It’s Time To Fix The NVM Shortfalls In Mobile Devices
April 30, 2010
By Charlie Cheng, Kilopass Technology Inc.
The world of mobile devices owes much of its phenomenal progress to semiconductor advances. From the bulky Motorola “brick” in 1980 to today’s palm-size handset, integration, power, and cost have seen similar advances to those of computers. Today’s smart phones will continue to pack more functionality at the same sales price, while feature phones will continue to break low-water marks on bill-of-materials (BOM) cost.
In a teardown of a typical smart phone, we can see that it is already a very integrated system. There are very few DRAM and NAND flash components and fewer digital logic chips, which are easiest to integrate because of available EDA tools and methodologies. Also, the analog/mixed-signal chips are becoming multi-functional. But there are 10 to 20 nonvolatile memory (NVM) chips, such as EEPROMs and serial flash chips, spread around the printed-circuit board, each next to a digital or mixed-signal chip.
After each power reset, the EEPROMs provide software programs, user IDs, configuration settings, and so on—a small amount of code, but critical to phone initialization. At approximately $0.20 per chip, total EEPROM cost adds up to a non-trivial $2 to $4 per system. What’s more, these NVMs take up space, draw power, and likely contribute to the industry’s field returns of greater than 1%.