 2004 Microchip Technology Inc.

DS21223G-page 1

25AA640/25LC640

Device Selection Table

Features

• Low-power CMOS technology

- Write current: 3 mA typical

- Read current: 500

- Standby current: 500 nA typical

• 8192 x 8 bit organization

• 32 byte page

• Write cycle time: 5 ms max.

• Self-timed erase and write cycles

• 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

- Data retention: > 200 years

- ESD protection: > 4000V

• 8-pin PDIP, SOIC and TSSOP packages

• Temperature ranges supported:

- Industrial (I): -40

°C to +85°C

- Automotive (E): -40

°C to +125°C

Description

The Microchip Technology Inc. 25AA640/25LC640

PROM [EEPROM]. 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.

Block Diagram

Package Types

Part

Number

Range

Max Clock

Frequency

Temp

Ranges

25AA640

1.8-5.5V

1 MHz

I

25LC640

2.5-5.5V

2 MHz

I

25LC640

4.5-5.5V

3/2.5 MHz

I, E

SI

SO

SCK

CS

HOLD

WP

Status

Register

I/O Control

Memory

Control

Logic

HV Generator

EEPROM

Array

Page

Y Decoder

Sense Amp.

R/W Control

Logic

Latches

XDEC

PDIP/SOIC

TSSOP

CS

SO

WP

HOLD

SCK

SI

8

7

6

5

1

2

3

4

8

7

6

5

1

2

3

4

HOLD

CS

SO

SCK

SI

WP

*25XX640 is used in this document as a generic part number for the 25AA640/25LC640 devices.

SPI is a registered trademark of Motorola Corporation.