Astable multivibrator with MOSFET SPICE model

Started by Anonymous in sci.electronics.design6 years ago 16 replies

Could some electronics guru point me to a working(i.e., correctly simulates) astable multivibrator SPICE model with MOSFET only. I have two...

Could some electronics guru point me to a working(i.e., correctly simulates) astable multivibrator SPICE model with MOSFET only. I have two working BJT based astable multivibrator SPICE models. However, my MOSFET based astable multivibrator model, works as per hand calculation, but shows no oscillations with a regular SPICE .TRAN analysis. I have tried the standard SPICE tricks, as havi...


New power MOSFET makes solid state microwave oven possible

Started by Jan Panteltje in sci.electronics.design9 years ago 57 replies

New power MOSFET makes solid state microwave oven possible: In German: ...

New power MOSFET makes solid state microwave oven possible: In German: http://www.heise.de/newsticker/meldung/Mikrowelle-ohne-Magnetron-1624974.html It tsays 'Midea' will make a 600W microwave oven with these MOSFETs, about same efficiency as a normal one, but switchmode power suplly, so probably a lot lighter. The MOSFET specs: http://www.freescale.com/webapp/sps/site/prod_summary.js...


PV MOSFET driver reliability

Started by Piotr Wyderski in sci.electronics.design7 years ago 42 replies

How reliable such devices are in real life? The most extreme, yet typical use case: a constantly opened N MOSFET (i.e. it should be closed only...

How reliable such devices are in real life? The most extreme, yet typical use case: a constantly opened N MOSFET (i.e. it should be closed only during exceptional scenarios), which implies constantly energized LED inside the coupler. For many^2 years. Is it an obvious no-go? One alternative is a transformer-coupled full wave rectifier driven by an oscillator I already have. Seems to be bul...


Optically Coupled MOSFet ??

Started by Jim Thompson in sci.electronics.design7 years ago 6 replies

Does anyone make an optically coupled MOSFet, Ron around 25 Ohms? All I can find are relay equivalent devices with loads of capacitance. ...

Does anyone make an optically coupled MOSFet, Ron around 25 Ohms? All I can find are relay equivalent devices with loads of capacitance. ...Jim Thompson -- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | ...


Spice mosfet dissipation

Started by John Larkin in sci.electronics.design7 years ago 8 replies

Is there an easy way to get a graph of mosfet power dissipation vs time, or, alternately, to compute the dissipation within some time window...

Is there an easy way to get a graph of mosfet power dissipation vs time, or, alternately, to compute the dissipation within some time window on the transient analysis? I guess I could do a behavioral voltage source whose output is the product of Id * Vds, and then lowpass filter that. Seems klunky. I'm designing a dumb pure-hysteretic constant-current switcher and applying various st...


Does Fairchild make this MOSFET?

Started by Pimpom in sci.electronics.design7 years ago 7 replies

While browsing the Chinese site www.aliexpress.com, I saw MOSFET FQPF20N60 offered by a number of sellers. It has the Fairchild logo on it but...

While browsing the Chinese site www.aliexpress.com, I saw MOSFET FQPF20N60 offered by a number of sellers. It has the Fairchild logo on it but I can't find any information about it at the Fairchild site or at any of the datasheet sites I use. Neither Digikey nor Mouser nor Farnell/element14 has it either. http://tinyurl.com/ppabzp4 Low-quality semiconductors with popular type numbers p...


Regarding MOSFET.transistor notation/symbol

Started by Anonymous in sci.electronics.design6 years ago 28 replies

Could some electronics guru please clarify the following ? A MOSFET(N/P-MOS) is a symmetrical about the gate, i.e., if in a circuit the drain...

Could some electronics guru please clarify the following ? A MOSFET(N/P-MOS) is a symmetrical about the gate, i.e., if in a circuit the drain and source pins are interchanged, the circuit behavior would not change. So why do textbooks and related literature denote the source node with an arrow ? Same argument holds for a BJT, be it a NPN or a PNP, the device is symmetrical about ...


250 W 2.4 GHz MOSFET...

Started by Jan Panteltje in sci.electronics.design2 years ago 16 replies

250 W 2.4 GHz MOSFET... https://www.ampleon.com/products/rf-energy/2.45-ghz-transistors/BLC2425M9LS250.html Some ham posted he is playing...

250 W 2.4 GHz MOSFET... https://www.ampleon.com/products/rf-energy/2.45-ghz-transistors/BLC2425M9LS250.html Some ham posted he is playing with it to get 250 W up to oscar100... It is actualy quite linear up to 250 W. Seems designed for microwave ovens, Threshold typical 1.75 V 18 dB gain... Interesting thing. 67 $ from digikey Do I see this right and can one make a 24 V microwa...


Negative VG for SiC MOSFETs

Started by Piotr Wyderski in sci.electronics.design3 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


Minimizing destructive HV spikes on square wave push-pull MOSFET drive to transformer

Started by P E Schoen in sci.electronics.design9 years ago 30 replies

I had posted about success with fast MOSFET gate drivers on my 1500 VA = DC-DC=20 converter. The UCC27321 drivers provide up to 9 amps so the...

I had posted about success with fast MOSFET gate drivers on my 1500 VA = DC-DC=20 converter. The UCC27321 drivers provide up to 9 amps so the MOSFETs now=20 switch on and off very quickly compared to the previous drivers, which = were=20 actually gates of an LM324 op-amp. So, although I got better efficiency = and=20 I was able to apply 25 VDC, the 30 volt TVS diodes from each drain to = t...


bjt and mosfet current dependence

Started by Mark Jones in sci.electronics.design9 years ago 4 replies

Anyone know or know where I can find out how the bjt and mosfet parameters = depend on collector and drain currents and voltages? How much will...

Anyone know or know where I can find out how the bjt and mosfet parameters = depend on collector and drain currents and voltages? How much will the effe= ctive resistance of these devices change depending on the current that flow= s through them? Suppose I find a base/gate value at some test conditions that gives me an e= ffective resistance of the device. I'm needing to know how the resist...


Sizing Resistor Wattage for One Short Pulse

Started by Artist in sci.electronics.design6 years ago 70 replies

I am designing an inrush control circuit to prevent a pair of electrolytic bypass capacitors exceeding their rated ripple current when power...

I am designing an inrush control circuit to prevent a pair of electrolytic bypass capacitors exceeding their rated ripple current when power is suddenly applied. When the capacitor is fully charged it will be grounded by a MOSFET. In parallel with the MOSFET there is a current limiting resistor. I do not know what the rise time of the power supply will be. I do know I must protect aga...


What's with the 2sk3018 MOSFET?

Started by Winfield Hill in sci.electronics.design2 years ago 9 replies

The 2sk3018 MOSFET is an unusual animal. It holds the top 30V spot, in my giant MOSFSET table. Its Crss = 4pF at 5V is the lowest, and its...

The 2sk3018 MOSFET is an unusual animal. It holds the top 30V spot, in my giant MOSFSET table. Its Crss = 4pF at 5V is the lowest, and its Ron(max) = 8 ohms, with 4V drive, is the highest, giving it the top spot. It's likely the ideal part for my fast programmable current source. But oops, Rohm says it's NRND. However, it's 2nd sourced by MCC, and Invac and HTsemi. And Ke...


MOSFET WTF

Started by Tim Williams in sci.electronics.design4 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...


Some MOSFET Questions

Started by Anand P. Paralkar in sci.electronics.design7 years ago 2 replies

Hi, I am developing two circuits - a H-bridge inverter and a boost converter, both of which use a MOSFET(s) with a PWM drive and resistive...

Hi, I am developing two circuits - a H-bridge inverter and a boost converter, both of which use a MOSFET(s) with a PWM drive and resistive load. I observe: a. The rise time measured across the drain and source *reduces* as the output load (as in more amps taken at a given output voltage) on these circuits *increases*. b. On the boost converter, for very light loads, the dra...


Positive and negative pulse amplification circuit

Started by captoro in sci.electronics.design9 years ago 11 replies

I have a circuit composed of Lm393 with 12v power supply. I can output two synchronous pulses: +12v and -12v I would like to put a coil between...

I have a circuit composed of Lm393 with 12v power supply. I can output two synchronous pulses: +12v and -12v I would like to put a coil between so I get a 24v difference. Taking the positive side and hooking it up to the coil and a mosfet after the coil. Can I use the -12v as my drain on the mosfet ? I dont want to blow anything up so thats why I am asking what would be best way to do this. ...


op-amp-controlled MOSFET cucrrent-source

Started by Winfield Hill in sci.electronics.design2 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.design13 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.design2 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...


Vertical VHF D-MOSFET used at HF

Started by Clifford Heath in sci.electronics.design5 years ago 5 replies

I have a number of salvaged VHF amplifiers that use the BLF278 dual MOSFET. I was considering re-using some of these transistors in an HF linear...

I have a number of salvaged VHF amplifiers that use the BLF278 dual MOSFET. I was considering re-using some of these transistors in an HF linear amp, say 2-50MHz. The data sheet curves don't go below 50MHz, and the S parameters show that it looks pretty squirrelly below 30MHz - see page 20 of this data sheet (I must say, I don't have a formal understanding of S parameters yet; that's why I'm...