Logic level HV fet...

Oh, I've plonked Genome some time ago for gratuitous vulgarity.

Thanks for the reminder! Rich

Have Jim Thompson design one for you. ;-)

Cheers! Rich

Silly me! I thought he was talking about his role. ;-)

Cheers! Rich

Hello John,

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.

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

OK, objectively speaking, Mel Brooks might have been worth it.

DNA

Ta muchly for plonking me.

Your services are much apprecieated.

DNA

[snip]

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 | |

| 1962 | I love to cook with wine. Sometimes I even put it in the food.

No, I prefer it with the skin.

--
 Thanks,
    - Win

Jim's an IC guy (yes, a great one), not a discrete power-device guy.

--
 Thanks,
    - Win

Not at all.

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.

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

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

gate. This

when in

doing any

is

and

reasonable

case

a

up

or

Vds=1V.

Somehow I see the contrast between high tech electronics and heating with a wood stove as just too great. :-)

[snip]

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)

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

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.

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.

Oh, they got complaints, alright. Right to the top! Mano a Mano, CEO a CEO, as it were.

Missed by a decade. ;-)

--
  Keith

It ain't watcha got, its the way hatcha do it.

RL

Hi Watson,

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