Significance of IC markings?

[Solidhex]

Can anyone tell me what the significance of the numbering at the top of an IC?
The "JM16AB" part? Does it reference any particular quality of the part or is it just a manufacturing date thing?

[StereoKills]

It is most likely the manufacturer's lot number.

[PRR]

The "galaxy" "N" means it was made/marked by National Semiconductor. Ask them what that stuff means. I found this:

http://www.national.com/analog/quality/marking_conventions

I can't decode your chip from that clue, but it is surely where and when it was made, so they can trace a bad batch.

It *may* say:
Fab: J Greenock, UK
Assembly: M Malacca, Malaysia

> any particular quality of the part

What is "quality"??

If you mean "audio sweetness".... no. They don't test for that, and would not know good audio quality if it bit them in the ear.

Their notion of "quality" is defined in the spec-sheet:
http://www.national.com/ds/LM/LM741.pdf

--and sub-classed for specific uses:

"A" has low DC errors. "not-A" has higher DC error. "C" can have slightly higher DC error. This error does NOT affect audio sound.

The "C" also means commercial temperature range (not industrial or military). If you work between 32F and 158F, this is all you need (and a LOT cheaper than -67F to 257F rating).

The "N" means Plastic DIP package (not round-metal, not ceramic).

It is *entirely* possible the chip could meet a higher spec. Most "C" 741s meet the "A" spec for input offset voltage. Very few exceed the "A" spec for input bias current. And if you must play in a 160 degree room, a plastic DIP will usually work for many years; you just can't complain to National if it doesn't.