In ancient Egypt, the Horus of Gold
represented a form of a pharaoh’s name
most typically thought to mean “superior
to his foes” and associated with
eternity. These qualities would be highly
desirable in any nonvolatile memory (NVM)
product. Now suppose you could take a
standard serial flash memory and add virtually unlimited endurance and the ability to
perform write operations at bus speed. That’s
right—no write delays after data reaches the
memory device, and nearly endless stamina.
How can this be accomplished with flash
memory? It can’t, unless you change the
material and structure of the underlying device. Replace the flash-based cells with ferroelectric-
based cells and you get ferroelectric
RAM (FRAM). Unlike serial flash, FRAM can
perform write operations at bus speed. Out
are the typical write delays associated with
flash, and in is the ability to conduct the next
bus cycle without any data polling.
Ramtron’s FRAM-based, 2-Mbit (256 by 8)
FM25H20 can be accessed using an industrystandard
serial peripheral interface (SPI) or
SPI bus. It provides 10 years of data retention
and 100 trillion (1014) read/write cycles. Also,
it alleviates the overhead and complexities of
using serial flash.
FRAM offers orders of magnitude more
endurance than serial flash while using less
power. The FM250H20 draws a sleep current
of 3 µA and a standby current of 80 µA.
Additionally, it requires less than 10 mA for
read/write operations at 40 MHz. So if your
next design will require frequent or rapid
write capability or you need to lower your
power profile, consider using FRAM. Potential
applications include very small storage
devices that require many write cycles and
industrial controls that may not tolerate the
longer write times of serial flash.
“The 2-Mbit serial FRAM is a natural extension
for our metering and printer customers
who want to increase data-collection capacity
in their next-generation applications without
increasing board space. The FM25H20
offers our half-megabit serial FRAM customers
quadruple the memory in the same small
footprint,” says Duncan Bennett, Ramtron’s
strategic manager. “In addition to enhancing
existing systems, this technological development
moves FRAM into a range of new
markets that require a low-power memory in
a very constrained space, such as portable
medical devices.”
Samples of the FM25H20 are available in an
eight-pin, 5.0- by 6.0-mm RoHS-compliant
(Restrictions on Hazardous Substances) thin
dual-inline flat (TDFN) package (footprint
compatible with SOIC-8) in an industrial
temperature range of –40°C to 85°C (see the figure). Pricing starts at $10.20 for quantities
of 10,000 units.
RAMTRON
www.ramtron.com