Helping with TI's XTR117 ??? (SON8 DFN package)

Interesting. It is not the first time with this chip. Suggest to move to another 4-20mA transceiver but I guess for your client it's too late. TI seems to have some logistics issues lately.

Farnell Asia says "awaiting delivery", whatever that means. Photo is deceiving, it is the DFN package:

Then there's the usual, have ma, dad, grandma and so on in his area register and order samples :-)

What kind of stories?

Unfortunately, that one is 'the' one. Without it the product can't exist :-(

Hmmm, why didn't I think of that? (already did it once, but shh!

Is this chip in high demand? Or is there another chip-de-jour that is preferred for 4-20mA applications? ...Jim Thompson

It was an engineer who asked whether I could consult and sent me his schematic. Later the boss didn't want to have an outsider involved so I didn't proceed. I saw this XTR thingie in there and urged them to design it out, prontissimo. But found them 1k of them in Italy (not DFN) as a courtesy, which they probably slurped up because they had some boards already made. The usual distributors were non-stock.

Well, there are still some (few) SOP packages available. Sure there isn't any other way to do this board? Otherwise you guys probably have to put in orders for oodles of these, wait until end of April, and then stash them all in a safe deposit box.

I think John Larkin had to do that with a Maxim part. Pretty sad state of affairs when semi mfgs announce nice parts and then can't deliver.

No idea, I don't do much 4-20mA stuff. But I certainly would not design in this one. I don't like boutique parts anyway ;-)

Mainly a space issue (really small and densely populated) and also that one also has a thermal pad. The MSOP, at more than 5x3, is... huge, 4-20 can dissipate quite a bit of power and case temp can go to 100°C. And some other issues, too... If it were possible, I'd have done it.

Yep, already told this.

Well, that would be the end of the rope then :-)

Or maybe not quite. I would talk to someone high up at TI, at least at the level of the sales manager for France. Discuss the situation, if needed drop a hint that word about this has spread (and about MSP430 delivery issues, all this not being so good for the corporate image and yada, yada, yada), and see if they can't speed up the foundry schedule for this part. LTC once did something similar for me and a client, I didn't want the DFN but the MSOP of a part because it's a hi-rel product where flexing must be tolerated. Got an answer next day and almost couldn't believe it: "Ok, we'll get some and stuff the channel at Digikey with MSOP if you want us to" ... Wow.

IME Texas hasn't been quite that customer-oriented in the last years but it cannot hurt to try. Essentially one phone call. Also, ask him if they have die and are willing to sell some. If the heat-sinking thing in there isn't too complex maybe you could have those finished at a packaging place to tide you over the three month wait.

^^^

Should have been a frownie :-(

Oh, snap.

Is this one of those things that has to live inside a 6mm (0.25") tube?

I doubt they (Burr-Brown) got much market penetration. In the process control market design lives are very long and there is little reason to change from (relatively) jellybean precision op-amps, references and discretes once a product is designed.

And newer stuff is moving away from analog 4-20mA to fieldbuse and other digital and hybrid analog/digital (eg. Hart) protocols.

No, it's not that one, and it sure wouldn't fit there with all the other components. Fortunately, the smaller ones are not 4-20mA and have direct analog output. Include protections, though...

One is already finished, one sided and 21 components on the 7mm dia. The other one is under development and is dual sided with 33 components. all that with the connection pads. All those mounted in a TO5 packaging. That's scary at first sight...

Hey, don't complain :-)

I am sitting here, looking at how to cram several hundred sense channels and more than a dozen amps into a tube that will be 2-3mm diameter. Oh, plus some digital stuff. Of course it'll be a chip but even that has its limits. Fighting the Rdson values right now.