ATO25F1GC-30EC datasheet(35/46 Pages) ETC

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Sep.2013. Rev 0.5

1Gbit Serial NAND Flash Memory

Error Management

This NAND Flash device is specified to have the minimum number of valid blocks (NVB) of the

total available blocks per die shown in the table below. This means the devices may have blocks

that are invalid when shipped from the factory. An invalid block is one that contains at least one

page that has more bad bits than can be corrected by the minimum required ECC. Additional bad

blocks may develop with use. However, the total number of available blocks will not fall below NVB

during the endurance life of the product.

Although NAND Flash memory devices may contain bad blocks, they can be used reliably in

systems that provide bad-block management and error-correction algorithms. This ensures data

integrity. Internal circuitry isolates each block from other blocks, so the presence of a bad block

does not affect the operation of the rest of the NAND Flash array.

NAND Flash devices are shipped from the factory erased. The factory identifies invalid blocks

before shipping by attempting to program the bad-block mark into every location in the first page of

each invalid block. It may not be possible to program every location in an invalid block with the

bad-block mark. However, the first spare area location in each bad block is guaranteed to contain

the bad-block mark. See the following table for the bad-block mark.

System software should initially check the first spare area location for non-FFh data on the first

page of each block prior to performing any program or erase operations on the NAND Flash device.

A bad-block table can then be created, enabling system software to map around these areas.

Factory testing is performed under worst-case conditions. Because invalid blocks may be marginal,

it may not be possible to recover the bad-block marking if the block is erased. The 1st block, which

is placed on 00h block address, is guaranteed to be a valid block up to 1K program/erase cycles.

Table 6. Error Management Details

Description

Requirement

Minimum number of valid blocks (Nvb)

1004

Total available blocks per die

1024

First spare area location

Byte 2048

Bad block mark

00h

ATO25F1GC-30EC Datasheet(PDF) 35 Page - List of Unclassifed Manufacturers