333 MHz QDR II — what the clock buys
The Cypress CY7C1513KV18-333BZI is a 72 Mbit Synchronous QDR II SRAM organized 4M × 18, clocked at 333 MHz. QDR II (Quad Data Rate) architecture delivers two read and two write data words per clock cycle, giving an effective data rate of 666 MHz per I/O pin. For a 18-bit-wide bus, that translates to roughly 12 Gbps of aggregate bandwidth — the kind of throughput a network line card or high-end test instrument needs for packet buffer or acquisition memory.
The 1.8 V core supply demands tight decoupling: a 100 nF per power ball plus a bulk 10 µF within 5 mm of the package is the usual starting point.
Cypress lists the CY7C1513KV18-333BZI as Obsolete. For a BOM line that still calls out this exact density and speed grade, the sourcing path runs through independent distribution — last-time-buy inventory or verified surplus. The 333 MHz speed bin is the most common in the KV18 family, so stock does surface periodically, but it is not a part you can blanket-order from franchised channels.
Memory organization and bus width
Organized as 4M words × 18 bits. The 18-bit width is typical for designs that carry parity or ECC alongside 16-bit data — common in telecom frame processors and test equipment. The 4M depth gives 4 M entries per address, enough for moderate-depth packet buffers or trace capture. If the application needs deeper memory, the QDR II family scales to 144 Mbit in the same footprint; if narrower width suffices, the ×9 variants save pins.