Wow. How did you get to the client meeting in Colorado? Did you drive all that? I mean, it's a very scenic drive but still...
Anyhow, be prepared for even tougher "new rules". No more than 3oz water bottles, toothpaste might be considered dangerous goods etc. One can live with all that but it does get old after a while. And expensive because now you have to buy stuff behind the checkpoint at a few hundred percent markup. And I liked those sandwiches with thin slices of roast that I barbequed myself :-(
On Fri, 20 Oct 2006 15:50:17 GMT, Joerg wrote in Msg.
I have followed this thread with some interest. What I don't understand is why you use an LDO in the first place if you have to drop a large voltage anyway by adding a series zener. Or is it that the only regulator that otherwise fits your specs happens to be an LDO?
Well, I hate LDOs. However, in this case I needed a regulator with an extremely low quiescent current (well under 5uA) and this regulator was the only one that qualified. Unfortunately it is also an LDO :-(
I would have normally not used it based on the fact that it is an LDO, and would have rolled my own instead. Would have been lower in cost as well. However, there was not enough space.
I15 to Barstow, I40 thru Needles, Kingman to Flagstaff, North on AZ64 for about 70 miles and if you don't stop in time, you fall into it.
No matter how many times you see it, you never remember how big it is.
--
"Electricity is of two kinds, positive and negative. The difference
is, I presume, that one comes a little more expensive, but is more
durable; the other is a cheaper thing, but the moths get into it."
(Stephen Leacock)
-- "Electricity is of two kinds, positive and negative. The difference is, I presume, that one comes a little more expensive, but is more durable; the other is a cheaper thing, but the moths get into it." (Stephen Leacock)
But once you've hiked all the way down and back up in one day you'll always painfully remember how big it is ;-)
Especially after you hiked it the wrong way around like I did the very first time, down the Bright Angel Trail and up the really steep Kaibab Trail. When someone down at the river told us "You've got to be kidding" I had no clue what they meant. After the hike back up I knew.
Well, as promised I wanted to let you guys know what came of all this. Turns out the old batch regulators took out several chips and semiconductors when they blew. With the latest shipment from Digikey it all works fine now. Since they come w/o lot codes it's hard to see what happened, other than that the regulators had a melt-down.
For now, yes. Forever? That is something one can never guarantee. That's why endurance tests are running right now.
Well, there are situations where you only have the aftermath as evidence and must to try to find out what happened. Like which devices gave up etc. Very similar to investigating tire incidents where all you have are the shreds ;-)
When you find several blown devices on a board and these are the ones that would go first in case of overvoltage it's pretty clear what happened. So yes, we do have a clue. Just not as much as we had hoped for. Endurance tests will follow, as that is where the failures had happened. Yesterday we built several devices and tried to make them fail via load transients etc. They didn't fail anymore but this kind of testing needs to continue.
yes but you don't know if the "new" batch of chips just happen to be better because Joe Schmoe coughed into the silicon furnace on that batch.
I recently measured some MPSA42 transistors that should not have survived in one particular 450V circuit. Their spec is 300V min, but my batch didnt avalanche until 840 plus or minus 20 volts!
You'll be in a real pickle if you lower your guard and the next batch of chips just meets specs, or worse yet, lowers some undocumented spec like the SOA.. You won't have anybody to blame.
What alternatives would there be? I can't control TI's clean room since I am not in charge of production there. But I am sure they run a squeaky clean operations. It's a really good company. If their P/E ratio wouldn't be above 15 I'd even buy shares into my IRA.
It's the only chip that can regulate while not consuming more than 3uA Iq when not under load. The data sheet is a bit brief but that's the case for most other LDO. We run it well below any of its limits. Nothing gets hot in there. No ESD can reach the regulator. The load is carefully "greased on", not hard switched. Bottomline there isn't much more we can do other than rolling our own discrete regulator. Which we might just do.
I would really like to have more info on the loop stability range versus ESR. But IMHO that is one of the not so positive sides of TI. It is very tough and sometimes impossible to obtain docs beyond their published data. This has cost them some sales already (in my case lost MSP430 design-ins) but I doubt things will change. Very different scenario with smaller suppliers. The same client had a diode issue. Big mfg showed a cold shoulder, no indepth data, no real support. Contacted two smaller ones and they sent me whatever I wanted, had their engineers perform test-runs and shared the results with me etc. Problem solved. Guess which vendor was ditched?
Excuse an old cynic, but the other possibility is finger trouble.... downstream components already damaged by electrostatic charge before power is first switched onto them, output shorts caused by careless prodding around with DVM/oscilloscope probes, or even a reversed power supply.
Yes, but they are pretty careful. Also, some of the units ran for a little while and then quit out of the blue. The only thing that changes during those tests is the supply voltage (slowly drops) and the load.
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