Features
• Serial Peripheral Interface (SPI) Compatible
• Supports SPI Modes 0 (0,0) and 3 (1,1)
– Data Sheet Describes Mode 0 Operation
• Medium-voltage and Standard-voltage Operation
– 5.0 (VCC = 4.5V to 5.5V)
– 2.7 (VCC = 2.7V to 5.5V)
• Automotive Temperature Range −40°C to +125°C
• 5 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 max)
• High Reliability
– Endurance: 1 Million Write Cycles
– Data Retention: >100 Years
• 8-lead PDIP, 8-lead JEDEC SOIC, and 8-lead TSSOP Packages
SPI Serial
Automotive
Temperature
EEPROMs
128K (16,384 x 8)
256K (32,768 x 8)
Description
The AT25128A/256A 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 automotive applications
where low-power and low-voltage operation are essential. The devices are available in
space-saving 8-lead PDIP, 8-lead JEDEC SOIC, and 8-lead TSSOP packages.
AT25128A
AT25256A
The AT25128A/256A is enabled through the Chip Select pin (CS) and accessed via a
three-wire interface consisting of Serial Data Input (SI), Serial Data Output (SO), and
Serial Clock (SCK). All programming cycles are completely self-timed, and no sepa-
rate erase cycle is required before write.
Table 1. Pin Configurations
8-Lead PDIP
Pin Name
CS
Function
1
2
3
4
8
7
6
5
CS
SO
WP
VCC
HOLD
SCK
SI
Chip Select
SCK
SI
Serial Data Clock
Serial Data Input
Serial Data Output
Ground
GND
SO
8-lead SOIC
GND
VCC
WP
CS
SO
WP
VCC
1
2
3
4
8
7
6
5
Power Supply
Write Protect
Suspends Serial Input
No Connect
HOLD
SCK
SI
GND
HOLD
NC
8-lead TSSOP
DC
Don't Connect
1
2
3
4
8
7
6
5
CS
SO
WP
VCC
HOLD
SCK
SI
GND
5088E–SEEPR–10/05
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