Hello! Would you be able to confirm that the marking in the device pictured is in fact LM7805CT? I assume it is despite omitting the ‘T’ on the device body (which would be for packaging “Tube” anyway), but wanted to double check since I couldn’t find any matching On Semi documentation.
Many thanks in advance!
Nick Capone
Component Engineer
Intervala, LLC
Device markings generally don’t include indication of the packaging they were transported in, since it’s irrelevant to the function of the device itself.
78xx series regulators were invented shortly after the wheel and fire… Documentation for such is likely to have gone through a large number of corporate acquisitions at this point, without receiving a whole lot of care.
Part marking information for this part is on page 28 of the datasheet: MC7800 - 1.0 A Positive Voltage Regulators (digikey.com)
It actually was the different device marking described on page 28 of that PDF that caused me to question what the marking should actually be. I think it’s different on that PDF since it’s not the datasheet for the part but rather the datasheet for a suggested replacement. Correct datasheet below:
LM78XX.pdf (2.3 MB)
My apologies that is the datasheet we have linked to LM7805CT from onsemi, I am not sure why we do not have the original datasheet. The part marking on your part indicates an onsemi part, not a Fairchild part. This is somewhat irrelevant because the two companies have merged, and according to this PCN the Fairchild part is now marked with the onsemi logo… However our system indicates the onsemi part is obsolete but the Fairchild part is active. Unfortunately the part number only brings up a recommended replacement on their website. There is likely another datasheet somewhere that has current marking information, but I have been unable to locate it. Many companies also stopped releasing part marking information due to counterfeiting, so that is a possibility as well.
