The FLEx72 Dual Port RAM (CYD18S72V) is an 18Mb Dual Port with a 256Kx72 configuration The FLEx72-E (CYD18S72V18) Dual Port RAM is also an 18Mb Dual Port device with additional features and will be offered mid-2004.
The FLEx72 device is a 3.3V device with an LVTTL I/O standard. The FLEx72-E is a drop in replacement for the FLEx72 device. Outlined in the current CYD18S72V datasheet are connections for the balls that represent the additional features in the FLEx72-E Dual Port RAM. These connections essentially disable the additional features. If the CYD18S72V device meets the needs for your system, no changes need to be made for the FLEx72-E to be a drop in replacement.
If you would like to take advantage of the additional features in the FLEx72-E Dual Port RAM, there is an application note titled "Migration from the FLEx72TM 18Mb Dual Port to the FLEx72-ETM 18Mb Dual Port RAM" to explain the features and how to implement them. Please contact Cypress sales for more information.