hello i would like to design a single ended output transformer with the SJDP170R1400 but first i would like to create a spice model with this device and also i would like to how to get the transconductance just reading the datasheet thanks in advance
P.D: I do not know so much of electronics but I am in the way of learning so any help could be good.
P.D: I do not know so much of electronics but I am in the way of learning so any help could be good.
These are switching devices, so that is not the mfr biggest interest.
Depends strongly on the bias point, see figure 5 here.
Depends strongly on the bias point, see figure 5 here.
I searched out the data sheet linked below and Figure 5 shows transconductance, which is its slope--- i.e. around 1.25A/V
https://www.rlocman.ru/i/File/dat/SemiSouth/0/SJDP170R1400.pdf
Just saw rayma post. 🙂
https://www.rlocman.ru/i/File/dat/SemiSouth/0/SJDP170R1400.pdf
Just saw rayma post. 🙂
Thanks for the information I was wondering Wich it's better performance between this and cree c2m1000170a or the ixtp01n100d for the task of been an power mosfet single ended with OT
Hi claulogic,
A model for the SJDP170R1400. Not possible with the standard nJFET model. A more sophisticated model is needed like this one for the UnitedSiC jfet here for the UJ3N065080K3S https://www.diyaudio.com/community/threads/better-power-mosfet-models-in-ltspice.266655/post-6169519
Here's a rough model for the SJDP170R1400 using the VDMOS:
.model SJDP170R1400 VDMOS (Vto=-4.5 Kp=10
This model doesn't have temp.co's and no gate current (jFETs have GD and GS gate diodes, MOSFETs do not) . But OK to get started. BTW the datasheet lacks temp.co info.
Re: C2M1000170D is an enhancement MOSFET:
.model C2M1000170D VDMOS (Rg=3 Vto=5.8 Kp=0.28
It doesn't have temp.co's. It has a high value for Ksubthres because the low current region (were you will probably use it) has an extended exponential region.
I can't comment on which of these are more suited to your amp. Try some simulations. All the best.
A model for the SJDP170R1400. Not possible with the standard nJFET model. A more sophisticated model is needed like this one for the UnitedSiC jfet here for the UJ3N065080K3S https://www.diyaudio.com/community/threads/better-power-mosfet-models-in-ltspice.266655/post-6169519
Here's a rough model for the SJDP170R1400 using the VDMOS:
.model SJDP170R1400 VDMOS (Vto=-4.5 Kp=10
- Rs=0.4 Ksubthres=0.35 Mtriode=0.4 Rd=0.7
- Cgdmax=30p Cgdmin=15p a=0.35 Cgs=30p Cjo=30p
- Vds=1700 Ron=1400m Qg=0.5nC mfg=IH2303prov)
This model doesn't have temp.co's and no gate current (jFETs have GD and GS gate diodes, MOSFETs do not) . But OK to get started. BTW the datasheet lacks temp.co info.
Re: C2M1000170D is an enhancement MOSFET:
.model C2M1000170D VDMOS (Rg=3 Vto=5.8 Kp=0.28
- Rs=0.1 Ksubthres=1.5 Rd=0.4
- Cgdmax=100p Cgdmin=20p a=1 Cgs=450p Cjo=150p m=0.4 VJ=0.75
- Rb=0.4 Is=1n N=5 Eg=4.5 Vds=1700 Ron=1000m Qg=22n mfg=IH2303)
It doesn't have temp.co's. It has a high value for Ksubthres because the low current region (were you will probably use it) has an extended exponential region.
I can't comment on which of these are more suited to your amp. Try some simulations. All the best.
ok thax for the information im going to explain what I would like to do, I would like to do a guitar amp using transistor with OT single ended and push pull theres a guy who made it possible with the 2sk216 but he refer to che the transocnductance input capacitance and power dissipation I see the model that you chec in there has a good performance in temp but the input capacitance is high probably need to be made with low voltage right?
Hi claulogic,
Re: power FET input capacitance. It depends on how you drive the FET. If you use a follower stage power FET input capacitance is made a non issue.
Re: transconductance of the power FET. When using an OT the transconductance of any power FET should be adequate even with the low bias currents.
More important issues are 1) thermal biasing stability, and 2) Safe Operating Area, and 3) transformers can generate very high voltage spikes, so some spike protection would be good and use a generous safety derating factor. Tubes are robust in this regard. 😉
You mention the 2SK216 example but I couldn't find any posts on this device. Can you provide a link or a basic circuit you have in mind and some members may offer to assist.
Sorry, I only have experience with guitar amps using lateral MOSFETs which are transformerless output. (In my school days I made some 5W SE and push-pull tube amps). Custom output transformers above 10W can be quite expensive for DIY, although I have heard of using microwave transformers🙂.
Re: power FET input capacitance. It depends on how you drive the FET. If you use a follower stage power FET input capacitance is made a non issue.
Re: transconductance of the power FET. When using an OT the transconductance of any power FET should be adequate even with the low bias currents.
More important issues are 1) thermal biasing stability, and 2) Safe Operating Area, and 3) transformers can generate very high voltage spikes, so some spike protection would be good and use a generous safety derating factor. Tubes are robust in this regard. 😉
You mention the 2SK216 example but I couldn't find any posts on this device. Can you provide a link or a basic circuit you have in mind and some members may offer to assist.
Hi IanHegglun
KMG its a great desingner on transistor amps they make a jcm 800 solid state with output transformer so the only thing im trying to find a transistor that could replace de 2sk216 it out of production im sharing some of his work here and theres also a a jfet version of an amp with a commecial audio output transformrer
KMG its a great desingner on transistor amps they make a jcm 800 solid state with output transformer so the only thing im trying to find a transistor that could replace de 2sk216 it out of production im sharing some of his work here and theres also a a jfet version of an amp with a commecial audio output transformrer