Mobile DRAM

As the world leader and one of the largest suppliers of advanced memory technology,
Samsung provides memory solutions for the next-generation of mobile devices.

Just as processors (CPUs) in standard desktop and laptop computers require DRAM memory for their operation, processors in handheld devices, such as mobile phones, also require memory to operate.

However, the key difference between memory types used in these devices is power consumption. Whereas desktop computers may have sufficient power to operate (via power lines), handheld devices must usually run on batteries and at the same time, offer sufficient durations of usage to users. As such, there is an immediate need for mobile memory that consumes significantly less power while still providing the same functionality so that it can be used in power-constrained handheld devices. Mobile DRAM was developed to fulfill this need.

Mobile DRAM is a version of the standard DRAM memory that has been redesigned specifically for use in handheld, battery-powered devices, such as mobile phones, PDAs, MP3s, PMPs, and tablet PCs, with the primary objective of reducing power consumption and extending the device's battery life. Mobile DRAM is also known as Low Power DDR (LPDDR) RAM.

Over the years, with advances in semiconductor and memory technologies, Mobile DRAM has exhibited significant improvements in density, operating speed, and power consumption, and has officially undergone several revisions (LPDDR2 and LPDDR3) over the original LPDDR (LPDDR1) standard. In general, an improvement in these three primary parameters of any generation's memory technology makes possible the production of memory chips with higher capacities being capable of operating at higher speeds and consuming less power ultimately widening their deployment and usability areas.

While the original DDR SDRAM operates at 2.5V, Mobile DRAM operates from voltages as low as 1.8V to 1.2V (based on the version), significantly reducing power consumption for the device that it is deployed in. Along with reduced power consumption, Mobile DRAM also offers the added benefits of higher densities and operating speeds, resulting in faster data transfers (up to 1,600Mbps for LPDDR3).

The growth in the development of Mobile DRAM technology has mainly been driven by the growth in the usage and adoption of smartphones and their content. Data for the last ten years (illustrated in the graph below) show consistent year-wise growth in the memory capacities of smartphones.

As smartphones become more powerful, functional, and capable, they need increasing amounts of both types of memory - DRAM as well as NAND.

2010 marked the first time that the combined sales of all mobile devices, such as smartphones and tablet PCs, which are the primary business areas for Mobile DRAM, exceeded the combined sales of traditional computing devices such as laptop and desktop PCs.

Projections and forecasts for the sales and adoption of mobile devices for the next five years are promising, and with additional opportunities to tap into and develop Mobile DRAM technology, even more so.

Bandwidth, which is the maximum data handling capacity per second for a memory storage device, has also gradually improved for Mobile DRAM memory, starting with LPDDR1 and increasing for later revisions.

Mobile DRAM Bandwidth Requirements

Within the next five years, applications such as tablet PCs are expected to require bandwidths in excess of 50GB/sec while smartphones are expected to require somewhere between 20 to 30GB/sec.

Four key factors determine the success or failure of any generation of Mobile DRAM. These factors, also known as enablers, are illustrated below :

The four key enablers are :

• Performance :
  Mobile DRAM needs to support applications that are ultimately deployed on mobile devices with large and high-resolution displays.
• Low power consumption :
  As application deployments are on battery-powered mobile devices, the longer the battery life, the better. Hence, Mobile DRAM should consume as little power as possible.
• Small/Thin form-factor :
  Mobile DRAM must be physically small so that it occupies very little board space on a mobile device.
• Higher Density :
  The newest generation of mobile devices have multi-tasking capabilities, such as letting the user listen to music while simultaneously using another app or feature of the device (such as browsing the device's phonebook). Advanced capabilities like these require higher density Mobile DRAM.

The next generation of Samsung's LPDDR memory promises to deliver up to four times the performance of conventional memory interfaces