grrrrr

Ok, yes, some of the more rare species can't be found at Digikey. Lots of my RF parts that I need in designs aren't either, such as power inductors or ferrite cores. And when the handle on a hose bib broke Digikey didn't have one. Unbelievable ... :-)

But seriously, the fact that even Farnell stocks only 69 of the 74VHC161 right now and the fact that major distributors list 12-13 weeks lead time versus 4-6 weeks for a 74HC161 would make me think twice about using it in a design. Now I don't know about this one because I rarely use such stuff but sometimes those are the first clouds on the horizon.

Panasonic has had a massive paring of the items they produce. The MA2J11100 is no longer made, and some PQ LDO regulator chips are also discontinued. These were the smallest 100 mA LDOs and were PERFECT for powering one Xilinx FPGA. Being burned on that one, and just barely having enough to finish existing PC boards, I went with the ZLDO1117 series of LDOs, which are widely available but at least 4 times the PCB area.

I just prototyped an ECO to a board with a rather odd depletion-mode NFET, which worked GREAT to reduce the dropout voltage of a DAC-adjustable regulator circuit. When proved to work, I went back to get more, and they are unavailable from ANY franchised supplier WORLDWIDE! I had to scrounge some parts on the secondary market, and I always worry about recycled or counterfeit parts there. (Been burned that way, too!)

Jon

I've been using MicroChip TC1016s for point-of-use regulators for situations like that. They work great and I've gotten quite fond of the SC-70 package. ;-)

If there is a situation where space is of prime concern and quantities are huge it can pay off to talk this over with a few IC design houses. They have products that aren't listed anywhere at distributors. In quantities it isn't terribly expensive (BTDT).

The only N-channel depletion mode FETs I'd rely on to be availiable in quantities would be the ones from Clare. And only if I really, really have to. CPC5602, for example.

You wouldn't trust Supertex?

I like the Supertex parts. They have 500 volt SOT23 depletion fets, which are great for input protection circuits. This will stand 300 volt overloads on the millivolts-input ranges.

ftp://jjlarkin.lmi.net/22S490B_ch12.pdf

That CPC5602 Clare datasheet is sort of pitiful.

Doesn't somebody else, a european company maybe, make depletion fets?

John

I didn't run across any in my search (couple of years ago) when I found Supertex for my depletion need. Doesn't mean they aren't there, of course.

John S

Aha! How about...

watch the wrap. Sorry about that.

Oh, I do. It's a great company and Ken and the guys are always responsive. But I usually need bigger than SOT23. And FETs like the the DN2450 or DN3765 are zero stock at Arrow, Digikey doesn't carry them at all, that's something my clients often don't like. They want serious availability at mainstream distributors.

On the Clare part Digikey has thousands, Arrow has thousands.

Mouser carries Supertex and they have stock in TO-92, D-Pak, TO-220, etc. Of course, I haven't read your electrical requirements, so maybe they still will not fit.

Sure, but have you checked distributor stock lately? For example, for the IXTY02 Digikey has 75, Mouser has 75. Arrow ... nada, zip, zilch.

Though I can't wait until their 4kV FET becomes available. That ought to be the mother of all FETs.

Well, I don't remember that you said you needed more than 150 of them. My mistake, if you did.

Maybe they will be more available than the one you want now (err.. how do you make that smiley symbol?)

Does it appear that's by intent, or could it be just incompetence?

Drop them a line.

Sylvia.

I usually design for production and then they'll need then by the reels, for the SMT automatic placement machines.

Like this: : - )

Just leave out the two spaces inbetween. When you put those three characters right next to each other most modern email software will turn it into a smiley.

Couldn't find much there in depletion mode but then again the Mouser search engine doesn't work well. Never has. Which is why a manufacturer should strive to have stock at Digikey, it's the only place with a well-oiled search engine.

Yikes, 20 amp Idss depletion fets. They must be good for something fun.

John

As my old mentor Melvin Goldstein used to say, "The easiest thing is the world is not to sell."

John

I reckon "normally closed" solid state relays?