What this ZBT SRAM brings to the bus
The Renesas 71V2556S100PFG is a 4.5 Mbit synchronous SRAM organized 128K x 36, built on Zero Bus Turnaround (ZBT) technology. The 5 ns access time and 100 MHz clock rate support back-to-back reads and writes without dead cycles.
Package and environment
Housed in a 100-TQFP (14x14 mm), surface mount. Not rated for the factory floor or under-hood use. The 100-pin footprint is common enough that layout guides are easy to find, but verify the pinout against your controller's memory controller; the ZBT interface is standardized but some vendors swap byte-lane enables.
Lifecycle status is Active. No end-of-life notice, no last-time-buy pressure. This part is current production and available through the independent distribution channel. If you need a second-source option, the ZBT SRAM market has pin-compatible parts from other vendors at the same density and speed grade — check the package and timing specs against your controller's memory map before swapping.