DEC 11/70...

From: Philip.Belben_at_powertech.co.uk <(Philip.Belben_at_powertech.co.uk)>
Date: Mon Apr 6 12:50:23 1998

> Date codes are stamped on just about every IC, and some other parts too.
>
> They are generally a four digit number of the form YYWW, where YY is the
> last two digits of the year in which the chip was munfactured and WW the
> week number, from 01 through 52.
>
> Examples would be "7830" for the 30th week of 1978, and "8101" for the
> first week of January 1981.
>
> Generally for the old machines we talk about on this list, the chip type
> code is easy to differentiate from the date code, because of the
> prevalence of 7400-series TTL chips. Any 74xx or 54xx number will be the
> chip type, while the other number will be the date code.

I learnt this one in a DEC PDP11-05. The chips are TTL - 74xx not
74LSxx or anything else - and almost every date code is in 1974. (i.e.
also 74xx). The trick is that the chip no. usually has manufacturers
name codes, package codes etc. embedded, e.g. SN7400N for one of the TI
packages (I forget which!), while the date code in my experience never
does. Be warned! I read somewhere (Horowitz and Hill?) that many
distributors got this wrong in 1974 and shipped the wrong chips...

Philip.
Received on Mon Apr 06 1998 - 12:50:23 BST