Discontinued IC's: Fairchild (?) MB15604; FPGA?

From: Eric Smith <eric_at_brouhaha.com>
Date: Tue Aug 1 17:25:34 2000

> Why the terms PGA != PLA != PLD != ???

PGA is a Pin Grid Array, which is a package type. No direct relation to
the other terms.

A PLA is a Programmable Logic Array. It has a programmable OR
matrix followed by a programmable AND matrix. This is the most
general combinatorial logic device, but has mostly been replaced by
PAL, CPLDs, etc.

An FPLA is a Field-Programmable Logic Array. There used to be
mask-programmable logic arrays, but they're not really available
as standalone parts any more, so the term FPLA has mostly fallen
out of use.

A PAL is like a PLA but with the AND matrix fixed.

A PLD is a Programmable Logic Device, and can be almost anything.

A CPLD is a Complex Programmable Logic Device, which just means one
with lots of pins or terms. There's no well-defined threshold beyond
which a PLD becomes a CPLD.

An EPLD is an Erasable Programmable Logic Device. Since almost all
current stuff is electrically erasable, this term has mostly fallen
out of use.

An FPGA is a Field-Programmable Gate Array. These typically are
"finer-grained" than a CPLD; they have simpler logic elements, but
more of them, and more routing resources.

> Does this just represent different
> manufacturers trying to control
> market lingo?

Maybe. But mostly I think it's more a matter of the lack of standardization,
rather than attempted "control".
Received on Tue Aug 01 2000 - 17:25:34 BST