250 MHz QDR II SRAM — what the clock rate buys you
The 250 MHz clock drives four data transfers per cycle — two reads and two writes — giving an effective 1 Gbps per pin bandwidth on the 18-bit bus. That throughput suits high-bandwidth buffer applications like network line cards, test equipment, and baseband processing where the memory must keep up with a streaming data path without inserting wait states.
The supply range of 1.7V to 1.9V places this part in the 1.8V nominal logic family. The VDD and VDDQ rails are separate on QDR II parts.
The 165-ball FBGA package (13x15 mm) is a standard BGA footprint with 1.0 mm ball pitch — route the outer rows on the top layer, use microvias for the inner rows to keep the signal integrity clean at 250 MHz.
Cypress lists the CY7C1312CV18-250BZI as obsolete. That means no factory orders, no last-time-buy window — the only channel is independent distribution and surplus inventory.