I'm still waiting for the Spice model for the 8078. I think I can make it do positive to dual negative conversion.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
onsdag den 19. februar 2020 kl. 19.35.39 UTC+1 skrev John Larkin:
Those little switching regulators blow me away. They do take some of the fun out of on-board power supply design though.
The ripple could be better and sometimes the maximum load capacitance is a bummer, but they can really speed up some designs.
We often do that here. But I want the cute little dual LTM to make two different negative rails. I'd like to Spice that, because the BGA is hard to breadboard.
I'd love to x-ray the LTM8078. How can they do that?
Does anyone have a high-res x-ray? Ours is a big parts counter and doesn't have useful resolution for ICs.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
onsdag den 19. februar 2020 kl. 20.04.50 UTC+1 skrev John Larkin:
try a dentist?
They are very quiet too. The nasty circulating currents are mostly local to the brick.
The 8078 is amazing, but it does need external caps. Neither the Spice model nor the eval board seem to be ready.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Upon first (quick) glance of the spec sheet PDF, I thought the MTBF was only 4.5 minutes. :)
Thankfully, it's much higher than that.
But, an X-ray will only show leads and little squares where the silicon is. It's not likely to distinguish wiring or doping, unless you first strip off the epoxy and do fluorescence microprobing.
For the kind of resolution that would find component parts of an IC, you'd have to hang out at a synchrotron next to the X-ray laser.
Better to use an electron microscope (you still have to strip the epoxy). Either way, synchrotron or microscope, you're doing it with vacuum tubes.
The inductors would be interesting in LTM8078.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
That's probably why they have that breakout board.
It looks like it would work, but your middle voltage would be loading the bottom voltage...
When I tried that same trick with a LM2596HV trying to make -36V from
+12V it made smoke instead. rather than risk more parts trying to figure out why I found a different solution.Do what? the datasheet implies that there's a 0.32mm thick PCB with the semiconductors and the inductors mounted on it. it looks like they used green solder mask.
how much do these things cost that you're not prepared to cut one open?
-- Jasen.
We have the eval board on order, but everything is grounded, so it can't be used as a pos-to-neg converter, much less a dual.
We do this a lot
and it always works. The extra ferrite beads are to keep switcher noise down; there is delicate stuff nearby.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
whit3rd wrote in news: snipped-for-privacy@googlegroups.com:
Nobody reverse engineers chips any more. At least not anything with any appreciable density. Too many layers. Too much cost and by the time you finish, the chip you are trying to hack out is obsolete.
No LTM8078s around here, but here is an LTM8049 from my parts drawer:
These are handy because they can be used as dual SEPIC or inverting regulators, or any combination thereof. Especially good for those cases where you want a given output rail that lies within the expected input range. There is no drama or transitional behavior as the input voltage crosses the output voltage, it just works.
-- john, KE5FX
The older LTM bricks were LGAs, which didn't block the x-ray view like the solder balls do. But then, they made shorts on the PC board.
Here's a SEPIC that's adjustable from 0 to +70 volts out, set with a local pot or a customer input. What's useful is that it runs with essentially a constant-power limit.
-- John Larkin Highland Technology, Inc The cork popped merrily, and Lord Peter rose to his feet. "Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.