NAND512R3A2CZA6E Micron Technology Inc, NAND512R3A2CZA6E Datasheet - Page 30

• Manufacturer Part Number: NAND512R3A2CZA6E
• Manufacturer: Micron Technology Inc

Specifications of NAND512R3A2CZA6E

• Cell Type: NAND
• Density: 512Mb
• Access Time (max): 15us
• Interface Type: Parallel
• Address Bus: 26b
• Operating Supply Voltage (typ): 1.8V
• Operating Temp Range: -40C to 85C
• Package Type: VFBGA
• Sync/async: Asynchronous
• Operating Temperature Classification: Industrial
• Operating Supply Voltage (min): 1.7V
• Operating Supply Voltage (max): 1.95V
• Word Size: 8b
• Number Of Words: 64M
• Supply Current: 15mA
• Mounting: Surface Mount
• Pin Count: 63
• Lead Free Status / Rohs Status: Compliant

Software algorithms
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Software algorithms
This section gives information on the software algorithms that Numonyx recommends to
implement to manage the bad blocks and extend the lifetime of the NAND device.
NAND flash memories are programmed and erased by Fowler-Nordheim tunneling using a
high voltage. Exposing the device to a high voltage for extended periods can cause the
oxide layer to be damaged. For this reason, the number of program and erase cycles is
limited (see
and it is recommended to implement garbage collection, a wear-leveling algorithm and an
error correction code, to extend the number of program and erase cycles and increase the
data retention.
To help integrate a NAND memory into an application Numonyx can provide a full range of
software solutions: file system, sector management, drivers, and code management.
Contact the nearest Numonyx sales office or visit www.numonyx.com for more details.
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 (x8 device)/1st
word (x16 device) in the spare area of the 1st page 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
NAND flash memory failure modes
Over the lifetime of the device additional bad blocks may develop.
To implement a highly reliable system, all the possible failure modes must be considered:
Refer to
Program/erase failure: 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 register.
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
program
Read failure: in this case, ECC correction must be implemented. To efficiently use the
memory space, it is mandatory to recover single-bit errors, which occur during read
operations, by using ECC without replacing the whole block.
Table 13
Figure
Table 14: Program, erase times and program erase endurance cycles
for more details
16.
for the procedure to follow if an error occurs during an operation.
Section 6.4: Copy back
NAND512-A2C
for value)