From: "Jonathan Bromley"
Subject: Re: AMD AM27C256-55DC
Date: Fri, 10 Jan 2003 14:30:20 -0000
Reply-To: "Jonathan Bromley"
NNTP-Posting-Date: Fri, 10 Jan 2003 14:30:20 +0000 (UTC)
X-Newsreader: Microsoft Outlook Express 5.50.4807.1700
> I don't have an old catalog and cannot find this on the AMD web site.
> Can anyone confirm that the -55 means its a 55ns part for the
55 = 55ns access time. /OE true to valid output may well be
quite a lot shorter, but you must have the address and /CE
valid for at least 55ns in order to get valid data.
DC = cerdip package, commercial temp range.
The numeric speed grades were in principle arbitrary, but
in practice self-evident.
AMD's 256k EPROMs were unique in that they are SPECIFIED
to work correctly regardless of the 0/1 logic level on the
Vpp pin (pin 1 IIRC) during normal operation. Most other
manufacturers required you to keep Vpp at logic 1, which
made it a PITA to create 28-pin socket sites that were
compatible with both 256K and 512K EPROMs.
Jonathan Bromley, Consultant
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