9900-5004.5 3/9/99 EP
Xicor, Inc. 1994, 1995, 1996 Patents Pending
1
Characteristics subject to change without notice
64K
X76F641
8Kx8+32x8
Functional Diagram
Secure SerialFlash
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
DESCRIPTION
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
cell, providing a minimum endurance of 100,000 cycles
and a minimum data retention of 100 years.
TM
LOGIC
SCL
SDA
RST
INTERFACE
8K BYTE
SerialFlash ARRAY
ARRAY 0
(PASSWORD PROTECTED)
DATA TRANSFER
ARRAY ACCESS
ENABLE
RESET
RESPONSE REGISTER
PASSWORD ARRAY
AND PASSWORD
VERIFICATION LOGIC
RETRY COUNTER
32 BYTE
SerialFlash ARRAY
ARRAY 1
(PASSWORD PROTECTED)
7025 FM 01
ISO 7816 Compatible