25AA256/25LC256
256K SPI™ Bus Serial EEPROM
Device Selection Table
Part Number
VCC Range
Page Size
Temp. Ranges
Packages
25LC256
25AA256
2.5-5.5V
1.8-5.5V
64 Byte
64 Byte
I, E
I
P, SN, ST, MF
P, SN, ST, MF
Features
Description
• Max. clock 10 MHz
The Microchip Technology Inc. 25AA256/25LC256
(25XX256*) are 256k-bit Serial Electrically Erasable
PROMs. The memory is accessed via a simple Serial
Peripheral Interface™ (SPI™) compatible serial bus.
The bus signals required are a clock input (SCK) plus
separate data in (SI) and data out (SO) lines. Access to
the device is controlled through a Chip Select (CS)
input.
• Low-power CMOS technology
- Max. Write Current: 5 mA at 5.5V, 10 MHz
- Read Current: 5 mA at 5.5V, 10 MHz
- Standby Current: 1 µA at 5.5V
• 32,768 x 8-bit organization
• 64 byte page
• Self-timed ERASE and WRITE cycles (5 ms
max.)
Communication to the device can be paused via the
hold pin (HOLD). While the device is paused,
transitions on its inputs will be ignored, with the
exception of Chip Select, allowing the host to service
higher priority interrupts.
• Block write protection
- Protect none, 1/4, 1/2 or all of array
• Built-in write protection
The 25XX256 is available in standard packages
including 8-lead PDIP and SOIC, and advanced
packaging including 8-lead DFN and 8-lead TSSOP.
Pb-free (Pure Sn) finish is also available.
- Power-on/off data protection circuitry
- Write enable latch
- Write-protect pin
• Sequential read
• High reliability
Package Types (not to scale)
- Endurance: 1,000,000 erase/write cycles
- Data retention: > 200 years
- ESD protection: > 4000V
• Temperature ranges supported;
TSSOP
(ST)
PDIP/SOIC
(P, SN)
CS
SO
WP
VCC
1
2
3
4
8
7
6
5
1
2
3
4
8
7
6
5
CS
SO
WP
V
CC
- Industrial (I):
- Automotive (E):
-40°C to +85°C
-40°C to +125°C
HOLD
SCK
SI
HOLD
SCK
SI
VSS
• Standard and Pb-free packages available
VSS
Pin Function Table
DFN
(MF)
Name
Function
Chip Select Input
1
2
3
4
CS
8
7
6
5
VCC
HOLD
SCK
SI
CS
SO
SO
WP
VSS
Serial Data Output
Write-Protect
Ground
WP
VSS
SI
Serial Data Input
Serial Clock Input
Hold Input
SPI is a registered trademark of Motorola Corporation.
SCK
HOLD
VCC
Supply Voltage
* 25XX256 is used in this document as a generic part number for the 25AA256, 25LC256 devices.
2003 Microchip Technology Inc.
Preliminary
DS21822C-page 1