Amazon

Why can't you order from Digikey without a PO? I do often.

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Rick

We used to check for sealing by placing the sealed part into water just below boiling temperature. If it leaks, air bubbles emerge.

Is that within the parameters of the device?

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Rick

We bought some cheap parts from Jameco.. years ago. (never again, my time etc...)

For one-of's its OK.

George H.

The idea is to dunk them in water in a bell jar (also from Amazon) and pull a vac and see if they bubble. Then return to atmospheric and see if any water is forced inside; we can check for resistance.

These relays are supposed to be sealed, and every one tested, but we are getting water inside some, after pick+place and water wash. We are temporarily back to rosin flux and solvent wash, but we want to understand it.

Jameco sold floor sweepings, not too much different from what RadioShaft sold by the bag.

For hobbies, perhaps. Time us worth too much to futz around with junk parts.

I may have misspoke on the temperature. It was a military power supply and we followed their requirements. I vaguely remember a hotplate, pot of water and a thermometer.

I don't trust them full stop. When buying from China there's no effective law governing the product or business, and rejections/refunds are a complete gamble. Some buys yield duds.

When you can work with that the savings are attractive. Here we have to watch for products that work but aren't legal for work use or sale.

If the chocolate fails to stay sealed under pressure I could check it for you. Some of the tests might be destructive.

NT

Yup, I bought some "Xilinx" 9500 CPLDs, and it is awfully clear they are counterfeits. They don't have a pin 1 keying dot, and the date code seems to indicate they were made after Xilinx stopped making that part. Also, I'm guessing they were untested die, so a few of them don't work. Ugh, have to redesign the board, AGAIN!

Jon

From a non-mainstream disti? I'm a bit worried about that sort of thing. My board uses a part out of production and we managed to find parts a year later when none were around just after the deadline. Somehow Arrow had them available in a large quantity. They may have speculated and ordered a bunch ahead. I'm thinking of buying a few, but I'd like to be sure they are the real deal.

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Rick

The dark chocolate triangular Toblerone bars are often hard to find locally, so I buy them 20 at a time from Amazon. Ditto the Ritter Sport hazelnut things.

I'll consider your testing offer.

From China, via Ali Baba!!!! But, Xilinx discontinued the part, and I wasn't savvy enough to buy all I'd need before they became unobtanium.

Well, now Digi-Key and Avnet are the only licensed Xilinx distributors. But, I'd suspect Arrow would not be selling counterfeit schlock knowingly, but you never know how these things get into the supply chain. As soon as I use up these boards, I will respin to use available parts.

Jon

I would like to respin the board I make, but I used a 100QFP which no other decent FPGA comes in. I'd have to go BGA which I am not inclined to do. It would provide for a *lot* more circuitry, but I don't think the customer has any need for that. I just want to keep costs down.

I just built over 600 of these things and I got a pretty good price on the first 500+. Then the customer sent me another PO for over 100 more and the price to me jumped up some $40. I think the price of the FPGA jumped up quite a bit. The $10 part was going for $40+ when I searched for them while they had been close to $10 the month before when I placed the first order. Such is business. If I didn't have a large markup I would be raising my prices.

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Rick

On Wednesday, 30 September 2015 20:35:22 UTC+1, John Larkin wrote: nt:

Fruit chocolate often suffers from currant leakage.

NT

Sometimes you feel like a nut.

YEAH!! I hear you, I'm in the same dilemma. Xilinx is still making the Spartan 3A (and AN) in 144-pin QFP (and maybe in the 100, too), but these are the smallest end of that product line, the 50-size. I am comfortable with the QFPs, but really don't want to learn the ins and outs of BGAs.

Yup, the vultures will charge an arm and a leg for parts that used to be quite cheap. I did buy just a couple 5V Spartan parts for a very old legacy board that I make a couple a year or. They were $60 or so each.

Jon

make sense that the price goes up so only those who really need them get the stock that is left and not someone starting a new product with an obsolete part

-Lasse

When the current part was announced to become EOL I did a survey and there are only a few 100 QFP parts made other than devices with less capability. The Spartan parts are of the same age as the Lattice EOL parts and the Altera parts are even older. Maybe I wouldn't have to worry about these parts going EOL for another 10 years, but it would still be a respin of the board and they require a separate flash chip for configuration. So if a respin is done, I would use a newer device and get more functionality and perhaps a lower cost.

The problem with BGAs is not so much any "ins and outs" or gotchas really. It is board space. The QFP let me route directly from the pins so the area under and around the QFP have only the vias that are needed there. A BGA has little access to most of the pins other than with vias. Depending on the pitch this can drive up the cost of the board and use more real estate making the board harder to route. The one end of the board is already a B***H to route and I don't need more headaches with the FPGA area. Plopping down a 100QFP with different power and grounds will cause enough trouble without having to find new locations for parts on the other side of the board from the FPGA.

You call them vultures, but it is just supply and demand. These parts were EOL'd over a year ago and I am happy to find *any* parts at all on the market. I could have ordered any parts I wanted for delivery up to

3 years after EOL. But I'm not in the IC speculation market. Maybe I should be, lol!

Anyone need 5 volt flash parts? I've got some.

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Rick

junk parts?