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pphillips12
Joined: 01 Nov 2003
Posts: 139
Location: USA
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 Posted: Sat Sep 16, 2006 9:36 am Post subject: New chip in my collection:) |
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Note it's a 3301 not the later 3301A...
Wonder how many of these are still floating around. This is the only one I've ever seen.
Strange that wepwawet has a 3301A dated 7217 but this 3301 is dated 7317?
The 3301A data sheet says it's a "higher speed" version of the 3301. Maybe Intel speed binned "off the shelf" standard config. 3301A's and those that those that did not pass the test were downgraded to 3301's? |
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chip68
Joined: 19 Oct 2004
Posts: 1024
Location: Central Pennsylvania
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| Posted: Sat Sep 16, 2006 10:42 am Post subject: |
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I don't think we've definitively established that 7217, 7317, etc. are date codes on these older Intel chips. There was some discussion of those codes in another thread, and no clear consensus was reached, nor any documentary evidence offered one way or the other.
It's a common practice for a company to continue to manufacture "legacy" devices (e.g., 3301) for several years even after they're no longer listed in product catalogs and are supplanted by improved versions. The 3301(A) is a bipolar part, which - unlike MOS devices at the time - had very consistent specs from one lot to another and very high yields. I doubt they were speed-graded as you suggest.
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pphillips12
Joined: 01 Nov 2003
Posts: 139
Location: USA
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| Posted: Sat Sep 16, 2006 11:04 am Post subject: |
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I have some chips with what appears to be a date code on the cap that also have a date code on the bottom and they are not the same date (a few months apart). Maybe the package date is when the ceramic package was made and the date on the cap was when the chip was actually assembled and capped?
The data sheet for the 3301A says it's a direct pin for pin replacement for the 3301 so I'm not sure why Intel would continue making the 3301 a year after the 3301A was available unless they were sitting on a large quantity of unpackaged 3301's dice and were packaging them and selling them cheaper than the 3301A's? |
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chipcollector
Joined: 28 Sep 2004
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Location: New England
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chip68
Joined: 19 Oct 2004
Posts: 1024
Location: Central Pennsylvania
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| Posted: Sat Sep 16, 2006 11:32 am Post subject: |
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| pphillips12 wrote: | | I'm not sure why Intel would continue making the 3301 a year after the 3301A was available |
Remember that the 3301(A) is mask-programmed, which essentially means it's a custom part. So when a customer needs another batch of the same ROM, Intel pulls the existing mask set and basically re-manufactures the old IC. Unless the difference between a 3301 and a 3301A is purely process-related, as opposed to a layout or design tweak, you'd have to generate a whole new metal mask to upgrade to the 3301A, which is a fairly expensive proposition.
But as I said, IC manufacturers often continue to make certain parts for years after they've become obsolete. (Some military contracts require this. The SN3xx/5xx logic chips TI introduced in 1962, for example, were still being made well into the late-1970s.) In some cases you'll see such parts listed in data books as "not recommended for new designs."
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pphillips12
Joined: 01 Nov 2003
Posts: 139
Location: USA
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| Posted: Sat Sep 16, 2006 11:39 am Post subject: |
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Pull the existing mask set and basically re-manufactures the old IC...
Didn't think about that. That probably explains it. |
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chip68
Joined: 19 Oct 2004
Posts: 1024
Location: Central Pennsylvania
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| Posted: Sat Sep 16, 2006 1:20 pm Post subject: |
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Any idea what that particular ROM was used in?
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wepwawet
Joined: 18 Mar 2004
Posts: 3019
Location: Seligenstadt - Germany
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| Posted: Sun Sep 17, 2006 2:41 pm Post subject: |
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As my 3301A's printings like 7217 fit together on a board with seven 3301As all close together AND the TI logic chips fit AND there is a stamped date on the side on the doard I bet the whole board that this is a date code.
There are many other markings on other chips I agree to doubt they are date codes.
At my point of view this 3301 is newer than some 3301As but chip68 gave a reasonable answer.
Anyway, a great chip!
Did you get it from Brian? - he had one before his account was killed. |
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pphillips12
Joined: 01 Nov 2003
Posts: 139
Location: USA
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| Posted: Sun Sep 17, 2006 3:10 pm Post subject: |
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| Yes, got it from Brian. Was kinda worried because his account got killed right after I mailed him a money order for the chip but he sent it without any problems. Not sure what was going on with him and EBAY. |
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chip68
Joined: 19 Oct 2004
Posts: 1024
Location: Central Pennsylvania
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| Posted: Mon Sep 18, 2006 10:26 am Post subject: |
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| wepwawet wrote: | | As my 3301A's printings like 7217 fit together on a board with seven 3301As all close together AND the TI logic chips fit AND there is a stamped date on the side on the doard I bet the whole board that this is a date code. |
Could be. I did notice that quite a few mask ROMs (1301, 3301, and 4001) appear to be date coded. OTOH, many Intel chips from the same time period have no date top or bottom - just a batch code, some of which could easily be confused for a date code (e.g., B7119). I think the moral of the story is, if you've got an isolated Intel chip from the early '70s, you can't necessarily assume that any 4-digit code beginning with the number "7" is a date code... You have to look at other clues, like chips on the same board or board manufacturing date, etc.
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wepwawet
Joined: 18 Mar 2004
Posts: 3019
Location: Seligenstadt - Germany
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| Posted: Mon Sep 18, 2006 10:34 am Post subject: |
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pretty good conclusion.
it contains the idea to keep chips on boards and not to desolder or pull them:-)
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