32 Megabit (4M x 8-Bit) Flash Memory
29F0408
block information and create the invalid block table via the following suggested flow chart (Figure 1). Any intentional
erasure of the original block information is prohibited.
F
IGURE
1. F
LOW CHART TO CREATE INVALID BLOCK TABLE
Error in write or read operation
Over its lifetime, the additional invalid blocks may occur. Through the tight process control and intensive testing, addi-
tional block failure rate is minimized which is projected below 0.1% until 1 million program/erase cycles. Refer to the
qualification report for the actual data. The following possible failure modes should be considered to implement a
highly reliable system. In the case of status read failure after erase or program, block replacement should be done. To
improve the efficiency of memory space, it is recommended that the read or verification failure due to single bit error
be reclaimed by ECC without any block replacement. The said additional block failure rate does not include those
reclaimed blocks.
F
AILURE
M
ODE
Write
Erase failure
Program failure
D
ETECTION AND
C
OUNTERMEASURE
Status read after erase
Æ
Block replacement
Status read after program
Æ
Block replacement
Read back (verify after program)
Æ
Block replacement or
ECC correction
Verify ECC
Æ
ECC correction
Read
Single bit failure
ECC: Error Correcting Code
Æ
Hamming Code, etc.
Example. 1-bit correction and 2-bit detection
11.08.02 Rev 2
All data sheets are subject to change without notice
8
©2002 Maxwell Technologies
All rights reserved.
MAXWELL [ MAXWELL TECHNOLOGIES ]
