| Author |
Message |
legg
Guest
|
 Posted:
Fri Jan 28, 2005 12:01 pm Post subject:
Re: Logic level HV fet... |
|
|
On Thu, 27 Jan 2005 21:01:24 -0700, "Fritz Schlunder" <me@privacy.net>
wrote:
| Quote: |
"legg" <legg@nospam.magma.ca> wrote in message
news:944jv0h42j87qd6rejrfqa7lm2qqoeb0iv@4ax.com...
On Thu, 27 Jan 2005 10:29:28 -0000, "Mike Deblis"
mdeblis@hotmail.com> wrote:
Hi,
I'm looking for a 200 - 250V FET with low Qg, low RDSon (only needs maybe
3A
peak Ids, but low RDSon for efficiency) and LOGIC LEVEL GATE for use in
an
SMPS that only has a 9V supply - the SMPS is in boost configuration to
give
180V @ 20mA out, probably going to use the LTC1872 if I can.
Any ideas would be appreciated - I've not had a lot of luck so far - I
know
its a tall order. An SMD footprint would also be good.
Siliconix Si4490DY Nchannel 200V 0R09 in SO8, is characterized with
6Vds.
http://www.vishay.com/doc?71341
RL
Hey now that is an interesting part. I wonder how much it costs...
|
The last time I was fooling with 150V parts, top of the line SO8
packages were about US$ 1.70, when they hit their intended volume.
Small quantities and early parts could be three times that.
Never inquired about Si4490. The 150V parts were 0R05 or less.
RL
|
|
| Back to top |
|
 |
Genome
Guest
|
| Posted:
Fri Jan 28, 2005 1:41 pm Post subject:
Re: Logic level HV fet... |
|
|
"mike" <spamme0@netscape.net> wrote in message
news:41F99A4F.2090500@netscape.net...
| Quote: | Genome wrote:
"Mike Deblis" <mdeblis@hotmail.com> wrote in message
news:35ru47F4mkh6eU1@individual.net...
Hi,
I'm looking for a 200 - 250V FET with low Qg, low RDSon (only needs
maybe
3A
peak Ids, but low RDSon for efficiency) and LOGIC LEVEL GATE for use in
an
SMPS that only has a 9V supply - the SMPS is in boost configuration to
give
180V @ 20mA out, probably going to use the LTC1872 if I can.
Any ideas would be appreciated - I've not had a lot of luck so far - I
know
its a tall order. An SMD footprint would also be good.
Thanks
Mike
Use a voltage boosted boost converter. You tap the inductor so that the
FET
sees a fraction of the output voltage.
----nnnnnnnnnnnn----->|-----
|
|
|--
|<-
|--
|
|
-------------------------------
DNA
Once you've decided to tap the inductor, is there any practical
difference between that and a transformer.
|
A) With one bit of wire. Start pin A wind 10, tap pin B wind 90 finish pin
C.
One wire, three terminations. One setup.
{5}
B) With one bit of wire. Start pin A wind 10, terminate pin B.
With next bit of wire. Start pin C wind 90 finish pin D.
Two wires, four terminations. Two setups.
{8}
| Quote: | Probably still want different size wire in the two sections anyway.
mike
|
If you want to be a purist..... but..... does the cost function work in your
favour? Materials/Labour/Error.
Is it your Mother or some Chinese bit of shit doing the winding for you?
I know we've just celebrated fucking off 6 million and a bit Jews, and the
idiots still let Woody Allens parents get away!!!!!, but your Mum versus an
odd Billion Chinkies could be a powerful persuader.
DNA |
|
| Back to top |
|
|
mike
Guest
|
| Posted:
Fri Jan 28, 2005 3:21 pm Post subject:
Re: Logic level HV fet... |
|
|
Genome wrote:
snipped all the bigoted stuff
Why'd you have to go ruin a perfectly good suggestion with all that
crap.
Of course, you have to do the math for all the options. But you can at
least be objective about it.
mike
--
Return address is VALID.
Wanted, PCMCIA SCSI Card for HP m820 CDRW.
FS 500MHz Tek DSOscilloscope TDS540 Make Offer
http://nm7u.tripod.com/homepage/te.html
Wanted, 12.1" LCD for Gateway Solo 5300. Samsung LT121SU-121
Bunch of stuff For Sale and Wanted at the link below.
http://www.geocities.com/SiliconValley/Monitor/4710/
|
|
| Back to top |
|
|
Winfield Hill
Guest
|
| Posted:
Fri Jan 28, 2005 6:24 pm Post subject:
Re: Logic level HV fet... |
|
|
legg wrote...
| Quote: |
Fritz Schlunder wrote:
legg wrote...
Mike Deblis wrote:
I'm looking for a 200 - 250V FET with low Qg, low RDSon (only needs
maybe 3A peak Ids, but low RDSon for efficiency) and LOGIC LEVEL
GATE for use in an SMPS that only has a 9V supply ...
Siliconix Si4490DY Nchannel 200V 0R09 in SO8, is characterized with
6Vds. http://www.vishay.com/doc?71341
Hey now that is an interesting part. I wonder how much it costs...
Never inquired about Si4490. The 150V parts were 0R05 or less.
|
It's a boring part. Yawn.
--
Thanks,
- Win |
|
| Back to top |
|
|
Winfield Hill
Guest
|
| Posted:
Fri Jan 28, 2005 6:28 pm Post subject:
Re: Logic level HV fet... |
|
|
john jardine wrote...
| Quote: |
Mike Deblis wrote:
I'm looking for a 200 - 250V FET with low Qg, low RDSon (only
needs maybe 3A peak Ids, but low RDSon for efficiency) and
LOGIC LEVEL GATE for use in an SMPS that only has a 9V supply ...
The 2SK2350 is 200V, 0.26ohms, with 4V gate drive.
|
It appears the 0.26ohm rating is with 10V drive.
That's a boring part. Nothing special. Yawn.
--
Thanks,
- Win |
|
| Back to top |
|
|
john jardine
Guest
|
| Posted:
Fri Jan 28, 2005 10:59 pm Post subject:
Re: Logic level HV fet... |
|
|
"Winfield Hill" <hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote in
message news:ctdb4j01nfl@drn.newsguy.com...
| Quote: | john jardine wrote...
Mike Deblis wrote:
I'm looking for a 200 - 250V FET with low Qg, low RDSon (only
needs maybe 3A peak Ids, but low RDSon for efficiency) and
LOGIC LEVEL GATE for use in an SMPS that only has a 9V supply ...
The 2SK2350 is 200V, 0.26ohms, with 4V gate drive.
It appears the 0.26ohm rating is with 10V drive.
That's a boring part. Nothing special. Yawn.
--
Thanks,
- Win
|
Yes but only on a casual reading.
Look at the graphs. This fet has very nearly the same Ron at a 5V gate. This
is in sharp contrast to many Fets advertised as being 'logic-level' when in
actual fact they are barely starting to move, hence incapable of doing any
real work at this drive level.
Go on then, suggest a logic level fet, easily available at a reasonable
price, that should be preferred for this switching job. An insulated case
type would be nice. :-).
regards
john |
|
| Back to top |
|
|
legg
Guest
|
| Posted:
Sat Jan 29, 2005 12:25 am Post subject:
Re: Logic level HV fet... |
|
|
On 28 Jan 2005 04:24:20 -0800, Winfield Hill
<hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:
| Quote: | legg wrote...
Fritz Schlunder wrote:
legg wrote...
Mike Deblis wrote:
I'm looking for a 200 - 250V FET with low Qg, low RDSon (only needs
maybe 3A peak Ids, but low RDSon for efficiency) and LOGIC LEVEL
GATE for use in an SMPS that only has a 9V supply ...
Siliconix Si4490DY Nchannel 200V 0R09 in SO8, is characterized with
6Vds. http://www.vishay.com/doc?71341
Hey now that is an interesting part. I wonder how much it costs...
Never inquired about Si4490. The 150V parts were 0R05 or less.
It's a boring part. Yawn.
|
Reality is such a bore!
Shall I peel you a grape?
RL |
|
| Back to top |
|
|
Rich Grise
Guest
|
| Posted:
Sat Jan 29, 2005 2:30 am Post subject:
Re: Logic level HV fet... |
|
|
On Fri, 28 Jan 2005 01:21:27 -0800, mike wrote:
| Quote: | Genome wrote:
snipped all the bigoted stuff
Why'd you have to go ruin a perfectly good suggestion with all that
crap.
Of course, you have to do the math for all the options. But you can at
least be objective about it.
Oh, I've plonked Genome some time ago for gratuitous vulgarity. |
Thanks for the reminder!
Rich |
|
| Back to top |
|
|
Rich Grise
Guest
|
| Posted:
Sat Jan 29, 2005 3:18 am Post subject:
Re: Logic level HV fet... |
|
|
On Fri, 28 Jan 2005 16:59:48 +0000, john jardine wrote:
| Quote: | "Winfield Hill" <hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote in
john jardine wrote...
Mike Deblis wrote:
I'm looking for a 200 - 250V FET with low Qg, low RDSon (only
needs maybe 3A peak Ids, but low RDSon for efficiency) and
LOGIC LEVEL GATE for use in an SMPS that only has a 9V supply ...
The 2SK2350 is 200V, 0.26ohms, with 4V gate drive.
It appears the 0.26ohm rating is with 10V drive.
That's a boring part. Nothing special. Yawn.
Yes but only on a casual reading.
Look at the graphs. This fet has very nearly the same Ron at a 5V gate. This
is in sharp contrast to many Fets advertised as being 'logic-level' when in
actual fact they are barely starting to move, hence incapable of doing any
real work at this drive level.
Go on then, suggest a logic level fet, easily available at a reasonable
price, that should be preferred for this switching job. An insulated case
type would be nice. :-).
|
Have Jim Thompson design one for you. ;-)
Cheers!
Rich |
|
| Back to top |
|
|
Rich Grise
Guest
|
| Posted:
Sat Jan 29, 2005 3:20 am Post subject:
Re: Logic level HV fet... |
|
|
On Fri, 28 Jan 2005 18:25:47 +0000, legg wrote:
| Quote: | On 28 Jan 2005 04:24:20 -0800, Winfield Hill
hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:
legg wrote...
Fritz Schlunder wrote:
legg wrote...
Mike Deblis wrote:
I'm looking for a 200 - 250V FET with low Qg, low RDSon (only needs
maybe 3A peak Ids, but low RDSon for efficiency) and LOGIC LEVEL
GATE for use in an SMPS that only has a 9V supply ...
Siliconix Si4490DY Nchannel 200V 0R09 in SO8, is characterized with
6Vds. http://www.vishay.com/doc?71341
Hey now that is an interesting part. I wonder how much it costs...
Never inquired about Si4490. The 150V parts were 0R05 or less.
It's a boring part. Yawn.
Reality is such a bore!
Shall I peel you a grape?
Silly me! I thought he was talking about his role. ;-) |
Cheers!
Rich |
|
| Back to top |
|
|
Joerg
Guest
|
| Posted:
Sat Jan 29, 2005 3:55 am Post subject:
Re: Logic level HV fet... |
|
|
Hello John,
| Quote: | Look at the graphs. This fet has very nearly the same Ron at a 5V gate. This
is in sharp contrast to many Fets advertised as being 'logic-level' when in
actual fact they are barely starting to move, hence incapable of doing any
real work at this drive level.
|
If you look at the Vgs versus Vds graph in the middle of page 3 there is
less than a volt of head room at 5V gate drive before Vds shoots up and
potentially turns the device into a pile of ash. Too close for comfort
to me.
| Quote: | Go on then, suggest a logic level fet, easily available at a reasonable
price, that should be preferred for this switching job. An insulated case
type would be nice. :-).
|
That's just the problem, not much out there. It is an issue I run into a
lot and often end up with bipolar transistors. What really drives me up
the wall is a glitzy ad for some new FET, saying it is guaranteed 3V or
something and then in the fine print I find that was for 1mA and Vds=1V.
At least one can then crumple the data sheet, form a ball and smack it
into the bin across the room. Or use it to light the wood stove.
Regards, Joerg
http://www.analogconsultants.com |
|
| Back to top |
|
|
Genome
Guest
|
| Posted:
Sat Jan 29, 2005 4:25 am Post subject:
Re: Logic level HV fet... |
|
|
"mike" <spamme0@netscape.net> wrote in message
news:41FA0417.1010100@netscape.net...
| Quote: | Genome wrote:
snipped all the bigoted stuff
Why'd you have to go ruin a perfectly good suggestion with all that
crap.
Of course, you have to do the math for all the options. But you can at
least be objective about it.
mike
--
|
OK, objectively speaking, Mel Brooks might have been worth it.
DNA |
|
| Back to top |
|
|
Genome
Guest
|
| Posted:
Sat Jan 29, 2005 7:19 am Post subject:
Re: Logic level HV fet... |
|
|
"Rich Grise" <richgrise@example.net> wrote in message
news:pan.2005.01.28.20.35.55.45022@example.net...
| Quote: | On Fri, 28 Jan 2005 01:21:27 -0800, mike wrote:
Genome wrote:
snipped all the bigoted stuff
Why'd you have to go ruin a perfectly good suggestion with all that
crap.
Of course, you have to do the math for all the options. But you can at
least be objective about it.
Oh, I've plonked Genome some time ago for gratuitous vulgarity.
Thanks for the reminder!
Rich
|
Ta muchly for plonking me.
Your services are much apprecieated.
DNA |
|
| Back to top |
|
|
Jim Thompson
Guest
|
| Posted:
Sat Jan 29, 2005 7:26 am Post subject:
Re: Logic level HV fet... |
|
|
On Sat, 29 Jan 2005 01:19:07 GMT, "Genome" <ilike_spam@yahoo.co.uk>
wrote:
| Quote: |
"Rich Grise" <richgrise@example.net> wrote in message
news:pan.2005.01.28.20.35.55.45022@example.net...
[snip]
Oh, I've plonked Genome some time ago for gratuitous vulgarity.
Thanks for the reminder!
Rich
Ta muchly for plonking me.
Your services are much apprecieated.
DNA
|
ROTFLMAO!
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
I love to cook with wine. Sometimes I even put it in the food. |
|
| Back to top |
|
|
Winfield Hill
Guest
|
| Posted:
Sat Jan 29, 2005 7:51 am Post subject:
Re: Logic level HV fet... |
|
|
legg wrote...
| Quote: |
Shall I peel you a grape?
|
No, I prefer it with the skin.
--
Thanks,
- Win |
|
| Back to top |
|
|
|
|
|
|
FAQ
Memberlist
Register
Profile
Log in to check your private messages
Log in