APPLICATION
NOTE
A V A I L A B L E
AN19 • AN38 • AN41 • AN61
64K
8K x 8 Bit
X25642
2
TM
Advanced SPI Serial E PROM with Block Lock Protection
FEATURES
DESCRIPTION
• 2MHz Clock Rate
The X25642 is a CMOS 65,536-bit serial E2PROM,
internally organized as 8K x 8. The X25642 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
controlled through a chip select (CS) input, allowing
any number of devices to share the same bus.
• Low Power CMOS
—<1µA Standby Current
—<5mA Active Current
• 2.7V To 5.5V 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 E2PROM Array
• Built-in Inadvertent Write Protection
—Power-Up/Down protection circuitry
—Write Enable Latch
—Write Protect Pin
• Self-Timed Write Cycle
—5ms Write Cycle Time (Typical)
• High Reliability
The X25642 also features two additional inputs that
provide the end user with added flexibility. By
asserting the HOLD input, the X25642 will ignore tran-
sitions on its inputs, thus allowing the host to service
higher priority interrupts. The WP input can be used as
a hardwire input to the X25642 disabling all write
attempts to the status register, thus providing a mech-
anism for limiting end user capability of altering 0, 1/4,
1/2 or all of the memory.
—Endurance: 100,000 cycles
—Data Retention: 100 Years
—ESD protection: 2000V on all pins
• Packages
The X25642 utilizes Xicor’s proprietary Direct WriteTM
cell, providing a minimum endurance of 100,000
cycles and a minimum data retention of 100 years.
—8-Lead PDIP
—8-Lead SOIC
—14-Lead SOIC
—20-Lead TSSOP
FUNCTIONAL DIAGRAM
WRITE
PROTECT
LOGIC
STATUS
REGISTER
X DECODE
LOGIC
8K BYTE
ARRAY
64
64
64 X 256
64 X 256
SO
COMMAND
DECODE
AND
CONTROL
LOGIC
SI
SCK
CS
HOLD
128
128 X 256
WRITE
CONTROL
AND
TIMING
LOGIC
WP
32
8
Y DECODE
DATA REGISTER
3132 ILL F01.1
Direct Write and Block Lock Protection is a trademark of Xicor, Inc.
Xicor, Inc. 1994, 1995, 1996 Patents Pending
3132-1.0 1/17/97 T5/C0/D1 SH
1
Characteristics subject to change without notice