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The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl Simulators >> RF Simulators >> Class B RF Power Amplifier ,IIP3/OIP3 Spectre https://designers-guide.org/forum/YaBB.pl?num=1277203226 Message started by purplewolf on Jun 22nd, 2010, 3:40am |
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Title: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 22nd, 2010, 3:40am Hello, I am trying to simulate the OIP3/IIP3 of class B RF power amplifier using Cadence Spectre .. I have tried the following analysis 1)QPSS with one large and one moderate tone 2)PSS with two large tones 3)PAC +PSS I sweep the input power from -60dbm to 30 dbm whereas my amplifier inout referred one db (Pin 1dB) is at 20 dbm. So, according to theory my IIP3 must be 20+9.6 or greater than that factor but I am getting IIP3 of 14 dBm ??? Secondly , does large signal means that Spectre analysis the circuit interms of harmonic balance techniques(strongly non-linear) while moderate or small signal means analysis interms of volterra series expansion (weakly non-linear).. Do i need to provide different power levels if i choose one tone as large while other as moderate?? What exactly IIP3 OIP3 means in terms of class-B power amplifies? Does the theory in books regrding LNA,Mixer IM products apply here? I have tried every possible way to solve this issue and searched lots of forums and manuals but dont know how to fix it?? |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 22nd, 2010, 4:09am Are your questions focusing on very specific vendor's simulator, Cadence Spectre ? If so, post to simulator's board not design's board. purplewolf wrote on Jun 22nd, 2010, 3:40am:
Class-B Push-Pull using 180deg-Hybrid or transformer ? If so, your result of IIP3 is relative reasonable, since 20+9.6-12=17.6dBm is close to 14dBm. purplewolf wrote on Jun 22nd, 2010, 3:40am:
And small signal in PSS/PAC or QPSS/QPAC is pure linear analysis around periodical or quasi-periodical steady state operation points. purplewolf wrote on Jun 22nd, 2010, 3:40am:
But valid signal level for small signal in PSS/PAC and QPSS/QPAC is 10dB smaller than P1dBin(Input Refered 1dB Gain Compression Point) as Class-A amplifer. You had better set level of moderate signal in QPSS smaller than P1dBin(Input Refered 1dB Gain Compression Point) as Class-A amplifer especially for Shooting-Newton QPSS. See threads after following. http://www.designers-guide.org/Forum/YaBB.pl?num=1262828862/18#18 |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 22nd, 2010, 4:35am Its a single ended design with input matching,stability , harmonic tank and output matching network. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 22nd, 2010, 4:39am purplewolf wrote on Jun 22nd, 2010, 4:35am:
Use the followings. Don't use HB-SS or PSS/PAC. (1) Two-tones HB based on one fundamental frequency in Agilent ADS (2) Two-tones CR(=HB) based on one fundamental frequency in Agilent GoldenGate (3) Two-tones HB-PSS in Cadence Spectre (4) Two-tones HB based on two fundamental frequencies in Agilent ADS (5) Two-tones CR(=HB) based on two fundamental frequencies in Agilent GoldenGate (6) Two-tones HB-QPSS in Cadence Spectre |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 22nd, 2010, 4:52am A Parallel RC network in Series with the gate to ensure stability . The input matching is done after stability network. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 22nd, 2010, 4:54am purplewolf wrote on Jun 22nd, 2010, 4:52am:
See the followings. http://www.designers-guide.org/Forum/YaBB.pl?num=1218635777/5#5 http://www.designers-guide.org/Forum/YaBB.pl?num=1272344339/3#3 purplewolf wrote on Jun 22nd, 2010, 3:40am:
When I have spare time, I will check P1dBin and IIP3 for Class-B amplifier using Agilent ADSsim although I also have Cadence Spectre. See Class-B Power Amplifier in the following. http://edocs.soco.agilent.com/display/ads2009/About+Amplifier+DesignGuide Class B > Spectrum, Gain, TOI and 5thOI Points, and PAE vs. Power ; "HB2TonePAE_Pswp_ClassB.dds" |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 22nd, 2010, 5:10am but what does stability network has to do with IIP3 and OIP3?? the amplifier is already stable |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 22nd, 2010, 5:10am yes i get the same result for all three analysis... |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 22nd, 2010, 5:14am purplewolf wrote on Jun 22nd, 2010, 5:10am:
purplewolf wrote on Jun 22nd, 2010, 5:10am:
I will check P1dBin and IIP3 for Class-B amplifier using Golden Standard RF Circuit Simulator Agilent ADSsim. If you show me netlist of your Class-B amplifier, I can resimulate it using various simulators. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 22nd, 2010, 6:12am i have generated the netlist but which file you would be needing to simulate it...and where to find the netlist file? |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 22nd, 2010, 7:10am here the netlist file... change extension to .scs |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 22nd, 2010, 11:01am here are the files. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 22nd, 2010, 11:03am thats the other |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 22nd, 2010, 2:50pm this is a device in umc 90nm... i think its parameters dont appear in netlist.. how to get it?? |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by RFICDUDE on Jun 22nd, 2010, 4:03pm Dude, you can't share proprietary foundry models and/or parameters. Unless you have legal permission from the foundry to do so (usually requires a three way nondisclosure agreement). Sometimes the EDA company has existing agreements with foundries, so in these cases you can share netlists with someone from the EDA company and they can simulate your netlist because they have or can obtain the foundry models. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 23rd, 2010, 12:07am yeah.... i cant share.. pancho_hideboo can you do a favor(when u have really free time and relaxed :)) ,,, could u check iip3 oip3 in cadence for device biased in class B and tell me how u make the class B obey the text book equations of oip3= iip3+gain , iip3 = 9.6 + p1db as derived in razavi ..whether these equations are valid for class B since its output current is half sinusoid.... I am really stuck :( |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by RFICDUDE on Jun 23rd, 2010, 3:17am 1. A class B or even class AB amplifier may not follow the classic relationships between OIP3 and P1dB! Why? The power series expansion analysis that leads to the classic relationships between different order distortion components is usually performed on, what is assumed to be, a class A circuit. In a class A circuit, the nonlinear response of the circuit is not dependent on the input signal (it is only dependent on the nonlinear device and operating point). For class B and deep AB circuits the quiescent current in the transistor(s) is dependent on the signal levels applied to the circuit, so effectively the power series coefficients may be changing as a function of the signal drive level. When this happens the assumption that the amplifier nonlinearity is characterized by single values for intermodulation intercept points is no longer true (i.e. OIP3 is not constant for all signal levels below compression). So, for a true class B amplifier the OIP3 at small signal may be horribly smaller than you expect from a class A amplifier where OIP3 is constant. So what do you do? For a nonlinear power amplifier design you care about meeting a OIP3 or equivalently a IM3 or ACPR number at some specific average output power level (usually the highest required average power). So you could focus on meeting a IM3 number at that power level, but you want to be sure to still sweep two-tone input power to make sure you are not in a cancellation null where the IM3 is good and may become slightly worse as the the input power is reduced before declining again. 2. Simulation I don't trust simulating linearity of class B designs with simulation techniques that assume moderate or weak nonlinearity (QPSS and PAC). I would first use two-tone transient, PSS or even harmonic balance (PSS HB) to understand what is going on large signal in the circuit then (once I trust the simulation is yielding the expected results) I can try the other analysis techniques and compare results before trusting the fast analysis techniques. Again, for large signal operation (within 5-10dB of P1dB) be sure to sweep the two-tone power and look at the behavior of IM3. I hope this helps a little. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 23rd, 2010, 4:15am First of all, you have to understand difference between one large signal drive and two large signal drive correctly. True P1dBin is defined for one large signal drive. So P1dBin defined under two large signal drive has to be corrected. True P1dBin will be 3~6dB larger than P1dBin defined under two large signal drive. I usually use following relation. P1dBin_One_Input=P1dBin_Two_Inputs+4.5dB Some people set "Pin_dBm-3dB" for each tone's power in two large signal drive. This is appropriate if you evaluate correct P1dBin from two large signal drive. But this is never appropraite if you evaluate IM3 or IP3. In evaluation of IM3 or IP3, you have to set "Pin_dBm" not "Pin_dBm-3dB". For example, starter of the following thread are misunderstanding. http://www.designers-guide.org/Forum/YaBB.pl?num=1262828862/26#26 The followings are summary of my simulation results of Class-B Amplifier. (1) One Large Tone HB Analysis P1dBin=24dBm This P1dBin is true value. If I roughly estimate P1dBin as Class-A operation from P1dB as Class-B Operation, it will be P1dBin=24-6=18dBm. (2) Two Large Tone HB Analysis P1dBin=19dBm IIP3in=28.275dBm Here this P1dBin is defined under two large signal drive, so this is not correct value. So we have to correct this P1dBin value. In this case, P1dBin_One_Input=P1dBin_Two_Inputs+4.5=19+4.5=23.5dBm. This corrected value is well matched to result of (1). (3) One Large Tone + One Small Signal HB Analysis P1dBin=24dBm IIP3=27.114dBm The followings are conclusion for analysis of nonlinear amplifier such as Class-B and Class-C Amplifiers. (1) IP3 can be defined for only linear system essentially. You have to use IM3[dBc] for characterization for nonlinear amplifier such as Class-B and Class-C Amplifiers. (2) IM3 output is not subjected to gradient of 3dB/dB line except for some region of input power level. (3) IM3 characteristics of nonlinear amplifier such as Class-B and Class-C Amplifiers is affected by not only AM/AM but also AM/PM characteristics. On the other hand, P1dBin is pure AM/AM characteristics. Well-known relation of "IIP3=P1dBin+9.6dB" is derived under only AM/AM characteristics. (4) Null of IM3 is true phenomena which is also observed in actual measurement. This extremely small IM3 is a result of exquisite balance of AM/AM and AM/PM characteristics. (5) You can not apply slave Small Signal Analysis subjected to master Large signal Analysis such as HBSS, PSS/PAC, QPSS/QPAC for nonlinear amplifier such as Class-B and Class-C Amplifiers. Especially you must not apply them for evaluation of IM3. Again see http://www.designers-guide.org/Forum/YaBB.pl?num=1277203226/3#3 (6) If you use estimated P1dBin as Class-A operation and IIP3 where IM3 is relative subjected to gradient of 3dB/dB line, IIP3=P1dBin+9.6dB can be satisfied. In this case, P1dBin=18dBm and IIP3=28.275dBm. P1dBin+9.6dB=27.6dBm is close to IIP3=28.275dBm. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 23rd, 2010, 2:53pm many thanks pancho_hideboo & RFICDUDE...let me absorb ur deep insight views......... :P |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 28th, 2010, 7:32am If I replace true FET with behavioral model FET of Class-B operation like following, Idrain=a1*Vgs+a3*Vgs3 for Vgs>=0.0 Idrain=0.0 for Vgs<0.0 IM3 of HB2 and HB1SS are coincident and are subjected to 3dB/dB line completely regardless of half sinusoid output current. This model is : - No frequency characteristics - Simple AM/AM characteristics having only a1 and a3. - No AM/PM characteristcics Well-known relation of "IIP3=P1dBin+9.6dB" is derived under this condition. http://edocs.soco.agilent.com/display/ads2009/Amplifier2+%28RF+System+Amplifier%29 IM3 characteristics of nonlinear amplifier such as Class-B and Class-C Amplifiers is affected by not only AM/AM characteristics due to a1 and a3 but also AM/PM characteristics and AM/AM characteristics due to a2, a4, a5, a6, a7,.....etc. Here "ai" is coefficient of order "i" in input/output relation. The following is not appropriate. pancho_hideboo wrote on Jun 23rd, 2010, 4:15am:
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 28th, 2010, 3:38pm Am i right in making this claim "that IIP3 and OIP3 should never be considered/trusted for class B and C amplifiers and only IM3 should be considered." |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by RFICDUDE on Jun 28th, 2010, 5:08pm Ah ha, it seems a little "EDA tool play" is instructive sometimes if, of course, one knows what one is doing! ;) |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 29th, 2010, 2:57am Show me your plot results of Pfund_dBm and Pim3_dBm v.s Pin_dBm. Are they subjected to 1dB/dB and 3dB/dB lines respectively ? purplewolf wrote on Jun 28th, 2010, 3:38pm:
Sometimes IP3 is not used even for Class-A Power Amplifier. RFICDUDE wrote on Jun 28th, 2010, 5:08pm:
"EDA Tool Play" is no more than "Tool Play" and never can exceed actual measurements. pancho_hideboo wrote on Jun 28th, 2010, 7:32am:
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 29th, 2010, 4:36am For my case ,in Spectre, if the amplifier is biased in class A and Class AB mode the classical relationship 1)OIP3 = IIP3+Gain 2)IIP3=P1db+9.6 are fully obeyed . I used a)Two Tone PSS b)Two Tone QPSS c)PAC+PSS Sweep and all of them give same results. Another strange thing is I am getting is the same values of OIP3 and IIP3 for class A and class AB . For Class A,VGS=1.2V ( 1 ,2 Obeyed) P1dB(IN) = 18.6dBm, P1dB(OUT)=26.9dBm,Gain = 8.65 IIP3 =24.18dBm,OIP3=33dBm For Class AB,VGS= 0.8V ( 1 ,2 Obeyed) P1dB(IN) = 15.4dBm, P1dB(OUT)=23dBm,Gain = 7.5 IIP3 =24dBm,OIP3=33dBm For Class B ,VGS=0.55V( 2 Not Obeyed, ??1 obeyed ??) P1dB (IN) = 23dBm , P1dB(OUT)=27.65dBm,Gain = 6.6 dB IIP3 =12.2dBm,OIP3=17.98dBm Long story short: The Spectre includes the IM null while extrapolating the Intercept lines . Since the BIG NULL in Class B makes the amplifier not obey the classical equations..Whereas for Class A , Class AB PA's ,LNA etc IM null is in-significant or near to the amplifier saturation and so the 3db slope is not effected and the classical equations obeyed. I am attaching pics for Class A and Class B ..The IIP3 , OIP3 are independent of Input Power Level Sweep. . |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 29th, 2010, 4:47am Your input power level is too small for evaluation of Class-B Amplifier. I can't judge whether your simulation results are reasonable or not. But I can say your simulation setup for QPSS is not appropriate. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 29th, 2010, 4:53am I have used higher input power levels also..you can see in Class A(Plot 2) and Class B (Plot 2) |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 29th, 2010, 5:01am i used the same setup for Class A and Class AB and the results are ok as indicated above. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 29th, 2010, 5:07am Also the results are same for PAC & PSS ,Two tone PSS as well.. Only the non-linearity of Class B makes the difference |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 29th, 2010, 5:17am purplewolf wrote on Jun 29th, 2010, 4:53am:
Your extrapolation point is too small. If you use such small input power, power conversion efficiency of Class-B or Class-C amplifier is very small. Consider how output level of -200dBm is too small. Do you have an experience of actual measurement ? Do you think it is possible to measure -200dBm. And I can say your QPSS setup is not appropriate. Quote:
Set maxharms=[9 9] or maxharms=[15 15] I set maxharms=[15 15] in HB2 analysis of Agilent ADSsim. Can you plot results of 2tone-HB-QPSS as same style as mine ? Don't use Direct Plot Form. If I have device model of your MOSFET, I can resimulate and confirm your circuit by using more reliable simulator. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 29th, 2010, 6:40am What extrapolation point should be used in Spectre then?? EP should be low so as to have 3 db slope at low power levels. I dont have any experience in measurement . The FET I am using is BPW_N_25_RF from UMC 90nm. here'my qpss setup in pics.. what to use in place of Direct Form?? |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 29th, 2010, 6:51am You set f1=2490MHz as small signal in PAC analysis. Show me followings. (1) Over Plot Results of fundamental output(f1=2490MHz, f2=2495MHz) for QPSS and PSS/PAC. (2) Over Plot Results of IM3 output for QPSS(2485MHz and 2500MHz) and PSS/PAC(2500MHz). If you can not do them, upload "simulation/"test_bench_name"/spectre/schematic" for QPSS and PSS/PAC. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 29th, 2010, 7:21am theres a slight difference in the third order , the fundamental are the same |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 29th, 2010, 7:37am Show me version of Cadence Spectre you use. Also show me time waveform for Idrain, Vdrain, Iload and Vload. These can be available in PSS results for PSS/PAC. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 29th, 2010, 10:10am Here are the waveforms for drain current ,drian voltage, output current and output voltage |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 29th, 2010, 10:10am . |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 29th, 2010, 10:12am The version is 7.0.1.273 |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 29th, 2010, 10:34am purplewolf wrote on Jun 29th, 2010, 10:10am:
My request is time waveform with Pin_dBm as parameters. See my simulation results surely. I don't think your amplifier is Class-B operation, although I don't know what Pin_dBm value is used for time waveform you showed. purplewolf wrote on Jun 29th, 2010, 10:12am:
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 30th, 2010, 3:02am here are the Pin_dbm sweep results from -30 to 30.. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by RFICDUDE on Jun 30th, 2010, 3:18am When I look at your earlier two-tone sweep data, it looks like there is 1. a little bit of gain expansion before compression (although it is difficult to tell from just looking at the plot) 2. the IM3 has definite dips (nulls if you like) near where the gain expansion is occurring IF you do have some gain expansion before compression then this will definite violate the condition necessary for 9.6 dB P1dB to OIP3 relationship. The gain expansion can make P1dB happen at an input power level that is higher than that of a classic class A amplifier. I will look at the latest plots later, but it seems your circuit is operating class AB. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 30th, 2010, 3:47am yes exactly..the nulls make my class B violate the expressions.. well , its almost class B. :) |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 30th, 2010, 4:28am purplewolf wrote on Jun 30th, 2010, 3:47am:
http://www.designers-guide.org/Forum/Attachments/IVD.png This drain current is not for Class-B operation completely. On the other hand, drain currents in your Transient Analysis are for Class-B operation. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 30th, 2010, 5:05am i get this problem of ''....not a kept output'' when plotting current through pss....so , i prefer transient in plotting currents because i am unable to fix that problem with pss other than using some 'tricks'. the transient current waveform is accurate... you can ignore IVD.png or help me figure out this problem with pss?? |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 30th, 2010, 5:10am purplewolf wrote on Jun 30th, 2010, 5:05am:
purplewolf wrote on Jun 30th, 2010, 5:05am:
Try to use Shooting-Newton-PSS not HB-PSS. Do you have other vendor's simulator such as Agilent RFDE(ADSsim), Agilent GoldenGate, Synopsys HSPICE-RF, Mentor eldoRF ? |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 30th, 2010, 6:03am yes , my qpss,pss-pac simulation are correct.. i am trying to figure out how to deal with t '...not a kept output ' problem i get in current......tahts why for the IV waveforms i use transient rather than pss.. yes , i only have golden gate but i havent used it once...im only relying on spectre. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 30th, 2010, 6:10am purplewolf wrote on Jun 30th, 2010, 6:03am:
purplewolf wrote on Jun 30th, 2010, 6:03am:
See http://www.designers-guide.org/Forum/YaBB.pl?num=1268404959/7#7 purplewolf wrote on Jun 30th, 2010, 6:03am:
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jun 30th, 2010, 6:18am thats the problem i cant get around with.. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jun 30th, 2010, 6:22am purplewolf wrote on Jun 30th, 2010, 6:18am:
(1) Use "analogLib/iprobe" instead of saving pin current of drain of M1. As far as my memory is correct, saving pin currrent can't work in HB analysis of Cadence Spectre. So try to use Shooting-Newton-PSS not HB-PSS. If you use Shooting-Newton-PSS, you can save pin current. (2) Don't use Direct Plot. Use Result Browser. The followings are general notes for you. - Always describe correct tool's name and vendor's name which you use as tool or simulator. - Don't do multiple posts which are same content. - Don't request source code or behavioral model without any efforts. - There are many simulators which have analyses called as PSS, PAC and Pnoise. - Describe in detail with using correct terminologies. - Warnigns are different from Errors. - ADS is not name of simulator. - There is no tool which name is Cadence. - Don't use Direct Plot of Cadence ADE blindly without knowing definition. - All gains in Direct Plot of Cadence ADE are "right", "true" and "practical" voltage gain. - Don't mix up Simulation with Post Processing. They are completely different phase. - MATLAB are different from Simulink. - Learn measurements using actual instruments. Not "EDA Tool Play |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jul 1st, 2010, 3:11am - Don't use Direct Plot of Cadence ADE blindly without knowing definition. - All gains in Direct Plot of Cadence ADE are "right", "true" and "practical" voltage gain. I dont get these points exactly.. I have managed to get current waveform through that is like my transient waveform by putting current probe but its flipped...you can have a look..my transient and pss are same. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jul 1st, 2010, 4:35am purplewolf wrote on Jul 1st, 2010, 3:11am:
purplewolf wrote on Jul 1st, 2010, 3:11am:
Is your plot result Shooting-Newton-PSS ? purplewolf wrote on Jul 1st, 2010, 3:11am:
http://www.designers-guide.org/Forum/YaBB.pl?num=1237656418 http://www.designers-guide.org/Forum/YaBB.pl?num=1236837379/4#4 http://www.designers-guide.org/Forum/YaBB.pl?num=1272508752/1#1 |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jul 1st, 2010, 6:01am i mean that the plots via transient and HB-PSS,SN-PSS are the same... |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jul 1st, 2010, 6:07am purplewolf wrote on Jul 1st, 2010, 6:01am:
purplewolf wrote on Jul 1st, 2010, 3:11am:
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jul 1st, 2010, 6:24am flipped... current wave shape is exactly the same as in transient except its rotated about axis or multiplied by -1. |
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by pancho_hideboo on Jul 1st, 2010, 6:39am purplewolf wrote on Jul 1st, 2010, 6:24am:
It is very difficult to compare time waveforms between PSS and Transient analyses since its initial phases are different between them. If you compare them with completely same initial phases, you can observe clear difference between them. But from practical point of view, you can ignore such small difference. purplewolf wrote on Jul 1st, 2010, 6:24am:
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Title: Re: Class B RF Power Amplifier ,IIP3/OIP3 Spectre Post by purplewolf on Jul 6th, 2010, 4:13am million thanks for your help! :) |
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