X25021

1

2K

X25021

256 x 8 Bit

©Xicor, Inc. 1995, 1996 Patents Pending

Characteristics subject to change without notice

6615-1.5 6/10/96 T3/C1/D0 NS

Direct Write™ and Block Lock™ Protection is a trademark of Xicor, Inc.

FEATURES

—4 Byte Page Mode

—10

—3mA Active Current

—Power-Up/Power-Down protection circuitry

—Write Latch

—Write Protect Pin

—5ms Write Cycle Time (Typical)

—Endurance: 100,000 cycles per byte

—Data Retention: 100 Years

—ESD protection: 2000V on all pins

DESCRIPTION

nally organized as 256 x 8. The X25021 features a Serial

Peripheral Interface (SPI) and software protocol allow-

ing operation on a simple three-wire bus. The bus

signals are a clock input (SCK) plus separate data in (SI)

and data out (SO) lines. Access to the device is con-

trolled through a chip select (

CS) input, allowing any

number of devices to share the same bus.

The X25021 also features two additional inputs that

provide the end user with added flexibility. By asserting

the

HOLD input, the X25021 will ignore transitions on its

inputs, thus allowing the host to service higher priority

interrupts. The

WP input can be used as a hardwire input

to the X25021 disabling all write attempts, thus providing

a mechanism for limiting end user capability of altering

the memory.

The X25021 utilizes Xicor’s proprietary Direct Write™

cell, providing a minimum endurance of 100,000 cycles

per byte and a minimum data retention of 100 years.

6615 FHD F01

FUNCTIONAL DIAGRAM

COMMAND

DECODE

AND

CONTROL

LOGIC

WRITE

CONTROL

AND

TIMING

LOGIC

WRITE

PROTECT

LOGIC

X DECODE

LOGIC

256 BYTE

ARRAY

16 X 32

Y DECODE

DATA REGISTER

16 X 32

32 X 32

SO

SI

SCK

CS

HOLD

WP

16

16

32

8

4

STATUS

REGISTER