- overview, tutorial about the basics of what is DDR4 SDRAM, its technology operation, advantages & disadvantages.

DDR3 is the fourth generation of DDR SDRAM technology.

DDR4 SDRAM brings with it further improvements in overall performance which have ensured it has a significant benefit over the previous generation of SDRAM technology.

With the previous generations of SDRAM well established and widely sued, it was necessary to ensure that the future needs were met. As a result DDR4 SDRAM was developed and introduced.

DDR4 SDRAM basics

DDR4 SDRAM offers some distinct advantages over the previous generations of DDR SDRAM.

  • Data rates:   At the time DDR4 was introduced, it was anticipated that DDR3 would peak at a data rate of 1.6 Giga transfers per second per pin. Accordingly this was set as the entry point for DDR4 SDRAM. This transfer rate is expected to rise to twice this level, i.e. 3.2 Giga transfers per second, with possible increases on this.
  • Operating voltage:   A roadmap has been set up for the DDR4 SDRAM VDD supply voltage to remain at 1.2 volts and then over time be reduced as other technologies change. This will be achieved by keeping by holding VDDQ constant at 1.2V and the I/O voltage stable.
  • DQ bus:   . One of the other performance features planned for inclusion in the DDR4 SDRAM standard are a pseudo open drain interface on the DQ bus.
  • Data width:   DDR4 SDRAM offers three values of data width: x4, x8 and x16.
  • Prefetch:   DDR4 SDRAM architecture uses 8n prefetch with bank groups. This includes two or four selectable bank groups. This enables the DDR4 SDRAM to have separate activation, read, write or refresh operations underway in each of the unique bank groups. This techniques increases the memory bandwidth and efficiency. It is particularly suited for memory applications where small levels of granularity are required.
  • Differential signalling:   For DDR4 SDRAM the clock and strobe lines will utilise differential signalling.

By Ian Poole

<< Previous   |   Next >>

Share this page

Want more like this? Register for our newsletter

Clarifying Machine Vision with High Quality Sensors Mark Patrick | Mouser Electronics
Clarifying Machine Vision with High Quality Sensors
Automated imaging technology is everywhere we look. As cameras and their processing units get ever smaller, they are moving into ever more industries - from speed cameras and factory production lines to diagnostic medicine. For many of these applications, image quality is critical - but what does image quality really mean? Different applications will require quite distinct performance characteristics. Understanding camera specifications, differences between CCD and CMOS sensors, and features such as real-time processing or near-infrared (NIR) can help guide the camera selection process to produce better imaging results.

Radio-Electronics.com is operated and owned by Adrio Communications Ltd and edited by Ian Poole. All information is © Adrio Communications Ltd and may not be copied except for individual personal use. This includes copying material in whatever form into website pages. While every effort is made to ensure the accuracy of the information on Radio-Electronics.com, no liability is accepted for any consequences of using it. This site uses cookies. By using this site, these terms including the use of cookies are accepted. More explanation can be found in our Privacy Policy