DESCRIPTION
The X76F640 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 two 64-bit passwords. These passwords protect read and write operations 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 X76F640 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). Access to the device is controlled through a chip select (CS) input, allowing any number of devices to share the same bus.
The X76F640 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 X76F640 utilizes Xicor’s proprietary Direct WriteTM cell, providing a minimum endurance of 100,000 cycles and a minimum data retention of 100 years.

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
   —2.7 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 SOIC
   —SmartCard Module