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# Op Amp Pspice

55 Threads found on edaboard.com: Op Amp Pspice

## Simulating 741 Op Amp

I am trying to simulate the op-amp schematic diagram for a 741 and plot a graph of Power Supply Rejection Ratio v frequency. It is defined as 20 *log( change in dc supply voltage/ change in input offset voltage). Does anyone know how to work this out on the Cadence/ pspice simulator? Do the 2 differential input voltage sources need to be removed a

## Calculating PSRR for 741 Op-AMp

Does anyone know how to evaluate the PSRR of an op-amp practically on a simulator like pspice or Cadence? PSRR=20*log(change in supply voltage/ change in input offset voltage) How do I calculate the input offset voltage? Do the 2 differential inputs of the input stage need to be grounded to evaluate the output offset?

## Help me to find out cut-off frequency and gain of Op-Amp LPF

Try to sweep in frequency from 0 to 100kHz and obtain both gain and cut-off frequency. Cut-off frequency is no magic number. We agreed it is 3dB. You can try in Spice or you can try to sweep in frequency in hardware. I in school have a VI (in LabVIEW) which I can sweep in frequency the function generator any kind of wave. Makes things easier

## How to simulate an active Op-amp filter?

I have a circuit diagram that is an active Op-amp low pass filter , but i don't know how to do the simulation of its frequency response using pspice. Can someone teach me??? Thanks Use an sin input signal and ac amplitude) and measure ouputsignal => bode plot

## How to simulate a current to voltage op-amp with Pspice

hello Clansman There is an element known as a current to voltage convertor in any version of spice. please kindly refer to the following page to know how to use it in your simulation. You can maybe add a low pass RC network to the output to model the single pole roll-off frequency response of an I to V or rather a transimpedance op-amp! htt

can I design high speed op-amp on orcad if yes plz,illustrate how to get cmos models of orcad and how to design if not which tool i can use

## Resistor, capacitor and op amp model?

Can anyone suggest what model of resistor, capacitor and op-amp to use in pspice for me to simulate under military temperature range(-55degree C to 150degree C )? I need model which can vary according to temperature in pspice. Thanks.

## How to find output voltage swing of fully differential op-amp?

help....how to find output voltage swing of fully differential op-amp

## Max peak to peak output for bi-polar op amp

I've designed the attached bi-polar op amp. How do I calculate the max peak to peak output swing and max peak to peak input before distortion? Thanks

## Op amp GBW= 6.28 MHz in PSPICE, looking for one

I'm doing a lab for my class and it says to look for an op amp with a GBW of 2*pi*10^6 = 6.28 MHz. I've been looking for an op amp with that spec in the pspice library but still haven't found one. Does anyone know if pspice has an op amp like that or how I can easily search the pspice (...)

## Question regarding Laplace and Op-Amp

Hi guys, Right now I've a Laplace ABM-Filter(PI Filter) in my pspice Simulation. I want to replace the Laplace ABM-Filter with a real OP-amp. My question is, will the Vcc+ and Vcc- of the Op-amp influence my result?

## simulate 741 op amp is spice

Hi yes I want to simiulate the internal circuit of 741 op amp. but I don't know which specifications for transistors shoulde be used? I use some kinde of transistor which is in pspice simulator, but the bias point of op amp doesn't work properly.for example current mirrror dosen't mirror current properly!!

## LDO Regulator, OP-AMP noise model in the time domain

Hello, Currently I'm working on the LDO reg. pspice macromodel but I have some concerns about the output noise modelling. After studying some papers on Op-amp macromodels I was able to obtain fairly good match between the Output Voltage Noise Density Measurements and Simulations in 10Hz-1MHz bandwidth. (The noise source was placed in series wi

## About designing an op-amp circuit where Vout will be the root of input voltage.

please some one tell me the logic of designing a simple op-amp circuit in pspice. where the output voltage will be the square root of input voltage

## Op-Amp thermal drift PSPICE

Hello, how would be the method to simulate the thermal drift in an op-amp with the SPICE macromodel? I pretend to simulate the -40 to 85 ?C behaviour of the circuit and i think the op-amp macromodel doesnt have any parameter dependant with the temperature.

## How to build a PSPICE library for an opamp ?

Hi, Why don't you give the part number of the opamp you want to simulate ? There is a lot of free available models on opamp provider's site. If you cannot find it on those sites, maybe someone has it and can give it to for free. Just give the part number and someone will help you.

## What is the macro model of opamp and comprator in Pspice?

when I simulate a circuit by using pspice. How can I use a behavior part to act as an op-amp or comprator?

## Making a Pspice model from a .mod file

1) Go to 2) Under the heading LMH OrCAD Library You will see schematic symbols of the op amp. All files are contained in one ZIP file. Download LMH OrCAD Lirary (10k PKZIP file) If this does not help you PM me.

## How does Ideal Op-amp behave?

try putting some load at the output of the amplifier. The 741 output has a path to ground where as the ideal opamp otuput does not.

## spwm and comparator problem usind pspice.

hello. i'm trying to simulate ,on pspice, the control circuit of 6 MOSFETs in a dc /ac inverter. i want to use spwm for the switching, so i put a comparator(lm339/lm393). a triangular waveform goes to the inverting input, and a sin wave goes to the non-inverting input of the op-amp. the op-amp gets supplied with +10V in the +pin and 0V in (...)

## cannot find pspice model in the manufacturer webpage

Hi. I've been searching and searching on the TI webpage for the LM2904P I can download the symbol but it doesn't come with the pspice model does it? It's just a general purpose op amp and is suppose to be relatively simple says my lecturer but it's driving me nuts! I downloaded the TI

## PSPICE Simulation for a PI Control circuit

Hi all, I wanted to check the stability of a PI control loop as in attachment. In circuit, I used the simplest model of OP-amp, which has rails of +5V and ground, and the open loop voltage gain is 1e+6. It is an idealized OP-amp model as an accessory in ORCAD, since I am insterested in the general concept of the control loop rather than some specif

## OrCad PSPICE simulation problem, MC33701

Hi all, I am trying to simulate a circuit with an op-amp from OnSemi. On their website, they provided a model for this part (MC33701). This model is in .ckt format. Can anyone explain to me how to use this .ckt file in my design to simulate it? I've tried several steps that I usually do when I have to import a model from supplier, but for

## LIB & OLB for Orcad Capture 16.2

Hi all. I designed an Op-amp in Orcad Capture 16.2 with MOSFET transistors, and wanna test it with a technology file. no matter its 0.18um or .35um or others. and no matter from which company. just i want a 'lib' file, to use it in capture. I can create 'Olb' file for it, myself. I tried with .L and .lib files that originally used for Hspice but

## Triangular waveform generator in PSPICE

Bot OPs have +ve and -ve input mixed up.

## Simiulate 741OP-AMP in spice

I want to simiulate 741 OP-amp with pspice. But there was a problem that circuit too large! What can I do? Can I simiulate this in Spice?

## Reducing op amp ring when charging capacitor

I have some doubts if the Falstad simulator represents the OP behaviour accurately in this situation, the pspice models usually do. The basic problem is simple, zero respectively negative phase margin in the loop gain characteristic. If the OP compensation isn't accessible for modifications, you have basically two option: - an output series

## PWM Control of dc converters

get the full version - you must be running the trial or student version limited to 25 or something transistors. FYI - no i don't have the full version for you to download, plz don't even ask. but... if you really want to build pwm, i can help. Sawtooth wave + Error voltage => PWM You could do that with 1 VPULSE source, 1 VDC, 1

## How to simulate the input-referred noise voltage of an amp?

Just add a ac sweep and a noise analysis statement. This is an example for hspice: .include 'opamp.sp' .global vdd vss x1 vp vn out opamp vdd vdd 0 10 vss vss 0 -10 vp vp 0 0 ac 1 0 vn vn 0 0 .op .option dec 10 1 1e+9 .noise v(out) vp 10 $vp is the refered input .print noise inoise onoise$ ... .end The inoise is the

## Which software can simulate phase shifters?

i want to simulate a phase shifter.which kind of software i need adopt? thanks

## 3.3 V commercial opamp SPICE model

The companies that make op amps also have models on their web sites. You will have to carefully look at the model descriptions. Some are simplified for faster simulations and do not include items such as accurate output signal swing limits, input bias currents, input offset voltages, etc.

that is because you didn't make R1,R2 and U1 connecting properly by wire. suggest you moving them away each others and re-connecting exactly at pin point.

## Saturation and Convergence problem in ideal opamp

Hi I am using an ideal op amp in inverting configuration as shown in figure (in pspice). The output fails to converge when i increase the value of feedback resistor (R2) above 14.5 KOhms The simulator gives the following error: ERROR -- Convergence problem in transient analysis at Time = 708.8E-06 Time step = 582.1E-18, minimum allo

## The method for finding the I/O resistance of 741 opamp

Hey, A very simple way is to stuck the small signal model of BJT, and write some KVL and KCL to get Rin or Rout.. The idea of analysis is to remove all independent sources, put a voltage source with voltage Vx at the node from which you want to see the resistance, try to find Vx/Ix (Ix is the current supplied from or to the source you put) whi

## Genesys Active filter design transfer to ADS not working OK

I made an active op amp low pass filter design in Genesys and exported the design to ADS. When using the design in ADS the filter passband and stopband look like in original design but the insertion loss is more than 240 dB. Has anyone faced this before? I tried to change the port impedances but did not get the same results as in Genesys. Filter l

## FET Based Phase Shift Oscillator

1) You are right. It's a phase shift oscillator. 2) I have no problem with the op-amp one, the problem here is how to see the oscillation results in pspice by using FET?

## How to measure offset and how to reduce it

Can any body suggest me how to measure offset for an opamp (like 741) in pspice. And how it could be reduced. for example putting R instead of active load is helpful? tanks!

## need help for design high bandwidth folded cascode opamp

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?

## simulation of op-amp uA741 in Pspice

hey guys i just wanna ask..i got some questions using pspice to find some practical op-amp limitations with op-amp uA741..the problem is now..i already construct the circuit as given in my tutor..but i didn't get the simulation of this circuit..can u help me? is there anything to do with the specifications of the opamp? or (...)

## Inserting SPICE Netlist in Schematic in CADENCE

Hi, I am using CADENCE AMS, In want to draw a test circuit of an Op amp (AD822). The problem is that I can not insert the AD822 in my circuit or I don'h know how I do this. In the website of Analog Devices I find only a .cir file which describes the equivalent circuit of AD822 (the netlist). I have already used this file in Orcad pspice to sim

## How can calculate the Bandwidth of analog circuit?

I have block diagram from a system and I want to improve bandwidth of system. I know, I must be draw by Orcad or pspice and simulate by Matlab but I don't know how can do it. I also want to know which component is cut off my bandwidth in system which is consisted : Input structure "Op-amp,V-I, MUX(Switch Array), Electrodes", then Output part "Elect

## PAC and AC analysis - request for manual

Hi, I am new in cadance, till now I have used only pspice so sorry for may be stupid question. I make SD ADC so I am designing OP amp for the untegrator. I made AC analysis with continuos CMFB of the amp. In reality amp will operate with SC CMFB. From manuals of Spectre as I understood there is some PAC analysis which (...)

## Software for Analog Simulation - P-SPICE ?

Hi All, I am using OrCAD for Schematic and PCB Designing. But Now I have to learn some Software for Analog Simulation as Below: 1) SCR, TRIAC, DIAC, Power MOSFET, IGBT ( Power Devices 220V to 1000V for both AC and DC) 2) Op-amp, Transistor and FET 3) R,L,C 4) Coils and Transformer Is P-SPICE Help me for that? or any other sof

## Setup to test PM of 2 stage opamp..??

This setup for AC analysis of differential op. amp is not quite correct, because it presumes that input CM is equal to output CM which is not always the case. Instead of that I propose you system using voltage controlled voltage sources. Assume differential op amp with: 1. Input nodes INP and INN. 2. Output nodes OUTP and OUTN. 3. VCM_REF

## Amplifier with supply voltages of 0 and 5 volts.

I'm trying to build a amplifier for a small signal, aound 2.5 volts. Im using the AD8001 op amp. the signal is about 1 MHz, and of a few mvolts so i need a gain of about 40 db. I've buid the circuits a described at the attached file. First i used -5 and 5 volts as supply voltages for a signal around 0 DC. The circuit worked well. But in my ap

## Altium spice model simulation

I have imported LT op amp simulation sub circuit model from LTSpice library (.mod) file. I did it by simply changing ext from .mod to ckt. Altium Accepted this model. However when it came to simulation it looks Altium does not understand SPICE. The line which cause error: ESHD1 88 0 Value={0.5+0.5*TANH(-5*(1.2-V(3,7)))} I finally figured o

## Help designing a filter for a DAC

Okay, I want to add a filter onto the end of this circuit with the transfer function: \frac{1 - 3e^{-sT} + 3e^{-2sT} - e^{-3sT}}{s^{3}T^{3}} (T is the sampling using pspice. The denominator seems simple enough to implement, just 3 op-amp integr

## Help with a circuit.....

Hello,i have this circuit which sources or sinks current and i should control Vin- and Vin+ with a pot with its 2 edges connected to a negative and a possitive power supply respectivelly.First of all i would like someone to explain how this circuit works because i don't really understand and second,can i supply the voltages Vin only from one poten

## Lc meter Oscillator Circuit

The circuit should work fine, oscillating around 500kHz. Try to change the op amp model in your simulator (for example with LT 1260)

## subthreshold squaring circuit

hello everyone, i am persuing my final year project in the subthreshold squaring circuit. i want to simulate differential op amp and current mirror using pspice. can anyone help on it. thank you so much regards, sushant