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DM365 RTC power consumption

Shahrad
Prodigy 180 points
Other Parts Discussed in Thread: OMAP3530

Hi,

We want to use the RTC embedded in PRTCSS module of DM365, but apparently from lab tests, the power consumption of RTC is very high (compare to RTC chips). So wonder that if there is any specific settings and/or silicon revision of DM365 (like OMAP3530, mentioned in one white paper) that could reduce the power consumption of RTC.

 

Thanks,

Shahrad

  • 0
    TI__Mastermind 41665 points

    Shahrad said:
    So wonder that if there is any specific settings and/or silicon revision of DM365 (like OMAP3530, mentioned in one white paper) that could reduce the power consumption of RTC.

    What kind of power consumption are you seeing? In general I do not believe there are any special settings, or any changes in silicon revision, that would take the PRTCSS very low, I believe it is typically ~100-200uW.

  • 0 in reply to Bernie Thompson TI
    Prodigy 180 points

    Hi

    Thanks for reply.

    We also kind of get the same value, around 160uW. But this is too much compare to RTC chips with 0.25 uW.

    Thanks,

    Shahrad

  • 0 in reply to Shahrad
    Prodigy 180 points

    We want to have small coin cell battery with long time life for our device, and seems that DM365 RTC is not good choice and we need to use external I2C. Am I right? Do you have any suggestions?

    Seems in the OMAP, the power of RTC could be seperated from the rest, by setting a bit? Is this valid?

  • 0 in reply to Shahrad
    TI__Mastermind 41665 points

    Shahrad said:
    We want to have small coin cell battery with long time life for our device, and seems that DM365 RTC is not good choice and we need to use external I2C. Am I right? Do you have any suggestions?

    That is my impression, at ~160uW it would only be effective feeding off a much larger battery unless the coin cell was only expected to be used for short periods, I am not very familiar with external RTCs so I cannot really offer much suggestion there.

    Shahrad said:
    Seems in the OMAP, the power of RTC could be seperated from the rest, by setting a bit? Is this valid?

    I am not sure which specific bit you mean? The PRTCSS is already powered separately from the rest of the chip, so the ~160uW you are measuring would be only on its two rails, not to the rest of the DM365 supply pins.

  • 0 in reply to Bernie Thompson TI
    Expert 1840 points

    Hi,

    To step over the obstacle which relate to dm368 RTC we desire to use DS 1337 external RTC. We saw that inside of kernel of Appro IPNC package has already had the driver for that. My question is can you give some helps for replace the internal RTC by external RTC? Thanks.