AT25DF641_13 datasheet(2/56 Pages) ETC2

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AT25DF641

3680F–DFLASH–4/10

Description

The AT25DF641 is a s erial interface Flash memory device designed for use in a w ide variety of high-volume

consumer based applications in which program code is shadowed from Flash memory into embedded or external

RAM for execution. The flexible erase architecture of the AT25DF641, with its erase granularity as small as 4-

Kbytes, makes it ideal for data storage as well, eliminating the need for additional data storage EEPROM devices.

The physical sectoring and the erase block sizes of the AT25DF641 have been optimized to meet the needs of

today's code and data storage applications. By optimizing the size of the physical sectors and erase blocks, the

memory space can be used much more efficiently. Because certain code modules and data storage segments

must reside by themselves in their own protected sectors, the wasted and unused memory space that occurs with

large sectored and large block erase Flash memory devices can be greatly reduced. This increased memory

space efficiency allows additional code routines and data storage segments to be added while still maintaining the

same overall device density.

The AT25DF641 also offers a sophisticated method for protecting individual sectors against erroneous or

malicious program and erase operations. By providing the ability to individually protect and unprotect sectors, a

system can unprotect a specific sector to modify its contents while keeping the remaining sectors of the memory

array securely protected. This is useful in applications where program code is patched or updated on a subroutine

or module basis or in applications where data storage segments need to be modified without running the risk of

errant modifications to the program code segments. In addition to individual sector protection capabilities, the

AT25DF641 incorporates Global Protect and Global Unprotect features that allow the entire memory array to be

either protected or unprotected all at once. This reduces overhead during the manufacturing process since

sectors do not have to be unprotected one-by-one prior to initial programming.

To take code and data protection to the next level, the AT25DF641 incorporates a sector lockdown mechanism

that allows any combination of individual 64-Kbyte sectors to be locked down and become permanently read-only.

This addresses the need of certain secure applications that require portions of the Flash memory array to be

permanently protected against malicious attempts at altering program code, data modules, security information, or

encryption/decryption algorithms, keys, and routines. The device also contains a s pecialized OTP (One-Time

Programmable) Security Register that can be used for purposes such as unique device serialization, system-level

Electronic Serial Number (ESN) storage, locked key storage, etc.

Specifically designed for use in 3-volt systems, the AT25DF641 supports read, program, and erase operations

with a supply voltage range of 2.7V to 3.6V. No separate voltage is required for programming and erasing.

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