Sunday, June 29, 2014

Power-Sipping Microcontrollers Use FRAM

Emerging technologies and new tech terms are something of high interest to me, so when I saw a couple recent articles about microcontrollers with FRAM, I needed to know more.

FRAM (also written as FeRAM), or ferroelectric random-access memory, is defined by Wikipedia as,
"...similar in construction to DRAM but uses a ferroelectric layer instead of a dielectric layer to achieve non-volatility. FeRAM is one of a growing number of alternative non-volatile random-access memory technologies that offer the same functionality as flash memory. FeRAM advantages over flash include: lower power usage, faster write performance and a much greater maximum number of write-erase cycles (exceeding 1016 for 3.3 V devices). Disadvantages of FeRAM are much lower storage densities than flash devices, storage capacity limitations, and higher cost."
The article titled "Comprehensive Ultra-Low Power FRAM Microcontroller Platform from Texas Instruments" looks a bit like it came directly out of the marketing department rather than the engineering department. Although I guess most, if not all, press releases are generated by marketing departments, so the wording shouldn't really surprise me. The numbers in the article may not be incorrect, but they sure are presented in a hard-to-believe so-much-better-than-the-previous-model way. The article says,
"Texas Instruments (TI) today announced its comprehensive ultra-low power FRAM microcontroller (MCU) platform with all the necessary hardware and software reduce energy budgets, minimize product size and enable a battery-free world. TI's new MSP430FR59x/69x FRAM MCU families...range from 32 to 128 KB embedded FRAM. These MSP430™ MCUs are ideal for smart utility metering, wearable electronics, industrial and remote sensors, energy harvesting, home automation, data acquisition systems, the Internet of Things (IoT)...ultra-low-leakage (ULL) proprietary technology with embedded FRAM delivers the world's lowest system power with active power of 100 uA/MHz, accurate-RTC standby power of 450 nA...and an enhanced scan interface for flow metering that can operate while the system is in standby, resulting in 10 times lower power...FRAM is the only non-volatile embedded memory that can be written at 8MBps in under 800uA – more than 100 times faster than flash
The new MCUs sound like the definition of innovation -- "a battery-free world," "world's lowest system power," "10 times lower power" and "more than 100 times faster." If those terms are relevant and delivered on a cost-competitive basis relative to alternative components, there are definitely applications where it would be worthwhile to evaluate the IT FRAM microcontrollers. The Wikipedia article explains some aspects of the FRAM advantages,
"Flash works by pushing electrons across a high-quality insulating barrier where they get "stuck" on one terminal of a transistor. This process requires high voltages, which are built up in a charge pump over time. This means that FeRAM could be expected to be lower power than flash, at least for writing, as the write power in FeRAM is only marginally higher than reading...Flash memories commonly need a millisecond or more to complete a write, whereas current FeRAMs may complete a write in less than 150 ns."
 To benefit from the FRAM, MCU-system designers will have to focus on where the FRAM advantages over competing memory forms will pay big benefits. Two use cases that seem like the best candidates are energy-harvesting and remote sensors.

If you had some sample Texas Instruments FRAM MCUs, what would you use them for?


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