Functional Description
As a memory standard, the (Quad Data Rate) QDR-II SRAM interface has become increasingly common in high performance networking systems. With the QDR-II interface/configuration, memory throughput is increased without increasing the clock rate via the use of two unidirectional buses on each of providing 2 ports of QDR-II makes this a Dual-QDRII Static Ram two ports to transfer data without the need for bus turnaround.

Features
◆ 18Mb Density (512K x 36)
   – Also available 9Mb Density (256K x 36)
◆ QDR-II x 36 Burst-of-2 Interface
   – Commercial: 233MHz, 250MHz
◆ Two independent ports
   – True Dual-Port Access to common memory
◆ Separate, Independent Read and Write Data Buses on each Port
   – Supports concurrent transactions
◆ Two-Word Burst on all DPRAM accesses
◆ DDR (Double Data Rate) Multiplexed Address Bus
   – One Read and One Write request per clock cycle
◆ DDR (Double Data Rate) Data Buses
   – Four word burst data (Two Read and Two Write) per clock on each port
   – Four word transfers each of Read & Write per clock cycle per port (four word bursts on 2 ports)
◆ Octal Data Rate
◆ Port Enable pins (E0,E1) for depth expansion
◆ Dual Echo Clock Output with DLL-based phase alignment
◆ High Speed Transceiver Logic inputs
   – scaled to receive signals from 1.4V to 1.9V
◆ Scalable output drivers
   – Drives HSTL, 1.8V TTL or any voltage level from 1.4V to 1.9V
   – Output impedance adjustable from 35 ohms to 70 ohms
◆ 1.8V Core Voltage (VDD)
◆ 576-ball Flip Chip BGA (25mm x 25mm, 1.0mm ball pitch)
◆ JTAG Interface - IEEE 1149.1 Compliant