Re: MOS8520R4 - 1988 vs. 1991

From: Pasi 'A1bert' Ojala <a1bert_at_iki.fi>
Date: Wed, 29 Jan 2020 16:08:52 +0200
Message-ID: <10eb6156-4e6e-2235-efe9-72cee4f27760_at_iki.fi>
On 29.01.2020 15:25, silverdr_at_wfmh.org.pl wrote:
>
>> On 2020-01-29, at 12:37, Frank Wolf <webmaster_at_frank-wolf.org> wrote:
>>
>> No... circuit seems to be identical.
>>
>> Though they changed the masks which was expensive they didn't want to
>> introduce new part numbers.
> No, but the revision would be expected to change, wouldn't it? It looks like a negligence to me. Might even be deliberate like with 8521s labeled as 6526s.
Seems like a yield improvement revision combined with cleaning up some 
layout errors. Some of the top metal traces of the original are bound to 
be susceptible to defects.

Lot numbers are used for this kind of yield/testability/reliability 
changes that are not visible to the end user.

The manufacturer knows which lot is produces with which masks.

-Pasi
Received on 2020-05-30 00:29:37

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