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DanTherm model (SOAtherm)

jammanfr All Messages By This Member #82028 ??? Hello, I'd like to use the SOAtherm with an user defined MOSFET. Unfortunately, i can't get the relation between the DanTherm model and the manufacturer model. Example: FDB3632 DanTherm model: R6=2.42E-03 C6=1.21E-03 R5=2.95E-02? C5=6.20E-05 R4=2.03E-01? C4=2.69E-03 R3=2.34E-01? C3=3.21E-02 R2=5.94E-02? C2=1.81E-01 R1=2.47E-03? C1=8.25E-08 Manufacturer model: CTHERM1 TH 6 7.5e-3 CTHERM2 6 5 8.0e-3 CTHERM3 5 4 9.0e-3 CTHERM4 4 3 2.4e-2 CTHERM5 3 2 3.4e-2 CTHERM6 2 TL 6.5e-2 RTHERM1 TH 6 3.1e-4 RTHERM2 6 5 2.5e-3 RTHERM3 5 4 2.2e-2 RTHERM4 4 3 8.1e-2 RTHERM5 3 2 1.35e-1 RTHERM6 2 TL 1.5e-1 Does somebody know the relation between these values ? Thanks, Marc
Andy All Messages By This Member #82030 Marc wrote: ? ?"I'd like to use the SOAtherm with an user defined MOSFET. ? ? ... ? ??Does somebody know the relation between these values ?" I don't understand your question. Do you know what the things that you posted are? The first one: ? ?"R6=2.42E-03 C6=1.21E-03 R5=2.95E-02? C5=6.20E-05 R4=2.03E-01? C4=2.69E-03 R3=2.34E-01? C3=3.21E-02 R2=5.94E-02? C2=1.81E-01 R1=2.47E-03? C1=8.25E-08" is a list of resistor and capacitor values.? But there is nothing to show how they are connected.? Where did you get that from? The second one: ? ?"CTHERM1 TH 6 7.5e-3 ? ?? ? CTHERM2 6 5 8.0e-3 ? ? ?? CTHERM3 5 4 9.0e-3 ? ? ?? CTHERM4 4 3 2.4e-2 ? ? ?? CTHERM5 3 2 3.4e-2 ? ? ?? CTHERM6 2 TL 6.5e-2 ? ? ?? RTHERM1 TH 6 3.1e-4 ? ? ?? RTHERM2 6 5 2.5e-3 ? ? ?? RTHERM3 5 4 2.2e-2 ? ?? ? RTHERM4 4 3 8.1e-2 ? ? ?? RTHERM5 3 2 1.35e-1 ? ? RTHERM6 2 TL 1.5e-1" is a SPICE subcircuit.? It has both the values (e.g., 7.5e-3) and how they are interconnected. Both methods use a SPICE circuit to represent the thermal characteristics of something.? How it gets used, well that depends on what the other devices are in your SPICE circuit. If you want to understand the differences between the two methods, you could look at the step response of each circuit.? They might be similar, even if the values of the R's and C's within them, are not the same. I can't answer your question because there is no clear question. Regards, Andy
jammanfr All Messages By This Member #82031 Thank you for you answer Andy ! The first list comes from the file SOAtherm-NMOS.lib (in ./sub). It's the model created by . The second one comes from the datasheet of the MOSFET : page 10 If you put a SOAtherm component (F2 key in LTspice, and SOAtherm), and right click on it, you'll have a list of thermal model included in LTspice (the ones that are in the SOAtherm-NMOS.lib) My aim is to add a thermal model of another Mosfet say : the IRF740. My approach was to compare the thermal parameter (R's and C's) of the file in LTspice (SOAtherm-NMOS.lib) to the parameters given by the manufacturer to create my own model. But they're not the same ! Maybe the schematic is not the same (how the R's & C's are placed) ? It is documented ? So my question is : how got his values (R's & C's) since they are different from the datasheet ? I hope my question is clearer. I tried to simulate both models has suggested, but i didn't find the same results. I don't know if we can join a file so I copy paste the whole .asc: Version 4 SHEET 1 880 680 WIRE 0 -112 -48 -112 WIRE 96 -112 80 -112 WIRE 112 -112 96 -112 WIRE 208 -112 192 -112 WIRE 224 -112 208 -112 WIRE 320 -112 304 -112 WIRE 336 -112 320 -112 WIRE 432 -112 416 -112 WIRE 448 -112 432 -112 WIRE 544 -112 528 -112 WIRE 560 -112 544 -112 WIRE 672 -112 640 -112 WIRE 0 -32 0 -112 WIRE 0 -32 -48 -32 WIRE 96 -32 96 -112 WIRE 96 -32 64 -32 WIRE 112 -32 96 -32 WIRE 208 -32 208 -112 WIRE 208 -32 176 -32 WIRE 224 -32 208 -32 WIRE 320 -32 320 -112 WIRE 320 -32 288 -32 WIRE 336 -32 320 -32 WIRE 432 -32 432 -112 WIRE 432 -32 400 -32 WIRE 448 -32 432 -32 WIRE 544 -32 544 -112 WIRE 544 -32 512 -32 WIRE 560 -32 544 -32 WIRE 640 -32 640 -112 WIRE 640 -32 624 -32 WIRE 672 -32 640 -32 WIRE 0 112 -48 112 WIRE 96 112 80 112 WIRE 112 112 96 112 WIRE 208 112 192 112 WIRE 224 112 208 112 WIRE 320 112 304 112 WIRE 336 112 320 112 WIRE 432 112 416 112 WIRE 448 112 432 112 WIRE 544 112 528 112 WIRE 560 112 544 112 WIRE 672 112 640 112 WIRE 0 192 0 112 WIRE 0 192 -48 192 WIRE 96 192 96 112 WIRE 96 192 64 192 WIRE 112 192 96 192 WIRE 208 192 208 112 WIRE 208 192 176 192 WIRE 224 192 208 192 WIRE 320 192 320 112 WIRE 320 192 288 192 WIRE 336 192 320 192 WIRE 432 192 432 112 WIRE 432 192 400 192 WIRE 448 192 432 192 WIRE 544 192 544 112 WIRE 544 192 512 192 WIRE 560 192 544 192 WIRE 640 192 640 112 WIRE 640 192 624 192 WIRE 672 192 640 192 FLAG -48 272 0 FLAG 672 192 0 FLAG -48 48 0 FLAG 672 -32 0 SYMBOL res 96 96 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R1 SYMATTR Value 0.31m SYMBOL cap 64 176 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C1 SYMATTR Value 7.5m SYMBOL res 208 96 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 2.5m SYMBOL cap 176 176 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C2 SYMATTR Value 8m SYMBOL res 320 96 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R3 SYMATTR Value 22m SYMBOL cap 288 176 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C3 SYMATTR Value 9m SYMBOL res 432 96 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R4 SYMATTR Value 81m SYMBOL cap 400 176 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C4 SYMATTR Value 24m SYMBOL res 544 96 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R5 SYMATTR Value 135m SYMBOL cap 512 176 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C5 SYMATTR Value 34m SYMBOL res 656 96 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R6 SYMATTR Value 150m SYMBOL cap 624 176 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C6 SYMATTR Value 65m SYMBOL current -48 272 R180 WINDOW 0 24 80 Left 2 WINDOW 3 24 0 Left 2 WINDOW 123 24 -28 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName I1 SYMATTR Value 0 SYMATTR Value2 AC 1 SYMBOL res 96 -128 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R7 SYMATTR Value 2.42m SYMBOL cap 64 -48 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C7 SYMATTR Value 1.21m SYMBOL res 208 -128 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R8 SYMATTR Value 29.5m SYMBOL cap 176 -48 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C8 SYMATTR Value 62? SYMBOL res 320 -128 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R9 SYMATTR Value 0.203 SYMBOL cap 288 -48 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C9 SYMATTR Value 2.69m SYMBOL res 432 -128 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R10 SYMATTR Value 0.234 SYMBOL cap 400 -48 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C10 SYMATTR Value 32.1m SYMBOL res 544 -128 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R11 SYMATTR Value 59.4m SYMBOL cap 512 -48 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C11 SYMATTR Value 0.181 SYMBOL res 656 -128 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R12 SYMATTR Value 2.47m SYMBOL cap 624 -48 R90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName C12 SYMATTR Value 82.5n SYMBOL current -48 48 R180 WINDOW 0 24 80 Left 2 WINDOW 3 24 0 Left 2 WINDOW 123 24 -28 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName I2 SYMATTR Value 0 SYMATTR Value2 AC 1 TEXT -82 320 Left 2 !.ac dec 1k 0.1 100k
Helmut Sennewald All Messages By This Member #82033 Hello jammanfr, You have overlooked that th RC-models use a different structure. Please take a look to my uploaded file. soa_therm1a.asc ? ? Best regards, Helmut
Helmut Sennewald All Messages By This Member #82036 Hello, I just found the corerct name for the thermal RC ladder models.They are named Foster and Cauer model. ... You can find a lot more literature in the Internet with Google. Best regards, Helmut
jammanfr All Messages By This Member #82056 Thank you very much Helmut ! I managed to convert the values of the Foster ladder to the Cauer ladder. The result can be seen here : ? The bode diagram of the Cauer ladder (resulting from the conversion) is exactly the same as the Foster ladder, however, the DanTherm is not exactly the same as the two others. I think i will do with that. Gratefully, Marc
Helmut Sennewald All Messages By This Member #82057 Hello Marc, Thanks a lot for this link to Matlab. The transformation looks perfect in your uploaded file. Best regards, Helmut
[email protected] #89956 I just discovered the LT application video on the SOAtherm-NMOS device. ?This looks like a really neat function. ?Searching the archives comes up with a thread from last year about converting datasheet information into SOAtherm models, but it looks like MatLab is needed. ?I'm not MatLab fluent (used it once, 20 years ago), but I'd like to model the FETs I'm using in my designs. ?Does anybody have any hints/tricks/recipes for determining the values of the entries in Dan Eddleman's DanTherm model? ?The library has these elements that determine the thermal model: ? * The following two lines are customized for each DanTherm model *? .param Tambient=85 RthetaJA=50 Cheatsink=0? .param Imult=1.00E+01 Iexponent=3.00E-01 R6=3.18E-02 C6=1.77E-04 R5=1.01E-01 ?C5=2.77E-04 R4=2.74E-01 ?C4=1.60E-03 R3=8.49E-01 ?C3=8.83E-03 R2=7.34E-02 ?C2=3.30E-03 R1=1.05E-03 ?C1=1.82E-03 Do I need to contact Dan to get his modeling information? Thanks, Carl
Nicholas Jankowski All Messages By This Member #89957 I don't know anything about the model, but you could see if the MATLAB code runs under GNU Octave. It's a free open source tool meant to be m-code compatible.
i 5 All Messages By This Member #102020 Hello, R and C values, at least for NXP, are provided in the Documentation tab of the MOSFET used (in a form of Foster ladder). My questions are: 1. Is DanTherm model populated with Foster or?Cauer values? 2. How are?Imult and?Iexponent values obtained? Regards
[email protected] All Messages By This Member #159148 Hello to all, I just discovered the discussion. I would be very interested by the SOATherm simulation. I found it crazy that this is almost unusable as there is almost no documentation on it. Does anyone have any news ? Thanks a lot in advance.

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