Transition from NOR to NAND flash memory a key
A OneNAND flash memory chip perched on a cell phone.
[This article discusses memory products including those from Samsung. The author works for Samsung Semiconductor.]
At the heart of the digital devices in our pockets is a critical but much-misunderstood element—memory. Each generation of digital devices needs more of it, yet all memory is not created equal. In fact, advances in flash memory have laid the technical foundations for a slew of new portable digital offerings that will allow even more electronic wizardry on Smartphones, PDAs and portable media players.
The key is the development of better NAND-based flash memory, which is superior to the NOR memory commonly found in today's Smartphones and Windows Mobile devices (see the sidebar for descriptions of these different types of memory). But as we stretch the boundaries of what these devices do, turning them into cameras, video and audio players, and portable media centers, the demands on the memory in these devices goes up and up, making the use of NAND memory not simply of interest, but a necessity.
Smartphones are making significant inroads into consumer and corporate markets, and PDAs are increasing in sophistication. Application processor clock rates for Smartphones will reach or exceed the roadrunner-like speed of 750 MHz by early 2006, and 3G processors will enable wireless Wide Area Networks to accommodate data transfer rates of up to 3 Mbps—60 times faster than current 2.5 G networks. Within the next year or two, low power Wi-Fi modems will enable thousands of ad hoc networks for multimedia file sharing at speeds exceeding 50 Mbps. The picture will get even better: devices will have three-inch LCD screens with VGA resolution, supporting richer user interfaces, watch-as-you-go video, and "personal library" imaging.
Smartphone operating systems such as Windows Mobile, Symbian, PalmOS, and even Linux, will sport a bevy of advanced applications including Microsoft Office or Office-like productivity suites, video camera applications, video phone apps, time-shifted mobile video, still camera, image editing apps, 3D gaming, and e-mail.
A multitude of capabilities are getting built into the Smartphone.
The rise of flash memory
The key to the seemingly endless number of new applications popping up everywhere in portable technology is the most revolutionary means of data storage introduced over the past 50 years: flash memory. Flash memory is to mobile devices what cubicles, near instant-on office lighting and high speed elevators are to skyscrapers—the wellsprings of true workspace efficiency.
Over the past couple of years, the complexity of system performance requirements for Smartphones, advanced PDAs and Portable Media Centers has been taxing traditional memory solutions in much the same way as the Holland Tunnel is filled to capacity during the Manhattan rush hour. There just aren't enough lanes for all the vehicles, and so traffic slows to a snail's pace.
The complexity of the Smartphone's memory subsystem, in effect, is beginning to mandate an upgrade from what have been the most popular mobile memory alternatives until now: SDRAM and NOR-based flash memory. The solution appears to be a transition to NAND, a versatile memory that's 60 times faster and 80 times less energy-hungry than the flash memory of yesteryear, NOR.
NAND or NOR?
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