 2003 Microchip Technology Inc. Preliminary DS21822C-page 1
25AA256/25LC256
Device Selection Table
Features
• Max. clock 10 MHz
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.)
Block write protection
- Protect none, 1/4, 1/2 or all of array
Built-in write protection
- Power-on/off data protection circuitry
- Write enable latch
- Write-protect pin
Sequential read
High reliability
- Endurance: 1,000,000 erase/write cycles
- Data retention: > 200 years
- ESD protection: > 4000V
Temperature ranges supported;
Standard and Pb-free packages available
Pin Function Table
Description
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.
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.
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.
Package Types (not to scale)
Part Number VCC Range Page Size Temp. Ranges Packages
25LC256 2.5-5.5V 64 Byte I, E P, SN, ST, MF
25AA256 1.8-5.5V 64 Byte I P, SN, ST, MF
- Industrial (I): -40°Cto +85°C
- Automotive (E): -40°C to +125°C
Name Function
CS Chip Select Input
SO Serial Data Output
WP Write-Protect
VSS Ground
SI Serial Data Input
SCK Serial Clock Input
HOLD Hold Input
VCC Supply Voltage
25L
C256
CS
SO
WP
VSS
1
2
3
4
8
7
6
5
VCC
HOLD
SCK
SI
PDIP/SOIC
(P, SN)
TSSOP
CS
SO
WP
VSS
1
2
3
4
8
7
6
5
VCC
HOLD
SCK
SI
(ST)
DFN
CS
SO
WP
VSS
HOLD
SCK
SI
25
LC
2
5
6
5
6
7
8
4
3
2
1 VCC
(MF)
256K SPI
™
Bus Serial EEPROM
SPI is a registered trademark of Motorola Corporation.
* 25XX256 is used in this document as a generic part number for the 25AA256, 25LC256 devices.