| Author |
Message |
Winfield Hill
Guest
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 Posted:
Sat Jan 29, 2005 7:53 am Post subject:
Re: Logic level HV fet... |
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Rich Grise wrote...
| Quote: |
Have Jim Thompson design one for you. ;-)
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Jim's an IC guy (yes, a great one), not a discrete power-device guy.
--
Thanks,
- Win
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Winfield Hill
Guest
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| Posted:
Sat Jan 29, 2005 7:01 pm Post subject:
Re: Logic level HV fet... |
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john jardine wrote...
| Quote: |
Winfield Hill wrote ...
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.
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Not at all.
| 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.
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Are we looking at the same datasheet? I don't see plots of Rds vs Vgs,
and trying to infer Rds(on) at 4 or 5V from the draftsman's version of
the characteristic curves is usually a futile exercise.
| 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. :-).
|
I know they're not common, but PartMiner's parametric search of 200V
mosfets turns up 107 parts that have Rds(on) specified at 5V or lower.
The o.p. may wish to avoid choosing an overly-large FET, to benefit from
lower gate capacitance.
Some logic-level 200V TO-220 n-channel mosfets
mosfet Rds(on) @ Vgs Ciss
-------- ------ --- ------
IRL620A 0.8 5V 330pF
IRLS620A 0.8 5 330 insulated case :>)
FQP7N20L 0.78 5 390
2sk3215 0.55 4 410
IRL630 0.4 5 1100 old part, higher capacitance
IRLi630g 0.4 5 1100 old part, high cap, insulated
IRL630A 0.4 5 580
IRLS630A 0.4 5 580 insulated case :>)
FQE10n20LC 0.39 5 375 insulated case :>)
2sk3214 0.19 4 1100
2sk3160 0.19 4 1100 insulated case :>)
IRLi640g 0.18 5 1800 old part, high cap, insulated
IRL640A 0.18 5 1310
IRLS640A 0.18 5 1310 insulated case :>)
FQP19n20L 0.15 5 1700
FQP34n20L 0.08 5 3000
FQPF34n20L 0.08 5 3000 insulated case :>)
In this instance, there's little reason to use parts specified at 10V
and guess their properties at 5V or less. BTW, when someone tells me
they're using a 9V supply, I assume a 9V battery, which means 5 or 6V
is more reasonable minimum operating voltage.
--
Thanks,
- Win |
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Winfield Hill
Guest
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| Posted:
Sat Jan 29, 2005 8:07 pm Post subject:
Re: Logic level HV fet... |
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Winfield Hill wrote...
| Quote: |
Some logic-level 200V TO-220 n-channel mosfets
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With a few more added...
mosfet Rds(on) @ Vgs Ciss comments
-------- ------ --- ------ ---------------
IRL620A 0.8 5V 330pF
IRLS620A 0.8 5 330 insulated case
FQP7N20L 0.78 5 390
2sk3215 0.55 4 410
IRL630 0.4 5 1100 old part, higher capacitance
IRLi630g 0.4 5 1100 old part, high cap, insulated
IRL630A 0.4 5 580
IRLS630A 0.4 5 580 insulated case
FQE10n20LC 0.39 5 375 nice low-cap, TO-126, insulated
fqp10n20L 0.38 5 640 fqd10n20L easier to get
2sk3214 0.19 4 1100
2sk3160 0.19 4 1100 insulated case
IRLi640g 0.18 5 1800 old part, high cap, insulated
IRL640A 0.18 5 1310
IRLS640A 0.18 5 1310 insulated case
FQP19n20L 0.15 5 1700
FQPF19n20L 0.15 5 1700 insulated case
FQP34n20L 0.08 5 3000
FQPF34n20L 0.08 5 3000 insulated case
Fairchild's amazing low-gate-charge FQE10n20LC seems hard to find.
But the rest of the Fairchild '10n20L series is still attractive.
Mouser stocks most of the SMT parts in the line, for example the
FQD10n20L costs $0.63 qty 100.
BTW, considering newer-style packages dramatically increases the
number of logic-level FET choices available.
--
Thanks,
- Win
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Watson A.Name - \"Watt Su
Guest
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| Posted:
Sat Jan 29, 2005 10:17 pm Post subject:
Re: Logic level HV fet... |
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"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:YwyKd.17555$wZ2.12343@newssvr13.news.prodigy.com...
| Quote: | Hello John,
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.
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.
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Somehow I see the contrast between high tech electronics and heating
with a wood stove as just too great. :-)
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Watson A.Name - \"Watt Su
Guest
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| Posted:
Sat Jan 29, 2005 10:24 pm Post subject:
Re: Logic level HV fet... |
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"Winfield Hill" <hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote in
message news:ctg1fp014d4@drn.newsguy.com...
[snip]
| Quote: | BTW, when someone tells me
they're using a 9V supply, I assume a 9V battery, which means 5 or 6V
is more reasonable minimum operating voltage.
|
If one goes by the single cell figures, one could run all 6 cells down
to 1V per cell or 6V total, but for some apps that use a regulator (not
LDO), 7.5V seems to be the minimum.
But then I regularly let some CMOS circuits run 'em down to 3V. :o)
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keith
Guest
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| Posted:
Sat Jan 29, 2005 11:17 pm Post subject:
Re: Logic level HV fet... |
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On Fri, 28 Jan 2005 17:53:04 -0800, Winfield Hill wrote:
| Quote: | Rich Grise wrote...
Have Jim Thompson design one for you. ;-)
Jim's an IC guy (yes, a great one), not a discrete power-device guy.
|
Storytime. Once upon a time many moons ago we had a contactor-driver that
was making a mess of customer's offices. It seems it was breaking down on
the turn-off cycle and letting the magic smoke out of a few $M of hardware
every so often (bad for executives' ulcers). After researching the
problem it was found that only one manufacturer of the part had the
problem[*]. It was a logic IC manufacturer (one that I think Jim may have
worked for;-). The power device manufacturer's part never failed. I
couldn't force it into the failure mode (secondary breakdown) without it
avalanching first. It seems manufacturer 'A' had IC designers design a
power device, while manufacturer 'B' had power device designers design an
IC. Power devices aren't just biger transistors.
[*] To be fair, the design of the circuit was at fault. Had it been right
both parts would have worked fine, but one device was far more robust than
the other.
--
Keith |
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Fritz Schlunder
Guest
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| Posted:
Sat Jan 29, 2005 11:32 pm Post subject:
Re: Logic level HV fet... |
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"Winfield Hill" <hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote in
message news:ctdatk01mre@drn.newsguy.com...
| Quote: | 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.
|
Blaa... Blaaa... Blasphemy! That is blasphemy to my ears friend.
There are a number of features that make the Si4490DY interesting. That
part is a trench MOSFET. That by itself is interesting to me, I wasn't
aware anyone was making medium voltage trench MOSFETs. Upon looking at
Vishay's MOSFET lineup I now see they have quite a selection of modest
voltage trench products up to 250V.
The MOSFET has very impressively low 80milliOhm on resistance for a 200V
part in a SO8 package. That alone is pretty special. That might be an
industry record by itself. The part also has substantially lower gate
charge than might be expected at only 42nC at 10V. That is very good
considering that something like the IRF640N has 67nC gate charge but a much
higher 0.15 Ohm on resistance. The Si4490DY also features an extremely good
body diode reverse recovery time rating (70ns typical, 100ns max.).
Unfortunately the datasheet is really skimpy and missing allot of details
(such as diode reverse recovery charge), but for a 200V rated part this is
clearly superior to pretty much all of its competition. Mouser sells them
for $1.95 in single unit quantity. That isn't anything too special to write
home about, but at least it is available if your application calls for it.
Although trench MOSFETs usually have inferior avalanche ruggedness compared
to their planar counterparts, the Si4490DY is still avalanche rated and is
still fairly robust in that category as well. The on resistance versus
temperature graph may also be ever so slightly superior to many of it's
potential competitors.
Overall it is certainly noteworthy, even if it only makes evolutionary
improvements on other previous and current parts. |
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Jim Thompson
Guest
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| Posted:
Sat Jan 29, 2005 11:32 pm Post subject:
Re: Logic level HV fet... |
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On Sat, 29 Jan 2005 12:17:51 -0500, keith <krw@att.bizzzz> wrote:
| Quote: | On Fri, 28 Jan 2005 17:53:04 -0800, Winfield Hill wrote:
Rich Grise wrote...
Have Jim Thompson design one for you. ;-)
Jim's an IC guy (yes, a great one), not a discrete power-device guy.
Storytime. Once upon a time many moons ago we had a contactor-driver that
was making a mess of customer's offices. It seems it was breaking down on
the turn-off cycle and letting the magic smoke out of a few $M of hardware
every so often (bad for executives' ulcers). After researching the
problem it was found that only one manufacturer of the part had the
problem[*]. It was a logic IC manufacturer (one that I think Jim may have
worked for;-). The power device manufacturer's part never failed. I
couldn't force it into the failure mode (secondary breakdown) without it
avalanching first. It seems manufacturer 'A' had IC designers design a
power device, while manufacturer 'B' had power device designers design an
IC. Power devices aren't just biger transistors.
[*] To be fair, the design of the circuit was at fault. Had it been right
both parts would have worked fine, but one device was far more robust than
the other.
|
Circuit designers don't design power semiconductors. It's usually
done by artists who specialize in such things. Usually they don't
have a clue about real circuits until a customer complains, or
failures are high.
I worked for Motorola Semiconductor in the '60's and have consulted to
various Motorola and ON Semiconductor divisions since then.
I haven't done any hardware design using off-the-shelf components
since 1987, though I now am often retained to design an I/C which must
interface to discrete power devices.
And I've designed many an off-line switcher BEFORE there were
application-specific I/Cs available for the task.
And I put the first hex-FET into space... fixing the Shuttle power
supply redundancy problem that guaranteed domino-style power supply
failure ;-)
...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. |
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keith
Guest
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| Posted:
Sun Jan 30, 2005 12:33 am Post subject:
Re: Logic level HV fet... |
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On Sat, 29 Jan 2005 10:32:47 -0700, Jim Thompson wrote:
| Quote: | On Sat, 29 Jan 2005 12:17:51 -0500, keith <krw@att.bizzzz> wrote:
On Fri, 28 Jan 2005 17:53:04 -0800, Winfield Hill wrote:
Rich Grise wrote...
Have Jim Thompson design one for you. ;-)
Jim's an IC guy (yes, a great one), not a discrete power-device guy.
Storytime. Once upon a time many moons ago we had a contactor-driver that
was making a mess of customer's offices. It seems it was breaking down on
the turn-off cycle and letting the magic smoke out of a few $M of hardware
every so often (bad for executives' ulcers). After researching the
problem it was found that only one manufacturer of the part had the
problem[*]. It was a logic IC manufacturer (one that I think Jim may have
worked for;-). The power device manufacturer's part never failed. I
couldn't force it into the failure mode (secondary breakdown) without it
avalanching first. It seems manufacturer 'A' had IC designers design a
power device, while manufacturer 'B' had power device designers design an
IC. Power devices aren't just biger transistors.
[*] To be fair, the design of the circuit was at fault. Had it been right
both parts would have worked fine, but one device was far more robust than
the other.
Circuit designers don't design power semiconductors. It's usually
done by artists who specialize in such things. Usually they don't
have a clue about real circuits until a customer complains, or
failures are high.
|
Oh, they got complaints, alright. Right to the top! Mano a Mano,
CEO a CEO, as it were.
| Quote: | I worked for Motorola Semiconductor in the '60's and have consulted to
various Motorola and ON Semiconductor divisions since then.
|
Missed by a decade. ;-)
| Quote: | I haven't done any hardware design using off-the-shelf components
since 1987, though I now am often retained to design an I/C which must
interface to discrete power devices.
And I've designed many an off-line switcher BEFORE there were
application-specific I/Cs available for the task.
And I put the first hex-FET into space... fixing the Shuttle power
supply redundancy problem that guaranteed domino-style power supply
failure ;-)
|
--
Keith |
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legg
Guest
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| Posted:
Sun Jan 30, 2005 12:47 am Post subject:
Re: Logic level HV fet... |
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On Sat, 29 Jan 2005 10:32:32 -0700, "Fritz Schlunder" <me@privacy.net>
wrote:
| Quote: | 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.
Overall it is certainly noteworthy, even if it only makes evolutionary
improvements on other previous and current parts.
It ain't watcha got, its the way hatcha do it. |
RL |
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Joerg
Guest
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| Posted:
Sun Jan 30, 2005 8:33 am Post subject:
Re: Logic level HV fet... |
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Hi Watson,
| Quote: | 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.
Somehow I see the contrast between high tech electronics and heating
with a wood stove as just too great. :-)
|
Not really. Newer wood stoves are pretty nifty devices, blue flames, no
smoke. No stuffed nose from forced-air heating. Lots of exercise without
gym membership fees. But best of all, when the wood stove runs the
exorbitant cost from propane usage drops to zilch. It's pretty power
outage proof, too.
Cooking out here is sometimes equally rustic. Right now a turkey is
slowly getting ready in the Weber charcoal grill. With mesquite chips,
marinade injection and the whole nine yards. We always make sure to have
at least 100 pounds of charcoal before the winter begins and stores run
out. If that ain't enough, guess what, we scavenge some from the wood
stove. Talking about multi-tasking... ;-)
Regards, Joerg
http://www.analogconsultants.com |
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