Infineon offers a comprehensive portfolio of Sync SRAMs including Standard Sync SRAM, NoBL™ SRAM, DDR/QDR SRAM.
Standard Sync SRAMs were created especially for cache applications. These devices incorporate an internal 2-bit burst counter that supports a cache line size of four. These are available in densities ranging from 2 Mbit to 72 Mbit.
No Bus Latency (NoBL™) Sync SRAMs: Commonly known as Zero bus Turn-around (ZBT) SRAMs, they require no idle cycles when the bus is turned around, that is, when it transitions from Read to Write, or Write to Read. Two versions of NoBL SRAM exist: Flow-through and Pipelined. NoBL Flow-through SRAMs always have a one clock cycle delay from address to data in the system. Pipelined NoBL SRAM requires an additional pipelined register in the device output. These are available in densities ranging from 2 Mbit to 144 Mbit.
DDR-II/II+/II+ Xtreme Sync SRAMs: DDR stands for Dual Data Rate. DDR-II SRAMs have common Read and Write ports. These are similar to the legacy Synchronous Burst SRAM products but with double data rate I/Os. They are suitable for read intensive functions such as packet look up and packet classification in networking/ communication applications.
QDR-II/II+/II+ Xtreme Sync SRAMs: QDR stands for Quad Data Rate. QDR-II SRAMs were developed to address network applications that require the low latency and full cycle utilization of NoBL SRAMs but also require a significantly higher operating frequency. QDR-II SRAMs have separate Read and Write buses. QDR SRAM memories are available in densities ranging from 18 Mbit to 144 Mbit
QDR-IV Sync SRAMs: The QDR-IV SRAMs are high-performance memory devices optimized to maximize the number of random transactions per second by the use of two independent bidirectional data ports. QDR SRAMs are used in networking applications where reads and writes are balanced such as packet buffer, statistics counters, flow state, and scheduling. They are available in 72 Mbit and 144 Mbit densities with the Random Transaction Rate (RTR) required for 100-400 Gigabit line cards in switches and routers
This application note will help you choose the right Synchronous SRAM for your application.