AT25DF321A datasheet(2/53 Pages) ETC2

2 / 53 page

3686F–DFLASH–1/2014

AT25DF321A

Description

The AT25DF321A is a serial interface Flash memory device designed for use in a wide 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 AT25DF321A, 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 AT25DF321A 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 AT25DF321A 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 AT25DF321A 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 AT25DF321A 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 specialized 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 3V systems, the AT25DF321A 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.

AT25DF321A датащи(PDF) 2 Page - List of Unclassifed Manufacturers