ISO 7816 Compatible
64K
X76F641
Secure SerialFlash
DESCRIPTION
8Kx8+32x8
FEATURES
• 64-bit Password Security
—Five 64-bit Passwords for Read, Program
and Reset
• 8192 Byte+32 Byte Password Protected Arrays
—Seperate Read Passwords
—Seperate Write Passwords
—Reset Password
• Programmable Passwords
• Retry Counter Register
—Allows 8 tries before clearing of both arrays
—Password Protected Reset
• 32-bit Response to Reset (RST Input)
• 32 byte Sector Program
• 400kHz Clock Rate
• 2 wire Serial Interface
• Low Power CMOS
—2.0 to 5.5V operation
—Standby current Less than 1µA
—Active current less than 3 mA
• High Reliability Endurance:
—100,000 Write Cycles
• Data Retention: 100 years
• Available in:
—8 lead EIAJ SOIC
—SmartCard Module
The X76F641 is a Password Access Security Supervisor,
containing one 65536-bit Secure SerialFlash array and
one 256-bit Secure SerialFlash array. Access to each
memory array is controlled by five 64-bit passwords
each. These passwords protect read and write opera-
tions of the memory array. A separate RESET password
is used to reset the passwords and clear the memory
arrays in the event the read and write passwords are lost.
The X76F641 features a serial interface and software
protocol allowing operation on a popular two wire bus.
The bus signals are a clock Input (SCL) and a bidirec-
tional data input and output (SDA).
The X76F641 also features a synchronous response to
reset providing an automatic output of a hard-wired 32-bit
data stream conforming to the industry standard for
memory cards.
The X76F641 utilizes Xicor’s proprietary Direct Write
TM
cell, providing a minimum endurance of 100,000 cycles
and a minimum data retention of 100 years.
Functional Diagram
SCL
SDA
INTERFACE
LOGIC
DATA TRANSFER
ARRAY ACCESS
ENABLE
8K BYTE
SerialFlash ARRAY
ARRAY 0
(PASSWORD PROTECTED)
PASSWORD ARRAY
AND PASSWORD
VERIFICATION LOGIC
RST
RESET
RESPONSE REGISTER
32 BYTE
SerialFlash ARRAY
ARRAY 1
(PASSWORD PROTECTED)
RETRY COUNTER
7025 FM 01
©
Xicor, Inc. 1994, 1995, 1996 Patents Pending
9900-5004.5 3/9/99 EP
1
Characteristics subject to change without notice
XICOR [ XICOR INC. ]
