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Power consumption issue on MSP430FR5739

SeaFesse
Expert 2690 points
Other Parts Discussed in Thread: MSP430F5438, MSP430FR5739

Hi  guys,

Any body can explain what cause the differences  consumption   between the two MCUs,MSP430F5438  and  MSP430FR5739 ?

According to the datasheet, MSP430FR5739 costs much more current than MSP430F5438 in the same LPMx.

They use the same core[MSP430Xv2] ,so it seems like a different  peripherals lead to this result.  Any clues will be appreciated.

 

  • 0
    Guru 58965 points

    Are you saying that the data sheet says FR5739 consumes more power than FR5738?  I did not see that.

  • 0 in reply to old_cow_yellow
    Expert 2690 points

    Hi , there！

    Thanks for your attention.   The chip I mean is MSP430F5438 .   I just want to know what  cause a  power consuptiom difference between the ordinary F5xx series and
    FRAM series.
  • 0 in reply to SeaFesse
    Mastermind 7395 points

    Hi,

    From the datasheet, FR573x power consumption is less than F543x power consumption for most operation modes.

  • 0 in reply to Avi Chami1
    Expert 2690 points

    MSP430F5xx

     

    MSP430FRxx

  • 0 in reply to SeaFesse
    Guru 227245 points

    One common mistake is to assume that there is such a thing like 'the low power mode x'.

    The so-called LPMs are just a combination of bit settings that do some specific work. Like disabling the DCO, disabling the SMCLK, the ACLK. Whether you will ever reach the valus in the datasheet, depends on your overall project parameters.

    One cannot compare LPM on one device with the 'same' LPM on another device. While this is somewhat reasonable on devices of the same family, it completely fails when comparing devices with different clock modules.

    The FR, for example, does not have a DCO. It rather has calibrated discrete oscillators which are enabled or disabled. There are also other structural differences which make a direct comparise pretty useless.

    In a real project you'll likely see that the resulting power consumption of the FR5 is much less than that of the F5 because of all the things that are required in addition to the plain 'LPM current' of the F5 which aren't added on the FR5. (or already counted in).

    And finally, you can simply switch off teh FR5 and revive it when needed, without losign th eprevious state information. Giving you an LPM6 with 0 current :)

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