A
PPLICATION
N
OTES
A V A I L A B L E
AN19
X25640
• AN38 • AN41 • AN61
64K
X25640
DESCRIPTION
8K x 8 Bit
Advanced SPI Serial E
2
PROM With Block Lock
TM
Protection
FEATURES
•
•
•
•
•
•
•
•
•
•
•
1MHz Clock Rate
Low Power CMOS
—200
µ
A Standby Current
—5mA Active Current
5 Volt Power Supply
SPI Modes (0,0 & 1,1)
8K X 8 Bits
—32 Byte Page Mode
Block Lock Protection
—Protect 1/4, 1/2 or all of E
2
PROM Array
Built-in Inadvertent Write Protection
—Power-Up/Power-Down protection circuitry
—Write Enable Latch
—Write Protect Pin
Self-Timed Write Cycle
—5ms Write Cycle Time (Typical)
High Reliability
—Endurance: 100,000 cycles
—Data Retention: 100 Years
—ESD protection: 2000V on all pins
8-Lead PDlP Package
14-Lead SOIC Package
The X25640 is a CMOS 65,536-bit serial E
2
PROM,
internally organized as 8K x 8. The X25640 features a
Serial Peripheral Interface (SPI) and software protocol
allowing 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 X25640 also features two additional inputs that
provide the end user with added flexibility. By asserting
the
HOLD
input, the X25640 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 X25640 disabling all write attempts to the status
register, thus providing a mechanism for limiting end
user capability of altering 0, 1/4, 1/2 or all of the memory.
The X25640 utilizes Xicor’s proprietary Direct Write™
cell, providing a minimum endurance of 100,000 cycles
and a minimum data retention of 100 years.
FUNCTIONAL DIAGRAM
STATUS
REGISTER
WRITE
PROTECT
LOGIC
X DECODE
LOGIC
64
64 X 256
SO
SI
SCK
CS
HOLD
COMMAND
DECODE
AND
CONTROL
LOGIC
64
64 X 256
8K BYTE
ARRAY
128
128 X 256
WP
WRITE
CONTROL
AND
TIMING
LOGIC
32
8
Y DECODE
DATA REGISTER
3089 ILL F01
Direct Write™ and Block Lock™ Protection is a trademark of Xicor, Inc.
©Xicor, Inc. 1994, 1995, 1996 Patents Pending
3089-1.8 6/17/96 T4/C4/D1 NS
1
Characteristics subject to change without notice
XICOR [ XICOR INC. ]
