus input with a huge (capacitor 10e10) between the minus input and ground. Then, you can apply the AC signal (with a proper DC value) to the plus input. Feel free to ask again
Hi everybody, I got a problem recently that I don't know how to solve it. I really appreciate your helps and comments on that: problem is: I have layouted a two stage opamp with switched cap CMFB. The opamp works fine in schematic,the extracted file including parasitic C also works very well but if I include parasitic R, it doesn't work and the p
Consider that 741 was the first internally compensated monolithic opamp. Its 30 pF compensation capacitor (making the OA stable at unity gain) ocuped a big area in the chip and was a technological innovation. Z
In can find a PhD thesis named "Circuit Techniques for Low-Voltage and High-Speed A/D Converters" where, among other things, switched opamps are discussed. Hope this helps
if u r looking for a low voltage low power opamp use lm358! BEST!
Dear all, I am doing a research on the opamp pole/zero design, would somebody provide me some info abouth this topic? Paper or thesis ... All are welcome! Thanks a lot! :P
i'am using an opamp operating with vdd=2v and VSS=-2V ..iam using swithched capacitor technique to realize a multiply by 2 operation..if my input voltage is 2v ..can the output(2v*2) reach 4v.
In the full differential opamp,the common mode signal detector is formed with two resistors in parallel with two capacitors in most cases. What's the function of the capacitors? What will happen without the capacitors?
if u mean a current transformer, then u must term it with a load and measure its output voltage. if u mean measuring outout currrent of a transformer, then use a shunt resistor and then measure its voltage drop. if u need a current comparator use a current to voltage converter (like an opamp + a negative feedbak with a resistor) and then use a co
It all depend on the specification that you are looking for. Most of the time the process we use to design a opamp will be the crucial point as it will limit the design parameters and the rest as others mentioned in the post.
How can I determine the dominant pole of an opamp by hand calculation? I am confused with associating each node with a time constant and things like that......where can I find good reference about that? I read Razavi's simply does all the calculation and I don't really get any insight of the circuits......any idea? Thanks a lot. :D
Hi, every one, I am pretty new here. I just start my study in RF mems area. Last semester, I took RF course which was taught by a very bad teacher. I don't think I learned a lot from his course. Is there any good books, simple but have some depth, for RF or RF mems? Any reply will be highly appreciated. Thank you guys. Alekhsei
Hi, What things should be considered when design audio codec with sigma delta ADC ? What is the requirement of the opamp for example ? thanks vita
Hi, opamp is in theory used as a summer and any imperfection in that is added to the input each time and cannot be removed by the LPF. B R M
opamp is the amplifier that has the characteristic close to the ideal amplifier. The ideal amplifier has infinite gain, infinite input impedance and zero output impedance.
Hollo! I am design a Piepelined ADC now, and I need a fully differential opamp. But I donot how to measure the parameter of fully opamp!! such as S.R , Outputswing, ...etc.
I need to design a telescopic diffrential output opamp for different input common mode and output common mode voltages. say, the input common mode is 1.25V and the output common mode is 1.65V. When the opamp is connected in feedback. do I need a level shifter to bring down the 1.65V to 1.25V at the opamp input pairs. Since the (...)
I think that OTA has high output resistant and opamp has low output resistant Comparator is a nonlinear circuit, it may care more resolution , but opamp should care for linearity, and opamp are used in feedback loop so we also need to pay more attention to stability in opamp design