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June 8th, 2010 ~ by admin

Unlocking EPROM cores?

Its well known that manufacturers such as Intel and AMD will sell quad cores as dual cores, or 6-cores as quad-cores in order to meet demand, or to use dies that didn’t ‘make the cut.’ This process has been going on for over 30 years though. Back in the 70’s and 80’s it was very common for a device such as this:

Intel D2704 4k EPROM

Which is a 2704 4k EPROM, to actually be made from a 2708 die, just with not all the leads connected, or sometimes, with them connected but just labeled as the smaller part. In a production environment, it is cheaper to have a single production line making dies that can be used in more then one device, then having an entire seperate production line just to make a product that may not be the most popular.  Look at this die shot (its a bit blurry) but you can see its a 2708 die.

2704 with 2708 die

Once again, whats new, really isn’t we have just went from small EPROMs, to CPUs with billions of transistors


2 Responses to Unlocking EPROM cores?

  1. Marcus Simons

    We are restoring old GRETAG equipment with 8080 from 1978 (!) They were early ! I was looking for the 2704 and 2708 EPROM data sheet from different brands: Signetics and Intel. Maybe it is a good idea for you to add data sheets to your website? Would be lovely to create a good reference for everyone trying to restore old gear like we do. Just a small idea 😉

  2. Soviet K573RF23 and the Mark of Quality | The CPU Shack Museum

    […] by the adding of the 3 to the part number.  This certainly was not an uncommon procedure, even Intel regularly sold 2708 EPROMs as 2704s, whether to use a die with an imperfection, or to simply meet […]

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