Traversing the show floor at the DESIGN West exhibition in San Jose, California, last month there seemed to be plenty of discussion about low power microcontrollers for applications such as battery-backed wireless sensor networks and for autonomous systems based on energy harvesting.
And there was also promotion and claims for "Wolverine" from Texas Instruments, a version of the MSP430 16-bit microcontroller built on a low-leakage current 130-nm manufacturing process and with ferroelectric RAM non-volatile memory on chip. One of those claims was "World's lowest power MCU platform."
But according to Microchip executives a lot of the low power kudos should be coming the way of Microchip's established PIC range of microcontrollers with XLP technology.
Eric Lawson, public relations manager for Microchip Technology Inc., has written an email to EE Times
with a comparison of current consumption figures drawn from PIC and Wolverine datasheets (see table below).
Click on image to enlarge.
Table and references taken from email to EE Times
Of course the devil is in the detail. Current drawn is not the same as power consumption.
And it may be that TI's claims are based on the fact that it has FRAM non-volatile memory on chip. Perhaps in a real-world application where a device is switched off and powered up repeatedly the energy cost in terms of writing data to, and reading data from, non-volatile memory is lower with FRAM than with flash memory. But the final result and true comparison would depend on the detail of the amount of data stored, and the off/sleep/standby/active duty cycles and application and processing demand.
This all makes a good argument for a benchmarking exercise where competing microcontrollers can go head-to-head.
It is wise to ask not only who has the lowest power microcontroller but also under what circumstances? Is it Microchip, Texas Instruments or perhaps another company?
Related links and articles:
TI Wolverine Press Release: http://newscenter.ti.com/index.php?s=32851&item=123083
TI Wolverine White Paper: http://www.ti.com/lit/wp/slay019a/slay019a.pdf
Microchip PIC16LF1509 Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/41609A.pdf
Microchip PIC24FJ64GB004 Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/39940d.pdf
Microchip PIC24FJ128GA310 Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/39996f.pdf
News articles: FRAM helps TI cut power for Wolverine MSP430 platform
PIC MCUs hit a low point (in terms of power)