2Mx16, 55ns — what the speed grade means on the bench
The R1LV3216RSD-5SR#B0 is a 2Mx16 standard SRAM from Renesas Electronics, with a 55ns access time. That 55ns figure is the chip-enable-to-data-valid window — the processor or DMA controller must hold the address stable for at least that long before the data bus is guaranteed to carry the read word. For a 16-bit microcontroller running at 20 MHz (50 ns cycle), this SRAM will insert one wait state on a back-to-back read; a 10 MHz bus (100 ns cycle) reads it in zero wait states.
Bulk package and board-fit note
Supplied in Bulk — loose units in an anti-static tube or tray, not tape-and-reel. For prototype builds or low-volume production this is fine; for high-volume pick-and-place you will want to confirm the tube-to-feeder adapter or request reel packaging separately. The package itself is a standard TSOP or BGA footprint typical of Renesas low-power SRAMs — check the mechanical drawing for pin-1 orientation before laying out the board.