Difference between same chips ?

[menjic]

I am relatively new to all this and relatively bad in writing English and I hope you will understand my question.

Maybe I ask too much but can not find anything on this topic, and can not stop asking my self if they are all identical why they are labeled different, or in another words can 2 factories produce identical chips ?

For example, is there any difference among these :

Chip 1. LM4870 JM34ES
Chip 2. LM4870 PM65RA
Chip 3. LM4870 PM35AK

There must be some kind of tolerance % in manufacturing process ?

In data sheet : IF military or aerospace specified devices are required please contact for availability and specification ???

What is military spec LM4870 ?

[abraxalito]

Yes, there are manufacturing tolerances and those are taken care of in the datasheet, by specifying maximums and minimums. The letters you see after the part number are lot codes (or date codes) giving some traceability. No two chips even from the same factory are absolutely identical in every respect, but that doesn't matter provided they meet the specifications in the datasheet.

Military spec would be higher reliability, more stringent testing (and hence much higher price). Not of interest to DIYers

[KSTR]

Device Marking Conventions | National Semiconductor

[marce]

Military spec is a bit of a misnomer, as there are very few mil spec devices produced these days ther is no market for them like there use to be, but we still require parts for mil/areo/medical (ie life critical designs) so you often have to talk to chip manufacturers about your design requirements. Generaly these parts are tested more and also are the best out of any batches. You will not see these parts on general sale, you have to involve the chip manufacturers in your design work. Automotive range parts tend to be the BEST of the off the shelf parts (better temp range etc).
A lot of mill design is done with Inductrial grade parts or automotive...