By Larry Morrell, John Schroeter, Impinj; and Deepak Savadatti, Primarion
If there is anything hot that electronics markets (for example, RF, display driver, secure media, and power management) have in common, it's that they operate in extremely tight market windows, and race to deliver of the kinds of value-added differentiation that fuels real growth. But they share other important attributes, as well: many applications are enabled, made more cost-effective, or are performance-enhanced by the integration of small bit-count multiple times programmable nonvolatile memory (NVM). And when you add to the mix the fact that embedded NVM also contributes to improved manufacturability, faster time to market, and higher product quality, it becomes all the more clear why embedded NVM is one of the key game-winners for these extremely competitive markets—and the power management segment is no exception. But as we'll also see, no ordinary NVM will do.
Toward a more logical NVM
While today's designers have numerous NVM options, the field narrows to those that can be embedded at low cost, and yet also exhibit high performance and application flexibility. For certain applications, those objectives rule out a number of possibilities. For example, while traditional laser fuses may be appropriate for bits in the single digits, they are one-time factory programmable. Forget about iterative precision analog trim, forget about field upgrades, and forget about reliability—the many shortcomings of poly fuses are well documented and well known. A better option is Flash, but then you can forget about low cost; the process adders required to fabricate this NVM architecture run into the hundreds of dollars per wafer. EEPROM, on the other hand, has been around for quite some time. As such, it is relatively inexpensive… but not when you consider that it is limited to older process technologies, which also limit performance to unacceptably low levels. As for the newer breeds of embedded EEPROM, which, like Flash, require additional mask layers and process steps, you can erase the cost advantages of the previous generation technology.
The solution that many players in critical hot markets have turned to is NVM designed in Logic CMOS. Not only is it compatible with the straight CMOS process objectives of hot market applications like power management, Logic CMOS's powerful combination of high-performance and low cost make it ideally suited to embedded NVM.
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