You are here

QDR-II | Cypress Semiconductor


Cypress’s QDR-II is a high performance, dual-port SRAM memory. QDR-II SRAM offers a maximum speed of 333 MHz, densities up to 144 Mb, read latencies of 1.5 or 2.5 cycles, burst length of 2 or 4, and is available in an industry-standard 165-ball FBGA package.

The QDR-II family also includes double data rate (DDR-II) devices. DDR-II devices are similar to QDR-II devices except that all DDR devices have a burst length of 2 and a single data rate address bus. Additionally, DDR-II is available in SIO (separate I/O) or CIO (common I/O) options. SIO devices provide independent read and write ports, eliminating the data bus “turnaround” time found in CIO devices. CIO devices provide a single port for reads and writes, reducing the number of required data pin connections.


Maximum Frequency 333 MHz
Maximum Random Transaction Rate 333 MT/s (Burst of 4)
667 MT/s (Burst of 2)
Density 18-144 Mb
Bus Width x18, x36
Burst Length 2, 4
Package FBGA165
Read Latency 1.5, 2.5 cycles
Core Voltage 1.8 V
I/O Voltage 1.5 V
  1. Download the DDR-II SRAM Design Guide
  2. Download the DDR-II Datasheets