"Jellybean" HV low power MOSFET

Started by Ralph Barone in sci.electronics.design8 years ago 8 replies

Can anybody suggest a cheap, easily obtainable > = 400 V, < 2A thru hole MOSFET, preferably one that's designed more for analog use than for...

Can anybody suggest a cheap, easily obtainable > = 400 V, < 2A thru hole MOSFET, preferably one that's designed more for analog use than for sub-ns switching. Thanks. I'm looking to squeeze a cathode follower into an existing vacuum tube amp and adding one MOSFET is easier than adding half a 12AT7.


"high voltage" MOSFET

Started by bitrex in sci.electronics.design3 years ago 20 replies

Looking for a MOSFET with a 100 or 150-200 (would be better), Vds N-channel that can switch a couple amps at a couple MHz, preferably in D-pak...

Looking for a MOSFET with a 100 or 150-200 (would be better), Vds N-channel that can switch a couple amps at a couple MHz, preferably in D-pak or something for ease of compact Manhattan-prototyping. MOSFET-selection is always problematic for me there are so many and the parameters like temperature de-rating and how fast you can switch it at a given temperature all interact so it's hard ...


A quiet forward converter likes only one MOSFET -- why?

Started by Piotr Wyderski in sci.electronics.design3 years ago 18 replies

Hi, I have been trying to build a low-power multiple-output converter that has no regulation at the secondary side. Its purpose is to power...

Hi, I have been trying to build a low-power multiple-output converter that has no regulation at the secondary side. Its purpose is to power many floating MOSFET drivers, so a reasonably too low voltage is not a problem, but to high certainly is. Particularly, the experiments involved powering a mock-up SiC MOSFET driver with +15/-3.3V rails. Therefore, the smoothness of the transition ...


ltspice -- body effect and other matters

Started by Michael Robinson in sci.electronics.design12 years ago 11 replies

I need to be able to model a mosfet with values of L, W, Vth, Kprime, lamba and gamma, and I'm trying to figure out how to do this with...

I need to be able to model a mosfet with values of L, W, Vth, Kprime, lamba and gamma, and I'm trying to figure out how to do this with LTSpice. Looking at ltspice mosfet models, they don't have a separate value for K. They have Cgs, W and L. K is a function of Cgs, W, L, and electron mobility. So I could sort of kluge my own mosfet model by choosing Cgs so that K comes out just right. ...


New depletion MOSFET - BSS126

Started by Anonymous in sci.electronics.design2 years ago 8 replies

I happened upon this today while looking at other things... BSS126 - 600V, 500 ohms, Idss =...

I happened upon this today while looking at other things... BSS126 - 600V, 500 ohms, Idss = 21mA. https://www.infineon.com/cms/en/product/power/mosfet/60v-600v-n-channel-depletion-mode-mosfet/ I've not used any depletion MOSFETs but I know some of you guys are fans (and I hope to join the fan club someday too)! Cheers, James Arthur


Super low power isolated MOSFET driver

Started by Piotr Wyderski in sci.electronics.design3 years ago 25 replies

Hi, I need to slowly drive a high-voltage high-side MOSFET in a 5kV isolated setup. This use case reminds an electronic fuse: the MOSFET is...

Hi, I need to slowly drive a high-voltage high-side MOSFET in a 5kV isolated setup. This use case reminds an electronic fuse: the MOSFET is expected to be almost always ON, but the driver needs to start in an OFF condition. Generally the answer would be Si8261, but it requires ~50mW. So I have devised a much less energy hungry driver based on a tiny 1:1 bipolar drive pulse transformer ...


75332P MOSFET drain connected to which battery terminal?

Started by John Doe in sci.electronics.design11 years ago 18 replies

I have a 75332P MOSFET on a cordless drill controller heatsink. I guess it's part of a pulse width modulator. The drain (flange) connects...

I have a 75332P MOSFET on a cordless drill controller heatsink. I guess it's part of a pulse width modulator. The drain (flange) connects directly to one of the battery terminals. Does the MOSFET drain go directly to the battery minus/ground terminal? Or does it go to the battery plus terminal? Thanks. -- My application... I'm desperately trying to develop a better inline ...


Fail to amplify 27mhz rf using mosfet IRF843

Started by Anonymous in sci.electronics.design6 years ago 20 replies

I found old mosfet transistor IRF843, using 20k and 70k resistor, i manage to set the voltage at transistor gate to 3.9 volt and using 1uF to...

I found old mosfet transistor IRF843, using 20k and 70k resistor, i manage to set the voltage at transistor gate to 3.9 volt and using 1uF to channel the 27mhz rf signal to the transistor gate, i manage to get an audio from 8ohm speaker connected to the transistor drain. I'm using about 5.3 volt power supply from transformer. The audio is loud and clear. The mosfet gate can received


Faster than 2n7002

Started by Anonymous in sci.electronics.design7 years ago 29 replies

Cool part. 20V enhancement N-ch MOSFET. Vgs.th(100uA)

Cool part. 20V enhancement N-ch MOSFET. Vgs.th(100uA)


Negative VG for SiC MOSFETs

Started by Piotr Wyderski in sci.electronics.design4 years ago 3 replies

The datasheet of C3M0065090J says its VGSmax is -4/+15V, but Note (2) says the "MOSFET can also safely operate at 0/15V." What is...

The datasheet of C3M0065090J says its VGSmax is -4/+15V, but Note (2) says the "MOSFET can also safely operate at 0/15V." What is "safely" supposed to mean? As safely as a Si MOSFET with no negative gate voltage? Could you please share your opinion on SiC device driving based on your actual experience? Best regards, Piotr


MOSFET WTF

Started by Tim Williams in sci.electronics.design5 years ago 21 replies

VDMOS nonlinear capacitance is modeled in terms of Vgd. Too bad a real MOSFET doesn't show a steplike change in Ciss as Vgd changes sign. ...

VDMOS nonlinear capacitance is modeled in terms of Vgd. Too bad a real MOSFET doesn't show a steplike change in Ciss as Vgd changes sign. (This is easily demonstrated with the gate charge test circuit, watching the waveform at low Vdd. The cutoff slope depends only on Vds, not Vgd.) So many decades of bullshit to sift through... Tim -- Seven Transistor Labs, LLC Electrical E...


op-amp-controlled MOSFET cucrrent-source

Started by Winfield Hill in sci.electronics.design3 years ago 23 replies

Have you seen an analysis of the classic op-amp-controlled MOSFET current-source? I needed this for a design, plus I'd like to squeeze it...

Have you seen an analysis of the classic op-amp-controlled MOSFET current-source? I needed this for a design, plus I'd like to squeeze it into the x-Chapters, before the mid-August printing deadline. https://www.dropbox.com/s/nednxac2bykld8q/opamp-MOSFET_current-source.pdf?dl=1 In the formulas, I assume the opamp's output signal is controlled by Vin-Vs and R2 C2. I'm still ch...


Application Note 948 - Linear Power Amplifier Using Complementary HEXFETs

Started by Anonymous in sci.electronics.design14 years ago 15 replies

Fascinating reading: http://www.irf.com/technical-info/appnotes/an-948.pdf (found from here: ...

Fascinating reading: http://www.irf.com/technical-info/appnotes/an-948.pdf (found from here: http://sound.westhost.com/articles/hexfet.htm) I've heard that the 2SK1058 is superior for audio, and is the only MOSFET spec'ed in Slone's book, but that this MOSFET is currently now unobtanium. What is the purpose of the inductor L1 (3 uH, air core) in series with the speaker? Any commen...


MOSFET: why is it called Miller plateau?

Started by Piotr Wyderski in sci.electronics.design3 years ago 32 replies

Hi, many papers explain the MOSFET's gate-source charging curve, especially the plateau part of it, by the Miller effect. Sometime this is...

Hi, many papers explain the MOSFET's gate-source charging curve, especially the plateau part of it, by the Miller effect. Sometime this is even briefly called "the Miller plateau". But why? To my understanding, the Miller effect is of entirely dynamic nature and is simply caused by the negative feedback introduced by parasitic capacitances between the input and the output of an inverti...


fet for automatic gain control?

Started by Hul Tytus in sci.electronics.design9 years ago 31 replies

sci.electronics.design fet for automatic gain control? Any suggestions for an enhancement mode mosfet to serve as a variable resistence...

sci.electronics.design fet for automatic gain control? Any suggestions for an enhancement mode mosfet to serve as a variable resistence element in an automatic gain control type circuit? Power involved is a bare whisper; worst case voltage is probably 30 volts. There may well be a better remidy than an mosfet, but it looks good at this point. Hul


Power MOSFET SPICE modelling

Started by Glenn in sci.electronics.design9 years ago 2 replies

How can they SPICE model two distinct serially connected resistors (Rls, Rcs - respectively Rll, Rcl) inside a power MOSFET? Are they kidding us...

How can they SPICE model two distinct serially connected resistors (Rls, Rcs - respectively Rll, Rcl) inside a power MOSFET? Are they kidding us ;-) If so is that useful in the model?: A Low-Cost Class-E Power Ampli?er with Sine-Wave Drive - Caltech: http://www.its.caltech.edu/~mmic/reshpubindex/papers/ClassE.pdf (pdf-page 3) - Is it possible (how?) to measure the internal paras


fast, small low-capacitance zener to protect MOSFET gates

Started by Winfield Hill in sci.electronics.design4 years ago 28 replies

I became discouraged of finding a suitable low-capacitance zener to protect the MOSFET gates in my high-voltage amplifier designs. (The...

I became discouraged of finding a suitable low-capacitance zener to protect the MOSFET gates in my high-voltage amplifier designs. (The protection may be optional, but one sleeps better with it in place.) Even the 50uA-rated low-current zener diodes are in fact larger-die types, with high capacitance. For example, the 7.5-volt MMSZ4693 has about 130pF at zero volts. My solution was to us...


MOSFET "Backwards" Current / Motor anti-generate

Started by Tim Wescott in sci.electronics.design10 years ago 19 replies

In 4-quadrant switching amplifiers, it's quite common to run current through a MOSFET "backwards" when it is on -- i.e., to run an NMOS with...

In 4-quadrant switching amplifiers, it's quite common to run current through a MOSFET "backwards" when it is on -- i.e., to run an NMOS with the current traveling from source to drain, instead of drain to source. Yet all the data sheets only show 1st-quadrant conduction, with current (for an NMOS) running from drain to source. Which boils down to my real problem: I'm working on a motor...


If you can't find a MOSFET big enough

Started by Piotr Wyderski in sci.electronics.design2 years ago 4 replies

Some people seem to have way too much spare time: https://www.youtube.com/watch?v=So-6lgmVhA0 Best regards, Piotr

Some people seem to have way too much spare time: https://www.youtube.com/watch?v=So-6lgmVhA0 Best regards, Piotr


Depletion-mode P-channel MOSFET

Started by Piotr Wyderski in sci.electronics.design4 years ago 6 replies

Why such a thing does not exist in nature? I'd find several applications of such a beast. Of a P-channel complementary to LND150,...

Why such a thing does not exist in nature? I'd find several applications of such a beast. Of a P-channel complementary to LND150, especially. Best regards, Piotr