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Re: LT1171 model: syncronization not working
¿ªÔÆÌåÓýOn many of the LT switch mode controllers, the sync function is not implemented in the spice model. Don¡¯t know about that specific one.Jim ' James Wagner Oregon Research Electronics
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"4 GROUP.zip" upload
Jeff (kinarfi) uploaded a file "4 GROUP.zip" to the group's Temp
folder, but there is no message yet to the group about it. I don't know if you forgot to send one, or if it is just held up by today's unreasonably slow Yahoo computers. Your upload says "WHAT AM I DOING WRONG WITH MY BS250P BS170". I think your keyboard's Caps-lock key is stuck. Either that, or you are shouting. Here is what's wrong. Problem 1: When you created your custom NMOS and PMOS symbols, you put the transistor name in too many places. In the Attributes, you have SpiceModel = BS250P Value = BS250P Doing that, causes the transistor to go into the SPICE Netlist like this: U1 OUT-1 N002 N001 BS250P BS250P Note that BS250P appears twice. It must be only once. Remedy: Edit the two symbols. Remove the SpiceModel attribute (leave it blank). Problem 2: You set the Prefix to "U". The U prefix is for lossy RC transmission lines, but your models are subcircuits. Remedy: Edit the two symbols. Change Prefix from U to X. After saving both symbols, close and re-open the schematics. Problem 3: Draft2.asc doesn't work because LTspice doesn't have a 2N7000 model in its library. But it has the 2N7002, which is similar. Regards, Andy |
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Re: Thyristor library
(Another reply that vanished into the Internet):
Hassan wrote: "I have found either the .lib file or the symbol !!! " That is good. The first thing to understand is that they are almost completely independent of one another. A symbol is just an icon, nothing more. LTspice has some of the symbols already. In the Select Component (F2) menu, choose the [Misc] area, then you can find DIAC, SCR, and TRIAC symbols. If you found .lib files, then you found their SPICE models. Now all you need to do is: (A) include the .lib file in your simulation, and (B) associate the symbol with the model inside the library file. To include the .lib file, first put the .lib file in the same folder with your schematic that uses it. Then add this as a SPICE Directive on your schematic: .lib filename.lib To associate the symbol with the model: Right-click on the symbol body and make sure Prefix is set to X. Open the .lib file in a text editor (such as Wordpad) to see what's inside it. There should be a subcircuit definition for the part you want to use. Scroll down until you find it. It might look something like this: .SUBCKT 2N6071B MT2 G MT1 Now you know the actual name of the model: 2N6071B. And you know the order of the pins: MT2, G, MT1. There could be several .SUBCKTs in the same file, each for a different part. Find the one you want. Go back to your schematic. Edit the name next to the symbol, and change it from "TRIAC" (or "SCR" or "DIAC"), to the name of the subcircuit you want to use ("2N6071B" in this case). The tricky part is to make sure the order of pins is correct. For a Triac, LTspice assumes the order of pins is MT2, G, MT1. If the order differs from that, then you should edit the .lib file and change the pins in the above .SUBCKT line to make them in that order. This may take a little effort to understand what the pins are, when they don't have those specific names. Regards, Andy |
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Re: Current Dependent Voltage Source
Wow, emails to [LTspice] are not making it again!
Here is a message I sent several hours ago that hasn't shown up yet: --- "rmoreno.phone" asked how to enter a table of measured values for her/his CCVS. Vlad might have had the table descriptions a little bit confused with respect to your question, because I think the data you have is voltage/current values, not voltage/time values. You wanted a controlled or dependent source, not an independent source. Using SPICE's built-in H element (current controlled voltage source or CCVS), LTspice *MIGHT* have the ability to accept a table of current/voltage values. See the Help pages for E (VCVS) and G (VCCS) elements. A table is listed as an option. "A look-up table is used to specify the transfer function." The same 'table' description is not listed for the F (CCCS) and H (CCVS) elements. I am not sure if that was an omission on those Help pages, or if that option really doesn't exist for those two controlled sources. The "LTwiki" (www.ltwiki.org) is where I usually go when I have questions about the Help pages. Unfortunately, the LTwiki also doesn't show a table option for the CCVS. That leads me to believe that you can't use a table with the standard CCVS element. But LTspice's B-elements can do that and much more. Here is from the Help page for B-elements: table(x,a,b,c,d,...) Interpolate a value for x based on a look up table given as a set of pairs of points. Start with a Bv symbol, then right-click on "V=F(...)" and edit it. I think (but could be wrong) it should look like this when you are done: V=Table( I(V4), 0mA, 0V, 1mA, 1mV, 2mA, 1.9mV, 3mA, 2.5mV ...) where I(V4) means the current measured through V4 (this is your controlling current), and the pairs that come next, are the (current, voltage) pairs that you measured. I have rarely used the Table() functions in LTspice, so please excuse my inexperience with them. Regards, Andy |
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Re: high frequency MHz and GHz range BJTtransistor or Mosfet
Frank Mead
The 2n918, 2n5179, and the 2n2857 are still alive and well in Mouser database... they are still used... On Wed, Aug 3, 2016 at 4:26 PM, tony@... [LTspice] <LTspice@...> wrote:
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Re: Sub circuit heat dissipation not showing
Helmut,
I know you said "All the Darlington transistors in my examples correctly plot power" But that's not my issue.? I can see the plot/s but I was thinking I would see?"dissipation" in watts as with BJT transistors or other non-sub circuits.? I did download and run the TIP142 sub circuit files. I get the same thing.?"Left click to plot Q10 dissipation. V(c10)*Ix(Q10:C)+V(b10)*Ix(Q10:B)". But as I think I said earlier I was expecting "dissipation = XXXX" at the end of the formula. Interestingly, I noticed that R2 said "dissipation = 0" but when I plot it I see about 850 mW for about 50 us at 50% duty cycle. So wouldn't there be some power dissipation here??? Although the plot (for dissipation) is very useful I guess I was thinking I would see a single value for power dissipation (probably RMS power) for that darlington or even R2. What I am missing something?? Remember I am a beginner and?Thanks, Brad ---In LTspice@..., <helmutsennewald@...> wrote : Hello, The power dissipation of the TIP142 from our Files section will be correctly displayed. TIP_142_test.zip ?? Here are a few more examples. Their power will be displayed too. All the Darlington transistors in my examples correctly plot power.? In therory there are subcircuits possible where LTspice doesn't plot the power due to special combinations of sources internally connected to the pins of a subcircuit. You should upload your files for a test. Best regards, Helmut ? ?? I download and ran the TIP142 sub circuit files. I get the same thing.?"Left click to plot Q10 dissipation. V(c10)*Ix(Q10:C)+V(b10)*Ix(Q10:B)" I can see the plot but I was thinking I would see "dissipation" in watts as with BJT transistors. Interestingly, I noticed that R2 said "dissipation = 0" but when I plot it I see about 850 mW for about 50 us at 50% duty cycle. So wouldn't there be some power dissipation here??? Although the plot (for dissipation) is very useful I guess I was thinking I would see a single value for power dissipation (probably RMS power) for that darlington or even R2. What I am missing something?? Thanks, Brad ---In LTspice@..., <helmutsennewald@...> wrote : Hello, The power dissipation of the TIP142 from our Files section will be correctly displayed. TIP_142_test.zip ?? Here are a few more examples. Their power will be displayed too. All the Darlington transistors in my examples correctly plot power.? In therory there are subcircuits possible where LTspice doesn't plot the power due to special combinations of sources internally connected to the pins of a subcircuit. You should upload your files for a test. Best regards, Helmut ? ? |
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Re: high frequency MHz and GHz range BJTtransistor or Mosfet
There is a standard multi-vibrator circuit that uses the industry workhorse driver the 2N2222 NPN BJT*
and I believe it is listed in the examples files (educational) as "astable.asc". That is a good place as any to start and I have done substitutions using a motorola MRF 901 (LSTPICE's version is a BRF99)..but it still oscillates. You can do both analog and digital from that starting point, ring oscillators as well as CATV amplifiers. Unless you need to model MOSFETs to 40 GHz or related drivers/amplifier on alumina substrates.. ..simple assumptions about phenolic boards should suffice. W. Warren *( cut-off frequency " fc " is around 250 MHz) |
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Re: high frequency MHz and GHz range BJTtransistor or Mosfet
Jim wrote:
"Try a 2N918.?Small signal, but I think it is in the built-in LTspice library." Sadly, this isn't in the standard.bjt file, and it would be long-obsolete anyway, along with the very similar 2N5179 (previously very popular in 1980s HP instruments) and the 2N2857. Fortunately, there are many modern devices from NXP, Infineon and Avago (now Broadcom, used to be HP and Avantek) that are considerably better and available with SPICE models and in proper (surface mount) RF packages. Very few RF designers in the 1980s used SPICE at all, which is why there are few if any manufacturer-supplied models from this era; mostly, design was done with h- or s-parameters, which are linear frequency domain parameters. If you wanted non-linear data, you had to build a test circuit and measure it. Regards, Tony |
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Re: AD630 circuit simulation, no line shown
Hello Tob,
Please watch the SPICE-directives in my uploaded file CircuitAD630_1.zip. It contains a few SPICE-directives to achieve convergence. I also removed the absolute paths of the model files in the symbols.?My uploaded file is in the Temp-folder. By the way there is a nice symbol for the AD630 in the Files section. ? ?? Best regards, Helmut |
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Re: AD630 circuit simulation, no line shown
Hello Tob,
I tested with the latest LTspiceXVII which has been released today. Please ad the following SPICE-directives. .options method=gear .options gmin=1e-10 abstol=1e-10 .options cshunt=1e-16 .tran 0 0.2 0 1u By the way there is a nice symbol and example in our Files section. Best regards, Helmut ? ? |
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Re: Sub circuit heat dissipation not showing
Hello,
The power dissipation of the TIP142 from our Files section will be correctly displayed. TIP_142_test.zip ?? Here are a few more examples. Their power will be displayed too. All the Darlington transistors in my examples correctly plot power.? In therory there are subcircuits possible where LTspice doesn't plot the power due to special combinations of sources internally connected to the pins of a subcircuit. You should upload your files for a test. Best regards, Helmut ? ? |
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Re: AD630 circuit simulation, no line shown
Yes, you are right. It's pretty late here, sorry :/
So my problem is, that I want to simulate the following circuit: [1] Therefore I built up a schematic, which I uploaded in the temp directory as "CircuitAd630": [2] If I hit the simulate button for a transient simulation, there are no lines shown in the diagram, except the ones for the input voltage. Additionally sometimes the simulation needs just a few moments to run and then (without me changing anything) it needs many hours. I tried to locate the error by seperating the two op amps and it looks like the AD630 is the problem here, since the AD8221 works fine, when I simulate it alone by cutting the connections to the righten part of the circuit. Thanks in advance! [1] [2] ? |
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Re: AD630 circuit simulation, no line shown
At 01:51 PM (-0700) 8/3/2016, tob.nagel@... wrote:
---------- Original Message ---------- Hey,---------- End of Original Message ---------- Analog Devices models are notorious for causing agony on LTspice. Try AD633_JT.zip on the Device Models & Subcircuits Page of my website. ...Jim Thompson Web Site: <> |
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Re: Sub circuit heat dissipation not showing
Okay Thanks I tried that and still the same thing. Just displays a formula for power dissipation, but I can left click to plot power.?
---In LTspice@..., <analogspiceman@...> wrote : Hello Brad, Not at my computer right now so I can't check, but maybe you just need to go to the control panel and enable save (subcircuit) currents. |
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Re: high frequency MHz and GHz range BJTtransistor or Mosfet
¿ªÔÆÌåÓýThat ¡°high frequency¡± definition is what is used by the regulators (FCC and their cohorts) to describe transmitted and received signal frequencies. The term is much less precise in actual technical usage. For example: ¡°high frequency amplifier¡± does not characterize it for specific use in the 3-30MHz range, particularly outside of the RF communication arena.Jim James Wagner Oregon Research Electronics
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Re: I want to know
llgveka?wrote: ? ?"I want to understand the operation of a switch made up of a P_MOS and a N_MOS in parallels" You can read about it here: I looked for the same page in French, but apparently there is not one.? I am sure the information must be available in all languages, but the name might be different in French. ? ?"and how to assemble them to convert an analogical signal into a numerical signal." I don't know what that means.? I don't think you can combine only switches to make an Analog-to-Digital (A/D) converter.? I think you need to use other kinds of circuits to do that. If you need help to understand PMOS and NMOS transistors in a transmission gate switch, then you might not understand how to make an A/D converter yet. ? Keep studying! Andy |
aurvii
Tony Casey
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