Is a cascode ruled out in your application ?
I ask because both - FETs with high Vds and high input capacitance and FETs with low Vds and low input capacitance are readily available but maybe not the device that you are lookin for.
But maybe you could be a little more specific about the other specs you are looking for (Rdson, PD, Ids, ......).
Regards
Charles
I ask because both - FETs with high Vds and high input capacitance and FETs with low Vds and low input capacitance are readily available but maybe not the device that you are lookin for.
But maybe you could be a little more specific about the other specs you are looking for (Rdson, PD, Ids, ......).
Regards
Charles
Konnichiwa,
Not absolutely, but simplicity dictates to avoid it if possible.
A few Watt Dissipation and < 1A Draincurrent are fine, Rdson is uncritical, as is pretty much anything else. The Voltage and Capacitance parameters are critical. An insulated case would be nice, but is not neccesary.
Sayonara
phase_accurate said:Is a cascode ruled out in your application ?
Not absolutely, but simplicity dictates to avoid it if possible.
phase_accurate said:But maybe you could be a little more specific about the other specs you are looking for (Rdson, PD, Ids, ......).
A few Watt Dissipation and < 1A Draincurrent are fine, Rdson is uncritical, as is pretty much anything else. The Voltage and Capacitance parameters are critical. An insulated case would be nice, but is not neccesary.
Sayonara
Konnichiwa,
Yes, IRF710 is a standby choice, but it really has still too much capacitance, plus it's supposedly discontinued.
I have come across lower capacitance types in Toshiba and SGS Catalogues, but they are not readily available from the usual sources and I don't want to buy 1000pcs.
Sayonara
richie00boy said:IRF710 looks like a good choice, one of the lowest Ciss I have come across, available from RS...
Yes, IRF710 is a standby choice, but it really has still too much capacitance, plus it's supposedly discontinued.
I have come across lower capacitance types in Toshiba and SGS Catalogues, but they are not readily available from the usual sources and I don't want to buy 1000pcs.
Sayonara
Unfortunately the IRF710 seems to be the IR model with the lowest input capacitance in the 400 Volts range. And IR Mosfets are the most widespread ones amongst the average distributors.
So there are obviously only those three choices:
1.) Try to get a source for SGS or Toshiba that sells in low quantities.
2.) Use one of the IRF types and arrange your driver accordingly.
3.) Use a cascode consisting of a IRF71x and a smaller FET (which is still not easily obtained with an Ciss of less than 150 pF).
Regards
Charles
So there are obviously only those three choices:
1.) Try to get a source for SGS or Toshiba that sells in low quantities.
2.) Use one of the IRF types and arrange your driver accordingly.
3.) Use a cascode consisting of a IRF71x and a smaller FET (which is still not easily obtained with an Ciss of less than 150 pF).
Regards
Charles
Zetex second sources Supertex, you can order 450 Vds ZVN0545 and ZVP0545 thru DigiKey - Supertex is carried by some major dist houses, 500 V parts are available
ZVN0545 in sot-223 can be handled like a thru-hole - has ~.1" lead spacing, and metal tab that could be soldered to a Cu flag for 2W P without going the full smt route - a few could be paralleled for some power margin
ZVN0545 in sot-223 can be handled like a thru-hole - has ~.1" lead spacing, and metal tab that could be soldered to a Cu flag for 2W P without going the full smt route - a few could be paralleled for some power margin
STW11NB80? Idunno... works for me, datasheet says "low capacitance"...
An externally hosted image should be here but it was not working when we last tested it.
Konnichiwa,
Arigatou gozaimas to all.
Arigatou, just what the doc ordered. Ciss70pF....
With 2.9nF Ciss I'd rather not, but thanks anyway.
Sayonara
Arigatou gozaimas to all.
jcx said:ZVN0545 in sot-223
Arigatou, just what the doc ordered. Ciss70pF....
Sch3mat1c said:STW11NB80?
With 2.9nF Ciss I'd rather not, but thanks anyway.
Sayonara
If I may highjack this old thread...
Does the IRF710 need a heatsink? If used as an active load for preamp valves. In particular Allen Wrights FVP.
I was looking over the data sheet, but im a bit stuck really. Is there a heat dissipation/heatsink guideline/equation I can use?
Many thanks
Charlie
Does the IRF710 need a heatsink? If used as an active load for preamp valves. In particular Allen Wrights FVP.
I was looking over the data sheet, but im a bit stuck really. Is there a heat dissipation/heatsink guideline/equation I can use?
Many thanks
Charlie
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