I have posted a custom symbols guide in the Files. It is in the 'Tut' folder. Thanks to Mike Englehardt for his comments.

I used a B source to make an inverter gate. sim .subckt inv 1 2 b1 3 0 v=!(v(1)) r1 3 2 100 c1 2 0 10P .ends inv vin 10 0 pulse 0 10 1m 1n 1n 2m 4m x1 10 20 inv ic=0 r1 20 0 1meg .tran 100u 10m 0m 100u .end The behavior of the circuit seems to be ok but I got in the "spice error log" the following message: Circuit: sim Error: unknown token in: "[!](v(1))"Date: Sun Oct 13 22:16:06 2002 Total elapsed time: 0.050 seconds. tnom = 27 temp = 27 method = modified trap totiter = 792 traniter = 789 equations = 6 tranpoints = 383 accept = 357 rejected = 26 trancuriters = 0 I have no idea about this error, someone can give me an help? Stefano

The potentiometer model in the file area is missing the subcircuit. Only the .asy fil is there - in both directories Larry

Hello, I'm experimenting with adding a custom model to use in SwitcherCADiii (I'm adding a Max931, but with a 'DIP8' symbol and using the Spice model from Maxim -- almost the same as an LTC1540). I have the symbol part working (Ralph's guide was very useful, I have some experiences to add about the semantics of PINs and their ordering if anyone interesting). I'm now as far as having the model start to run, but just get a message box: Spice error Error: Unknown device type in: xu1 n003 n002 n001 0 n002 n002 out 0 max931.fam max931 (which just looks like the call to the subcircuit with the filename and Value added). There's no additional information in the .log file. Anyone know how I can get more detailed information on the unknown device type, or do I just have to plough through the model 'by eye'? -- Mike Cowlishaw Coventry, UK

PS: It's rumored that most of what the subcircuit models attempt to do can be done by specifying parameters in the higher-level MOS models (the "LEVEL=__" parameter) but I haven't found any documentation or explanation of how to do it. Dale

Hi, Pardon my ignorance as I am a Ham running small spice circuits, but I cant find any documentation on what the dot command, .backanno, means. I would appreciate a pointer to the documentation for this command. Ralph KB9KKR

I've only been using LTSpice for a couple of weeks and have finally gotten stuck. I'm trying to import some additional MOSFET models (for example, http://www.onsemi.com/pub/Collateral/NTMD6P02R2.LIB ) and am at a loss on how to do it. I've waded through the online manuals and googled forever. I tried just copying values from the PSpice model into the standard.mos file but it's not clear what to copy. For example, in standard.mos the first parameter is "Rg". The manual states that "Rg" is "Gate ohmic resistance". But in the PSpice model the only line with Rg is "RG 2 7 10.013". Now since every other line in the standard.mos file has Rg=3 I'm totally confused on how to proceed. Can anyone provide any hints of guidance on how to import these? Thanks!

Version 2.00 of LTspice/SwitcherCAD III is now available. From Version 1.16s, this version introduces 1. a graphical symbol editor 2. hierarchical schematics 3. improved help documentation. The schematic file format changed a little, but 2.00 should be able to read the old schematics and symbols. I'm particularly interested in feedback relating to (i) things that are now broken and ii) sections of the help that don't tell you how to do something. Best Regards, Mike Engelhardt __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com

I experienced the following problem using a lossy transmission line. Even though the simulation (.op) can proceed, a non fatal error is occuring all the time: Unknown parameter "td". As I read in the online help Td is not a parameter of a lossy transmission line. So I wonder wy this problem is occuring. Also, I haven't f find in the help a clear procedure explaining where to insert the value of the parameters of a complex model like a transmission line. After a few try, I have created a spice directive like the folowing : " model neg_terre_1 LTRA(R=9.6µ G=122µ L=0 C=0 len=10000) " and it worked. Finnally, I want to extract the numbers appearing at the end of the .raw file. Can you tell me the format of this string? Thanking you in advance for your reply Michel Allaire ing. SSTM Société de Transport de Montréal Soutien opérationnel Courriel : michel.allaire@... Téléphone : (514) 280-6335 Télécopie : (514) 280-5677 Tél. privé : 6301

Hello, After a re-install of my system, I downloaded the newest edition of LTSpice. Now I tried out to simulate a simple circuit, and I discovered that whatever it is, my circuit works well, but with the STEP command I get the error : Multiple instances of "Cjo=1.0760e-12". What could this possibly be? What could I do to solve the problem? Here my short circuit: Kondensatormeßbruecke *Widerstände R1 2 0 1K R2 3 0 {var} *Kondensatoren C1 1 2 1u Cubk 1 3 2u *Strom- und Spannungsquellen Vsin 1 0 SIN(0 5 200) .PARAM var=1K ** Analysis setup ** .OP .STEP LIN PARAM var 1 10K 1K <<<< This Line gives the error! .tran 50us 50m .END Greetings, Bernhard Krämer ______________________________________________________________________________ Werden Sie kreativ! Jetzt HTML-Mails nicht nur schreiben - nein - GESTALTEN, bei WEB.DE FreeMail! http://freemail.web.de/features/?mc=021141

Dear Mr. Sennewald, Thank you very much! You gave the final hint to solve the problem! And I already believed in a bug... As you said, there is no semiconductor device in my circuit. In fact, what you had was the whole circuit... only one line was missing: the line which indicates what library I use. After deleting it, my circuit worked! I guess, my capacity Cubk (which should mean "C unbekannt" (= "C unknown") ) had the same name as any of my models in a library. I will look for it. Thank you very much for your help! Truly Yours Bernhard ______________________________________________________________________________ ASCII-Bilder und SMS-Sprueche bei WEB.DE FreeMail - auswaehlen, einfuegen und versenden! http://freemail.web.de/features/?mc=021168

Is there a simple way to convert TI models to run in LTSpice?

Hi everybody, I am a new user of LTSpice. Looking into the model list I am not able to find the models for a semiconducor (diffused) resistors and capacitors. They are not very important but some netlists are using them. Are these models available in LTSpice? They are standard models in Berkeley Spice3, may be useful to add them for compatibility. Is there an upper limit for the numeber of components in the standard.* libraries (diode,resistor,capacitor...)? Using the .STEP statement it seems difficult to analyze the different waveforms because it is not possible (is it right?) to understand which value of the parameter is related with a particular waveform. Is there a way to show which value is used with any waveforms? Regards Massimo -- ''~`` ( o o ) +------------------.oooO--(_)--Oooo.------------------+ | | | e-mail: gaspari@... | | | | ICQ # = 166939207 | | | | PGP fingerprint16: | | 76 80 F2 F9 8D 70 F3 D1 42 2B CD 80 29 49 CB 25 | | | | .oooO | | ( ) Oooo. | +---------------------&#92; (----( )--------------------+ &#92;_) ) / (_/

Hello Group, I discovered LTSpice a few days ago and I find it very usefull, fun and easy-to-use :-) I am now trying to use mixed-mode simulation, and I cannot edit nor see the models of simple parts like DFLOP (I just want to modify Hold Time, Threshold, etc.). I did it easily for simple analog parts (like nmos,pmos), but no way to find a file (even after a search in the help files and FAQ) for digital parts...maybe I should buy new glasses. A Hint? Thank you in advance for your help Christian Néel

Hi Neil /New user: how to edit digital models? ----------------------------------------------- Try these: CD4093.asc ------------------------------------------------ Version 4 SHEET 1 892 692 WIRE 288 304 304 304 WIRE 160 320 112 320 WIRE 160 256 112 256 WIRE 160 272 128 272 WIRE 128 272 128 352 WIRE 128 352 160 352 WIRE 160 352 160 336 WIRE 160 352 240 352 WIRE 240 352 240 320 WIRE 160 352 160 368 FLAG 112 256 a IOPIN 112 256 In FLAG 112 320 b IOPIN 112 320 In FLAG 304 304 c IOPIN 304 304 Out FLAG 160 368 gnd IOPIN 160 368 BiDir SYMBOL C:&#92;Program&#92; Files&#92;LTC&#92;SwCADIII&#92;Digital&#92;and 256 224 R0 WINDOW 3 0 0 Invisible 0 SYMATTR Value Vlow=.1 Vhigh={VDD} SYMATTR InstName A1 SYMATTR Value2 Trise=2n Tfall=2n SYMBOL C:&#92;Program&#92; Files&#92;LTC&#92;SwCADIII&#92;Digital&#92;schmtbuf 160 192 R0 WINDOW 3 8 60 Invisible 0 SYMATTR Value Vt={Vtt} Vh={Vhh} Trise=10n Tfall=10n SYMATTR InstName A2 SYMATTR Value2 Vlow=.1 Vhigh={VDD} Td=193n SYMBOL C:&#92;Program&#92; Files&#92;LTC&#92;SwCADIII&#92;Digital&#92;schmtbuf 160 256 R0 WINDOW 3 17 89 Invisible 0 SYMATTR Value Vt={Vtt} Vh={Vhh} Trise=10n Tfall=10n SYMATTR InstName A3 SYMATTR Value2 Vlow=.1 Vhigh={VDD} Td=193n ------------------------------------------------ CD4093.asy ------------------------------------------------ Version 4 SymbolType BLOCK LINE Normal 16 -32 -32 -32 LINE Normal 17 32 -32 32 LINE Normal -32 32 -32 -32 LINE Normal 0 -16 16 -16 LINE Normal -8 16 0 -16 LINE Normal -16 16 -8 16 LINE Normal 0 16 -8 16 LINE Normal 8 -16 0 16 CIRCLE Normal 64 8 48 -8 ARC Normal -15 -32 48 32 17 32 16 -32 WINDOW 0 49 -42 Left 0 WINDOW 1 66 28 Left 0 PIN -32 -16 NONE 8 PINATTR PinName a PINATTR SpiceOrder 1 PIN -32 16 NONE 8 PINATTR PinName b PINATTR SpiceOrder 2 PIN 64 0 NONE 8 PINATTR PinName c PINATTR SpiceOrder 3 PIN 0 32 NONE 8 PINATTR PinName gnd PINATTR SpiceOrder 4 ------------------------------------------- and finally an example: Relax.asc ------------------------------------------- Version 4 SHEET 1 900 700 WIRE 80 -80 160 -80 WIRE 160 -80 160 48 WIRE 160 48 112 48 WIRE 16 32 -16 32 WIRE -80 32 -80 96 WIRE 16 64 -16 64 WIRE -16 64 -16 32 WIRE -16 32 -80 32 WIRE -16 32 -16 -80 WIRE -16 -80 0 -80 WIRE -80 192 -80 176 WIRE -80 176 48 176 WIRE -80 176 -80 160 WIRE 48 176 48 80 FLAG -80 192 0 SYMBOL C:&#92;Program&#92; Files&#92;LTC&#92;SwCADIII&#92;DC4093 48 48 R0 SYMATTR InstName U1 SYMATTR SpiceLine k=3 VDD=5*k Vtt=2.4*k Vhh=.532*k SYMBOL cap -96 96 R0 SYMATTR InstName C1 SYMATTR Value 1n SYMBOL res 96 -96 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R1 SYMATTR Value 20k TEXT -100 216 Left 0 !.tran 1000u -------------------------------------------

Please, change in the schematic CD4093.asc and symbol CD4093.asy node name gnd to G. It is universal, you can shift the level of the "GND" node. Peter

I created a symbol to represent a schematic (symbol saved as "block" (.asy)). When I placed it in a higher level schematic and tried to run a sim, I got an error message telling me that subcircuits cannot be nested. The lower level schematic does have a subcircuit in it, and a .lib directive to call that subcircuit, but this must not be a limitation of heirarchical schematics, as it would severely limit its usefulness. I'm certain I'm doing something wrong. Anyone know what that might be? Ron Harrison

Thanks again to Helmut and Peter. My digital design works now very well, with "real world" parameters. Christian

I have no experience with Spice and what I know comes from the help file and the previous posts. I guess we all have to start somewhere. What I wanted to do was call up a model from a sidac library downloaded from Intusoft. With no better ideas on how to go about this I used the DIAC symbol from the LT library, renamed it and saved it to the symbol folder. I dropped it on my schematic and opened up the Component Attribute Editor. In the value field I typed K1100E70 (K1100E70 is the model in the library). On the schematic I dropped a Spice directive .inc demsidac.lib. When I run the circuit I get an error message `Multiple instances of "any". So is there `any' hope for me? Version 4 SHEET 1 892 692 WIRE -64 272 64 272 WIRE -96 272 -64 272 WIRE -64 336 -64 352 WIRE -64 352 64 352 WIRE -720 352 -720 368 WIRE -64 352 -304 352 WIRE -720 272 -304 272 WIRE -304 272 -176 272 WIRE -304 336 -304 352 WIRE -304 352 -720 352 FLAG -720 368 0 SYMBOL C:&#92;Program&#92; Files&#92;LTC&#92;SwCADIII&#92;lib&#92;sym&#92;voltage -720 256 R0 WINDOW 3 24 104 Invisible 0 WINDOW 123 0 0 Left 0 WINDOW 39 24 132 Left 0 SYMATTR Value EXP(0 1000 0 1.2us 10us 50us) SYMATTR SpiceLine Rser=.1 Cpar=.01uf SYMATTR InstName V1 SYMBOL C:&#92;Program&#92; Files&#92;LTC&#92;SwCADIII&#92;lib&#92;sym&#92;ind -192 288 R270 WINDOW 0 32 56 VTop 0 WINDOW 3 5 56 VBottom 0 SYMATTR InstName L3 SYMATTR Value 10µ SYMATTR SpiceLine Ipk=3.9 Rser=0.038 Rpar=94000 Cpar=2.8p mfg="Coilcraft" pn="DO3316P-103" SYMBOL C:&#92;Program&#92; Files&#92;LTC&#92;SwCADIII&#92;lib&#92;sym&#92;res 48 256 R0 SYMATTR InstName R1 SYMATTR Value 1 SYMBOL C:&#92;Program&#92; Files&#92;LTC&#92;SwCADIII&#92;lib&#92;sym&#92;polcap -80 272 R0 WINDOW 3 24 64 Left 0 SYMATTR Value 1.4µ SYMATTR InstName C2 SYMATTR Description Capacitor SYMATTR Type cap SYMATTR SpiceLine V=50 Irms=2 Rser=.007 MTBF=0 Lser=0 ppPkg=0 SYMBOL C:&#92;Program&#92; Files&#92;LTC&#92;SwCADIII&#92;lib&#92;sym&#92;Misc&#92;DIAC1 -336 272 R0 SYMATTR InstName U1 TEXT -754 408 Left 0 !.tran 0 .001s 1us 1us TEXT -480 464 Left 0 !.include demsidac.lib * C:&#92;Program Files&#92;LTC&#92;SwCADIII&#92;My circuits&#92;filter.asc V1 N002 0 EXP(0 1000 0 1.2us 10us 50us) Rser=.1 Cpar=.01uf L3 N002 N001 10µ Ipk=3.9 Rser=0.038 Rpar=94000 Cpar=2.8p mfg="Coilcraft" pn="DO3316P-103" R1 N001 0 1 C2 N001 0 1.4µ V=50 Irms=2 Rser=.007 MTBF=0 Lser=0 ppPkg=0 XU1 N002 0 K1100E70 .tran 0 .001s 1us 1us .include demsidac.lib .backanno .end

Reiner, I got the same or similar error message, when I tried to simulate a square-root circuit model. Of course, it is a big different between applications, but maybe good to know, why happened it. The reason was the negative value "under" sqrt, what is imaginary number. :) . Peter