18 Mbit DDR II+ SRAM — 300 MHz pipeline for the line card
The Cypress CY7C1318JV18-300BZC is an 18 Mbit synchronous SRAM organised as 1M x 18, built on the DDR II+ (Double Data Rate, second generation) architecture. It clocks at 300 MHz, transferring data on both edges for an effective 600 MT/s bandwidth through a parallel interface. It comes in a 165-ball FBGA (13x15 mm) footprint — a fine-pitch BGA that demands careful PCB layout and a controlled reflow profile.
This part is officially marked Obsolete by Cypress (now Infineon). For production or repair, the only channel is the surplus and broker market.
The 300 MHz clock rate with double-data-rate signalling means the bus delivers 600 million transfers per second. For a 1M x 18 organisation, that translates to a peak bandwidth of 10.8 Gbit/s (18 bits × 600 MT/s). This level of throughput suits high-performance networking equipment — switches, routers, and line cards — where the SRAM serves as a look-up table or packet buffer. The DDR II architecture reduces the number of dead cycles on the bus compared to standard synchronous SRAM, but it still requires a dedicated controller that can handle the DDR timing (data strobe, write preamble, echo clock).
165-FBGA — layout and rework notes
The 165-ball FBGA (13x15 mm) is a fine-pitch BGA. That means the PCB requires via-in-pad or microvia fanout for the inner rows. The package is moisture-sensitive — assume MSL 3 unless the bag label says otherwise; bake before reflow if the floor-life window has been exceeded. For rework, a bottom-side preheat profile that keeps the top-side below 200°C is recommended to avoid internal delamination.