HY27SA081G1M HYNIX [Hynix Semiconductor], HY27SA081G1M Datasheet - Page 23

• Manufacturer Part Number: HY27SA081G1M
• Description: 1Gbit (128Mx8bit / 64Mx16bit) NAND Flash Memory
• Manufacturer: HYNIX [Hynix Semiconductor]

Bad Block Management
Devices with Bad Blocks have the same quality level and the same AC and DC characteristics as devices where all the
blocks are valid. A Bad Block does not affect the performance of valid blocks because it is isolated from the bit line and
common source line by a select transistor.
The devices are supplied with all the locations inside valid blocks erased (FFh). The Bad Block Information is written
prior to shipping. Any block where the 6th Byte/ 1st Word in the spare area of the 1st or 2nd page (if the 1st page is
Bad) does not contain FFh is a Bad Block.
The Bad Block Information must be read before any erase is attempted as the Bad Block Information may be erased.
For the system to be able to recognize the Bad Blocks based on the original information it is recommended to create a
Bad Block table following the flowchart shown in Figure 20.
Block Replacement
Over the lifetime of the device additional Bad Blocks may develop. In this case the block has to be replaced by copying
the data to a valid block.
These additional Bad Blocks can be identified as attempts to program or erase them will give errors in the Status Reg-
ister.
As the failure of a page program operation does not affect the data in other pages in the same block, the block can be
replaced by re-programming the current data and copying the rest of the replaced block to an available valid block.
The Copy Back Program command can be used to copy the data to a valid block.
See the “Copy Back Program” section for more details.
Refer to Table 7 for the recommended procedure to follow if an error occurs during an operation.
Table 7: Block Failure
Rev 0.5 / Oct. 2004
Vccth(1)
Note: (1). V
CLE
ALE
Vcc
WE
I/O
CE
RB
(Read Busy time)
CCth
Figure 19. Automatic Page 0 Read at power-up (Sequential Row Read Enable)
is equal to 2.5V for 3V Power Supply devices.
tBLBH1
Operation
Program
Erase
Read
Busy
Data Out
Page 0
tBLBH1
1Gbit (128Mx8bit / 64Mx16bit) NAND Flash
Busy
Data Out
Page 1
tBLBH1
Recommended Procedure
Busy
Block Replacement or ECC
HY27UA(08/16)1G1M Series
HY27SA(08/16)1G1M Series
Block Replacement
Data Out
Page 2
ECC
tBLBH1
Busy
Page Nth
Data Out
23