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From: mdeale@mira.acs.calpoly.edu (Myron Deale)
Newsgroups: comp.arch
Subject: Re: FRAM
Message-ID: <12110@polyslo.CalPoly.EDU>
Date: 20 Jun 89 04:43:05 GMT
References: <1012@aber-cs.UUCP> <1415@cbnewsh.ATT.COM> <19507@cup.portal.com>
Sender: news@polyslo.CalPoly.EDU
Reply-To: mdeale@mira.acs.calpoly.edu.UUCP (Myron Deale)
Organization: ACS, Cal Poly, San Luis
Lines: 37


Hello,

   FRAM's show much promise, we shall see if this is fulfilled. Two good
references that I've run accross are:

Horton, Richard and Castelberry, Randel. "Nonvolatile FRAMs fit standard
memory applications." Electronic Products, 6/1/88, pp. 41-47.

and

Evans, Joe. "Ferroelectric Memories." ESD: Aug. '88, pp. 29-35.

   The article by Horton covers the physics of FRAMs quite well in my
estimation. Some notes: the key ingredient seems to be lead-zirconate
titanate (PZT), which is used to form ferroelectric memory cells. Horton
works for Ramtron and their goal is an endurance of 10**15 memory cycles,
currently having achieved 10**11 cycles. This is for the prototype 256
bit (2**8) part. May have scaling problems?

   Evans works for Krysalis. Their K28C16 2Kx8 UniRAM nonvolative SRAM
with 250ns cycle time "is designed to allow 10**9 power cycles and have
one-year retention of state powered-down." The ferroelectric memory is
only accessed during power-up or power-down. Evans notes "10**12 accesses
in 10 years requires 3000 accesses per second constantly on a single byte."

   In addition, FRAM density should be superior to EEPROM. These companies
currently need to work on manufacturing processes. I think I read some-
where that these companies have signed on a few heavy-weights to help
develop the products and bring them to market (eg. ATT?).

Myron
// disclaimer: I have nothing to do with either Ramtron or Krysalis except
   I like what they make. In addition, the above info is a year old. I
   expect Michael Slater to have more current info (whom I have nothing to
   do with except I like uReport). "And futhurmore, I have nothing to ..."
// live free or die, Open Letter, Living Color.