Pre-Production
FM25256
256Kb FRAM Serial 5V Memory
Features
256K bit Ferroelectric Nonvolatile RAM
• Organized as 32,768 x 8 bits
• Virtually Unlimited Endurance (1014 Cycles)
• 10 Year Data Retention
• NoDelay™ Writes
• Advanced High-Reliability Ferroelectric Process
Write Protection Scheme
• Hardware Protection
• Software Protection
Wide Operating Range
• Wide Voltage Operation 4.0V – 5.5V
Industry Standard Configurations
• Industrial Temperature -40°C to +85°C
• 8-pin SOIC (-S)
• “Green” 8-pin SOIC (-G)
Very Fast Serial Peripheral Interface - SPI
• Up to 15 MHz Frequency
• Direct Hardware Replacement for EEPROM
• SPI Mode 0 & 3 (CPOL, CPHA=0,0 & 1,1)
Description
Pin Configuration
The FM25256 is a 256-kilobit nonvolatile memory
employing an advanced ferroelectric process. A
ferroelectric random access memory or FRAM is
nonvolatile and performs reads and writes like a
RAM. It provides reliable data retention for 10 years
while eliminating the complexities, overhead, and
system level reliability problems caused by
EEPROM and other nonvolatile memories.
Unlike serial EEPROMs, the FM25256 performs
write operations at bus speed. No write delays are
incurred. The next bus cycle may commence
immediately without the need for data polling. The
next bus cycle may start immediately. In addition, the
product offers virtually unlimited write endurance.
Also, FRAM exhibits much lower power
consumption than EEPROM.
rn
te
The FM25256 provides substantial benefits to users
of serial EEPROM as a hardware drop-in
replacement. The FM25256 uses the high-speed SPI
bus, which enhances the high-speed write capability
of FRAM technology. Device specifications are
guaranteed over an industrial temperature range of
-40°C to +85°C.
This is a product in the pre-production phase of development. Device
characterization is complete and Ramtron does not expect to change the
specifications. Ramtron will issue a Product Change Notice if any
specification changes are made.
Rev. 2.4 (obsolete)
Feb. 2009
1
8
VDD
SO
2
7
HOLD
WP
3
6
VSS
4
SCK
SI
6B
25
5
25
FM
:
Pin Name
/CS
/WP
/HOLD
SCK
SI
SO
VDD
VSS
ve
ti
a
These capabilities make the FM25256 ideal for
nonvolatile memory applications requiring frequent
or rapid writes or low power operation. Examples
range from data collection, where the number of
write cycles may be critical, to demanding industrial
controls where the long write time of EEPROM can
cause data loss.
Al
CS
Function
Chip Select
Write Protect
Hold
Serial Clock
Serial Data Input
Serial Data Output
Supply Voltage (4.0 to 5.5V)
Ground
Ordering Information
FM25256-S
FM25256-G
8-pin SOIC
“Green” 8-pin SOIC
Ramtron International Corporation
1850 Ramtron Drive, Colorado Springs, CO 80921
(800) 545-FRAM, (719) 481-7000
www.ramtron.com
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