MBM30LV0032 Fujitsu Microelectronics, Inc., MBM30LV0032 Datasheet - Page 34

• Manufacturer Part Number: MBM30LV0032
• Description: 32m 4m X 8 Bit Nand-type
• Manufacturer: Fujitsu Microelectronics, Inc.

34
MBM30LV0032
(12) Invalid block (bad block)
(13) Failure Phenomena for Program and Erase Operations
Erase
Block
Page
Single Bit*
The device contains unusable blocks. Therefore, the following issues must be recognized:
Repeated rewriting might cause an error at programming and erasing. Possible error modes, and detection
methods and remedies are listed in the following table. System-based remedies will provide a highly reliable
system.
* : (1) or (2)
If an error occurs at erasing, like programming, remedies should be executed on a system basis to prevent
access to blocks causing the error.
ECC
Block Replacement
Memory
Buffer
Program
:
Failure Mode
Error Correcting code
Example : 1 bit correction & 2 bit detection.
error occurs
Erase Failure
Program Failure
Program Failure
‘1’
‘0’
Bad Block
Bad Block
Figure 35
Hamming Code etc.
Some MBM30LV0032 products have invalid blocks (bad blocks) at
shipping. After mounting the device in the system, test whether
there are no bad blocks. If there are any bad blocks, they should
not be accessed.
The bad blocks are connected to sense-amp of the bit lines via the
selector transistors. Good blocks will not be affected unless the bad
blocks are accessed. The effective number of good blocks
specified by Fujitsu is shown below.
Valid (Good) Block Number
Figure 34
Status Read after Erase
Status Read after Prog.
(1) Block Verify after Prog.
(2) ECC
Reprogramming to Good Block
Block A
Block B
Figure 36. Shows the Bad Block Test Flow
Detection and Countermeasure Sequence
Bad Block
If an error occurs in block A, reprogramming from
the external buffer to block B. Block A should not
be accessed after an error occurs.
Min.
502
Block Replacement
Block Replacement
Retry
Typ.
Max.
512
Block
Unit