X25021
2K
X25021
256 x 8 Bit
SPI Serial E2PROM with Block LockTM Protection
FEATURES
DESCRIPTION
The X25021 is a CMOS 2048-bit serial E2PROM, inter-
nallyorganizedas256x8. TheX25021featuresaSerial
Peripheral Interface (SPI) and software protocol allow-
ing operation on a simple three-wire bus. The bus
signalsareaclockinput(SCK)plusseparatedatain(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.
• 1MHz Clock Rate
• SPI Modes (0,1 & 1,0)
• 256 X 8 Bits
—4 Byte Page Mode
• Low Power CMOS
—10µA Standby Current
—3mA Active Current
• 2.7V To 5.5V Power Supply
• Block Lock Protection
—Protect 1/4, 1/2 or all of E2PROM Array
• Built-in Inadvertent Write Protection
—Power-Up/Power-Down protection circuitry
—Write Latch
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.TheWPinputcanbeusedasahardwireinput
totheX25021disablingallwriteattempts,thusproviding
a mechanism for limiting end user capability of altering
the memory.
—Write Protect Pin
• Self-Timed Write Cycle
—5ms Write Cycle Time (Typical)
• High Reliability
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.
—Endurance: 100,000 cycles per byte
—Data Retention: 100 Years
—ESD protection: 2000V on all pins
• 8-Lead PDlP Package
• 8-Lead SOIC Package
FUNCTIONAL DIAGRAM
WRITE
PROTECT
LOGIC
STATUS
REGISTER
X DECODE
LOGIC
256 BYTE
ARRAY
16
16
32
16 X 32
16 X 32
32 X 32
SO
SI
COMMAND
DECODE
AND
CONTROL
LOGIC
SCK
CS
HOLD
WRITE
CONTROL
AND
TIMING
LOGIC
WP
4
8
Y DECODE
DATA REGISTER
6615 FHD F01
Characteristics subject to change without notice
Direct Write™ and Block Lock™ Protection is a trademark of Xicor, Inc.
©Xicor, Inc. 1995, 1996 Patents Pending
6615-1.5 6/10/96 T3/C1/D0 NS
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