 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

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

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

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)

TSSOP

CS

SO

WP

1

2

3

4

8

7

6

5

HOLD

SCK

SI

(ST)

DFN

CS

SO

WP

HOLD

SCK

SI

5

6

7

8

4

3

2

1

(MF)

SPI is a registered trademark of Motorola Corporation.

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