Features
• Serial Peripheral Interface (SPI) Compatible
• Supports SPI Modes 0 (0,0) and 3 (1,1)
• Medium-voltage and Standard-voltage Operation
– 5.0 (VCC = 4.5V to 5.5V)
– 2.7 (VCC = 2.7V to 5.5V)
• 3 MHz Clock Rate
• 64-byte Page Mode and Byte Write Operation
• Block Write Protection
– Protect 1/4, 1/2, or Entire Array
• Write Protect (WP) Pin and Write Disable Instructions for
both Hardware and Software Data Protection
• Self-timed Write Cycle (5 ms Typical)
• High-reliability
– Endurance: 100,000 Write Cycles
– Data Retention: >200 Years
• 8-pin PDIP, 8-pin JEDEC SOIC and 8-pin EIAJ SOIC Packages
SPI Serial
Automotive
EEPROMs
128K (16,384 x 8)
256K (32,768 x 8)
Description
The AT25128/256 provides 131,072/262,144 bits of serial electrically-erasable pro-
grammable read only memory (EEPROM) organized as 16,384/32,768 words of 8 bits
each. The device is optimized for use in many industrial and commercial applications
where low-power and low-voltage operation are essential. The devices are available in
space saving 8-pin PDIP (AT25128/256), 8-pin JEDEC SOIC (AT25128) and 8-pin
EIAJ SOIC (AT25256) packages. In addition, the entire family is available in 5.0V
AT25128
AT25256
(4.5V to 5.5V) and 2.7V (2.7V to 5.5V) versions.
Continued
Pin Configurations
8-pin PDIP
Pin Name
Function
CS
Chip Select
CS
SO
1
2
3
4
8
7
6
5
VCC
HOLD
SCK
SI
SCK
SI
Serial Data Clock
Serial Data Input
Serial Data Output
Ground
WP
GND
SO
GND
VCC
WP
8-pin SOIC
Power Supply
Write Protect
Suspends Serial Input
No Connect
CS
SO
1
2
3
4
8
7
6
5
VCC
HOLD
SCK
SI
WP
HOLD
NC
GND
DC
Don't Connect
Rev. 3262A–SEEPR–02/02
1