Logic level HV fet...

[Winfield Hill]

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.


--
Thanks,
- Win

 

[Winfield Hill]

john jardine wrote...

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.

Not at all.

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.

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.

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 :&gt
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 :&gt
FQE10n20LC 0.39 5 375 insulated case :&gt
2sk3214 0.19 4 1100
2sk3160 0.19 4 1100 insulated case :&gt
IRLi640g 0.18 5 1800 old part, high cap, insulated
IRL640A 0.18 5 1310
IRLS640A 0.18 5 1310 insulated case :&gt
FQP19n20L 0.15 5 1700
FQP34n20L 0.08 5 3000
FQPF34n20L 0.08 5 3000 insulated case :&gt

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

 

[Winfield Hill]

Winfield Hill wrote...

Some logic-level 200V TO-220 n-channel mosfets

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

 

[Watson A.Name - \"Watt Su]

"Winfield Hill" <hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote in
message news:ctg1fp014d4@drn.newsguy.com...

[snip]

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. )

--
Thanks,
- Win

 

[keith]

On Sat, 29 Jan 2005 10:32:47 -0700, Jim Thompson wrote:

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.

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. ;-)

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

 

[legg]

On Sat, 29 Jan 2005 10:32:32 -0700, "Fritz Schlunder" <me@privacy.net>
wrote:

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

 

[mike]

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. Probably still want
different size wire in the two sections anyway.
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/

 

[legg]

On Thu, 27 Jan 2005 21:01:24 -0700, "Fritz Schlunder" <me@privacy.net>
wrote:

"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