Preliminary
This is a product that has fixed target specifications but are subject
Ramtron International Corporation
to change pending characterization results.
1850 Ramtron Drive, Colorado Springs, CO 80921
(800) 545-FRAM, (719) 481-7000
www.ramtron.com
Rev. 1.0
Aug. 2004
Page 1 of 13
FM25W256
256Kb FRAM Wide Voltage Serial Memory
Features
256K bit Ferroelectric Nonvolatile RAM
•
Organized as 32,768 x 8 bits
•
Unlimited Read/Write Cycles
•
10 Year Data Retention
•
NoDelay™ Writes
•
Advanced High-Reliability Ferroelectric Process
Very Fast Serial Peripheral Interface - SPI
•
Up to 25 MHz Frequency
•
Direct Hardware Replacement for EEPROM
•
SPI Mode 0 & 3 (CPOL, CPHA=0,0 & 1,1)
Write Protection Scheme
•
Hardware Protection
•
Software Protection
Wide Operating Range
•
Wide Voltage Operation 2.7V – 5.5V
Industry Standard Configurations
•
Industrial Temperature -40
°C to +85°C
•
8-pin SOIC (-S)
•
“Green” 8-pin SOIC (-G)
Description
The FM25W256 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 FM25W256 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.
These capabilities make the FM25W256 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.
The FM25W256 provides substantial benefits to
users of serial EEPROM as a hardware drop-in
replacement. The FM25W256 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.
Pin Configuration
Pin Name
Function
/CS
Chip Select
/WP
Write Protect
/HOLD
Hold
SCK
Serial Clock
SI
Serial Data Input
SO
Serial Data Output
VDD
Supply Voltage (2.7 to 5.5V)
VSS
Ground
Ordering Information
FM25W256-S
8-pin SOIC
FM25W256-G
“Green” 8-pin SOIC
CS
SO
WP
VSS
VDD
HOLD
SCK
SI
1
2
3
4
8
7
6
5
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
