MBM30LV0128 Fujitsu Microelectronics, Inc., MBM30LV0128 Datasheet - Page 35

• Manufacturer Part Number: MBM30LV0128
• Description: Flash Memory 128 M 16 M X 8 Bit Nand-type
• Manufacturer: Fujitsu Microelectronics, Inc.

* : (1) or (2)
Erase
(12) Invalid block (bad block)
(13) Failure Phenomena for Program and Erase Operations
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, detection methods
and remedies are listed in the following table. System-based remedies will provide a highly reliable system.
• ECC
• Block Replacement
If an error occurs at erasing, like programming, remedies should be executed on a system basis to prevent
access to blocks causing the error.
Memory
Buffer
Program
Failure Mode
Erase Failure
Program Failure
Program Failure
“1”
error occurs
: Error Correcting code
Example : 1 bit correction & 2 bit detection.
“0”
Bad Block
Bad Block
Figure 35 Reprogramming to Good Block
Some MBM30LV0128 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 Bad Block
Status Read after Erase
Status Read after Prog.
(1) Block Verify after Prog.
(2) ECC
Figure 36. Shows the Bad Block Test Flow
Block A
Block B
Hamming Code etc.
Detection and Countermeasure Sequence
If an error occurs in block A, reprogramming from
the external buffer to block B is recommended.
Block A should not be accessed after an error
occurs.
1014
Min.
Block Replacement
Block Replacement
Retry
1024
Max.
MBM30LV0128
Block
Unit
35