The Infineon CY7C4255-10AC is a synchronous FIFO memory from the CY7C series, organized as 8K x 18 bits for a total of 144K bits. It clocks at 100 MHz with an 8 ns access time, operating from a 4.5 V to 5.5 V supply.
100 MHz clock, 8 ns access — timing margin for the bus
The 100 MHz data rate and 8 ns access time set the read-cycle timing window.
144K (8K x 18) depth — buffer sizing for packet or line-rate storage
With 8K entries of 18 bits each, this FIFO holds 144K bits.
Sourcing reality — obsolete, sourced to order
The CY7C4255-10AC is marked obsolete. No official successor is listed in the evidence.