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https://designers-guide.org/forum/YaBB.pl Simulators >> Circuit Simulators >> OpAmp simulation https://designers-guide.org/forum/YaBB.pl?num=1175289805 Message started by eng on Mar 30th, 2007, 2:23pm |
Title: OpAmp simulation Post by eng on Mar 30th, 2007, 2:23pm Hi I'm a designing a fully differential opamp for CT Filter. The circuit has different gain and phase margin values according to the analysis I chose. Case 1: XF analysis. 1 Port element connected between diff input and biasing voltages are applied thru a AC blocking resistors (50K). Gain and phase curve drawn at the output. Case 2: AC analysis. Common mode (vdc) and diff mode (vsin) sources connected thru an ideal_balun (from analog lib). Gain and phase curve of (vop-von)/(vip-vin) are drawn. There is 6 dB gain difference and 80 degree phase difference between 2 simulations. (XF has better results) I wonder if there is any trick that I'm missing in the setup and which case is more proper for and OpAmp simulation? Any helps will be highly appreciated. |
Title: Re: OpAmp simulation Post by Ken Kundert on Mar 30th, 2007, 3:21pm The port component is giving you twice the voltage you think it is because it is not seeing a matched load. You should use the voltage source setup. -Ken |
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