15 ns access time — timing margin for legacy buses
The CY7C1399BN-15VXCT: The 15 ns access time matches the timing requirements of many 33 MHz bus controllers and DSPs that expect a 20 ns or faster memory cycle. At 3.3 V nominal, the part delivers address-to-data valid within 15 ns, leaving margin for board trace delays and capacitive loading. For a 50 MHz controller, the 15 ns window may be tight; a faster 10 ns or 12 ns SRAM would be a safer choice.
Package and supply rail considerations
The 28-SOJ package (0.300 inch body width, 7.62 mm) is a JEDEC-standard footprint shared by many 256Kbit and 1Mbit asynchronous SRAMs. It is not 5 V tolerant on the I/O pins; level translation is required if interfacing with a 5 V logic family.