I would like to get a datasheet for a ST Micro product, I have attached a photo of the device

[Peter BENSCH · Accepted solution]

It's an LD1085CD-TR in DPAK (TO252) which has been already discontinued.
There is still the LD1085D2TR in D2PAK (TO263), but due to the bigger package it is not a drop-in replacement.
Does this answer your question?
Regards
/Peter

[Ksimp.1]

Yes it does Peter, thank you very much

Keith

[Peter BENSCH]

Great!
If the problem is resolved, please mark this topic as answered by selecting Select as best. This will help other users find that answer faster.
 
Thank you and regards
/Peter

[Ksimp.1]

Just one other question, the regulator comes in different voltages, do I have the LD1085CDT which is an adjustable voltage output?

[Tesla DeLorean]

These both look to be a fixed voltage, you should check the south pad is ground, or goes to ground via a resistor. The one on the top side, doesn't look to be a divider, and this likely a standard voltage supply rather than something novel.

This looks to have been worked over several times, are you sure there isn't something else amiss with the circuit. Perhaps sketch out a schematic as you can discern it.

[Peter BENSCH]

The LD1085C was only available as adjustable version in the DPAK. You could also use it as a constant current source, but as @Tesla DeLorean wrote, you should check to be sure that pin 1, the one in the photo below, is connected directly to GND. If that is true, then the LD1085C would regulate to 1.25V output voltag

But probably pin 1 is connected to the tab via a resistor of 100...200 ohms, across you'd get a drop of Vref=1.25V, so the resistor from pin 1 to GND sets the output voltage.

The probability for a defective LD1085C is quite low, because the LD1085C is internally protected against thermal overload. But you can test it quite easily for function at least by desoldering it, connecting it with pin 1 = GND and pin 3 = VIN to a voltage source, in addition a load resistor of approx. 5...10 Ohm to Tab and GND, over which then the regulated 1.25V must occur.

If you have to change the LD1085C and 1.5A is sufficient as output current, you can also use the LD1086DTTR.

At least in the photo, where the transistor Q13 is next to the LD1085C, the LD1085D2TR can be used alternatively, if you solder it in a little bit "crooked", so that there is no short at the vias.

Good luck!

Regards

/Peter