© 2007 Microchip Technology Inc.

DS21822F-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: 6 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:

• Pb-Free and RoHS Compliant

Pin Function Table

Description:

The Microchip Technology Inc. 25AA256/25LC256

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 sep-

arate 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.

Package Types (not to scale)

Part Number

Page Size

Temp. Ranges

Packages

25LC256

2.5-5.5V

64 Byte

I, E

P, SN, SM, ST, MF

25AA256

1.8-5.5V

64 Byte

I

P, SN, SM, 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

Ground

SI

Serial Data Input

SCK

Serial Clock Input

HOLD

Hold Input

Supply Voltage

CS

SO

WP

1

2

3

4

8

7

6

5

HOLD

SCK

SI

PDIP/SOIC

(P, SN, SM)

TSSOP

(ST)

DFN

CS

SO

WP

HOLD

SCK

SI

5

6

7

8

4

3

2

1

(MF)

8

7

6

5

1

2

3

4

HOLD

CS

SO

SCK

SI

WP

Rotated TSSOP

(ST)

8

7

6

5

1

2

3

4

HOLD

CS

SO

SCK

SI

WP

256K SPI Bus Serial EEPROM

* 25XX256 is used in this document as a generic part number for the 25AA256, 25LC256 devices.