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The Am29F040B is a 5.0V, 4Mb FLASH memory device. However, the Am29F040B is obsolete and is not recommended for new designs.
The S29AL016J is a 3.0V, 16Mb FLASH memory device. The S29AL016J is active and is scheduled for production through 2022.
There is also the S29AL008J, which is a 3.0V, 8Mb FLASH memory device. The S29AL008J has one less adrs line than that of the S29AL016J. The S29AL008J is also active and is also scheduled for production through 2022, as well.
URL to S29AL008J datasheet :
The Command Definitions may be similar, if not identical. However, please check the individual datasheets for any
differences in regards to Command Definitions, as well as for timing parameters.
Hope this helps...