On Tue, 29 Apr 2014 20:13:00 +0100, "Kevin Aylward" <ExtractkevinRemove@kevinaylward.co.uk> wrote:>"Maynard A. Philbrook Jr." wrote in message >news:MPG.2dc8b77542a1a04e989899@news.eternal-september.org... > >In article <op.xe0aifd22cx0wh@ajm>, robert.a.macy@gmail.com says... >> >> On Sun, 27 Apr 2014 09:27:27 -0700, Jim Thompson >> <To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote: >> >> > I'm behaviorally modeling a _system_ that includes the discrete device >> > Supertex VP2450. >> > >> > At the Supertex/Microchip site, it says no Spice model available :-) >> > >> > Does anyone know of a model? >> > >> > Thanks! >> > >> > ...Jim Thompson >> >> >> I didn't see it anywhere in the 35MB of Alex Bordodunov's models, but he >> might have one. Did you email him? > >>I am no model expert, let alone understanding some of the spice >>parameters that are not even seen in the data base models, but I came up >>with this using supertex PDF file, as vague as it was. Lots of items not >>specified in it and some that are, I don't see where to apply them in >>spice, because like I said, I ain't no model expert. >> I ran this using their test jig and the charts to do some compares. > >.model VP2450 VDMOS(pchan Rg= 3 Rd=15 Rs=15 Vto=-2.0 BV=-500 Kp=320 >Cgs=190p Is=1e-30 CgdMax= 75p) > >Ahmm.... Is is a tad small, and may cause convergence problems. A 1uX1u >diode junction will be of the order of < 1e-18, usually > >Bigger discrete devices might be hitting 1e-15, or thereabouts > >Kevin Aylward B.Sc. >www.kevinaylward.co.uk >www.anasoft.co.uk - SuperSpiceA published model I found had AD, AS=1. Scratched butt, guesstimated 1u, it then simulated OK. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
VP2450 Spice Model
Started by ●April 27, 2014
Reply by ●April 29, 20142014-04-29
Reply by ●April 29, 20142014-04-29
In article <zuCdnUA8O7QkZMLOnZ2dnUVZ8mWdnZ2d@bt.com>, ExtractkevinRemove@kevinaylward.co.uk says...> > "Maynard A. Philbrook Jr." wrote in message > news:MPG.2dc8b77542a1a04e989899@news.eternal-september.org... > > In article <op.xe0aifd22cx0wh@ajm>, robert.a.macy@gmail.com says... > > > > On Sun, 27 Apr 2014 09:27:27 -0700, Jim Thompson > > <To-Email-Use-The-Envelope-Icon@on-my-web-site.com> wrote: > > > > > I'm behaviorally modeling a _system_ that includes the discrete device > > > Supertex VP2450. > > > > > > At the Supertex/Microchip site, it says no Spice model available :-) > > > > > > Does anyone know of a model? > > > > > > Thanks! > > > > > > ...Jim Thompson > > > > > > I didn't see it anywhere in the 35MB of Alex Bordodunov's models, but he > > might have one. Did you email him? > > >I am no model expert, let alone understanding some of the spice > >parameters that are not even seen in the data base models, but I came up > >with this using supertex PDF file, as vague as it was. Lots of items not > >specified in it and some that are, I don't see where to apply them in > >spice, because like I said, I ain't no model expert. > > I ran this using their test jig and the charts to do some compares. > > .model VP2450 VDMOS(pchan Rg= 3 Rd=15 Rs=15 Vto=-2.0 BV=-500 Kp=320 > Cgs=190p Is=1e-30 CgdMax= 75p) > > Ahmm.... Is is a tad small, and may cause convergence problems. A 1uX1u > diode junction will be of the order of < 1e-18, usually > > Bigger discrete devices might be hitting 1e-15, or thereaboutsTrue, but like I said, I am not an expert at this but, the PDF for the component claims a -1.8V forward drop on the body diode, if you can believe that, unless I misunderstood something.. http://www.supertex.com/pdf/datasheets/VP2450.pdf So at 100mA 1e-30 31 was hitting close to home after running some sims and comparing values. Maybe some one else can get it closer.. Jamie
Reply by ●April 30, 20142014-04-30
"Maynard A. Philbrook Jr." <jamie_ka1lpa@charter.net> wrote in message news:MPG.2dca19a467bde55798989d@news.eternal-september.org...> True, but like I said, I am not an expert at this but, the PDF for the > component claims a -1.8V forward drop on the body diode, if you can > believe that, unless I misunderstood something.. > > http://www.supertex.com/pdf/datasheets/VP2450.pdf > > So at 100mA 1e-30 31 was hitting close to home after running some sims > and comparing values. > > Maybe some one else can get it closer..Hmm. Silicon is silicon. It's still going to turn on around 0.6V -- it would be amazing physics otherwise. That would suggest ESR around 1.2V/100mA = 12 ohms max. I forget if the MOS model includes RD/RS parameters, but these can be added externally if not. IS can then be specified based on leakage and lower current behavior (it should be fairly "ideal diode" under 10mA). Not much to say about one datapoint unfortunately. And it's a maximum, not typical, and certainly not plotted. How lazy. Probably a good idea measuring a few. Tim -- Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com
Reply by ●April 30, 20142014-04-30
"Maynard A. Philbrook Jr." wrote in message news:MPG.2dca19a467bde55798989d@news.eternal-september.org...> >> .model VP2450 VDMOS(pchan Rg= 3 Rd=15 Rs=15 Vto=-2.0 BV=-500 Kp=320 >> Cgs=190p Is=1e-30 CgdMax= 75p) > >> Ahmm.... Is is a tad small, and may cause convergence problems. A 1uX1u >> diode junction will be of the order of < 1e-18, usually > > Bigger discrete devices might be hitting 1e-15, or thereabouts >True, but like I said, I am not an expert at this but, the PDF for the >component claims a -1.8V forward drop on the body diode, if you can >believe that, unless I misunderstood something..They possibly made the 101 error of not setting N in exp(Vbe/Vt.N) to its correct value, from its default of 1, or possibly they set the diode resistance incorrectly. For example, to model LEDs, N might be 2.5. to get the several volts that it has. "Is" is the reverse leakage current of a diode. No way is it 1e-30 amps! Kevin Aylward B.Sc. www.kevinaylward.co.uk www.anasoft.co.uk - SuperSpice
Reply by ●April 30, 20142014-04-30
In article <crSdnQkJJKt3svzOnZ2dnUVZ7sSdnZ2d@bt.com>, ExtractkevinRemove@kevinaylward.co.uk says...> > "Maynard A. Philbrook Jr." wrote in message > news:MPG.2dca19a467bde55798989d@news.eternal-september.org... > > > > >> .model VP2450 VDMOS(pchan Rg= 3 Rd=15 Rs=15 Vto=-2.0 BV=-500 Kp=320 > >> Cgs=190p Is=1e-30 CgdMax= 75p) > > > >> Ahmm.... Is is a tad small, and may cause convergence problems. A 1uX1u > >> diode junction will be of the order of < 1e-18, usually > > > > Bigger discrete devices might be hitting 1e-15, or thereabouts > >True, but like I said, I am not an expert at this but, the PDF for the > >component claims a -1.8V forward drop on the body diode, if you can > >believe that, unless I misunderstood something.. > > They possibly made the 101 error of not setting N in exp(Vbe/Vt.N) to its > correct value, from its default of 1, or possibly they set the diode > resistance incorrectly. > > For example, to model LEDs, N might be 2.5. to get the several volts that it > has. > > "Is" is the reverse leakage current of a diode. No way is it 1e-30 amps! > > Kevin Aylward B.Sc. > www.kevinaylward.co.uk > www.anasoft.co.uk - SuperSpiceOk. .model VP2450 VDMOS(pchan Rg= 3 Rd=5 Rs=9 Vto=-2.0 BV=-500 N=2.3 Kp= 320 Cgs=195p CgdMax=75p) I think there as a reason where there is no model out there for this.
