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Embedded memory for sensor data acquired by CC2650

PATRICK OHARA
Genius 3205 points
Other Parts Discussed in Thread: TPS62740, CC2650, CC2650STK

Hello,

We have a sensor that we'd like to acquire data from and store it near the CC2650 (as part of a module we're making). We find the internal memory integrated on the CC2650 to be inadequate for our purpose. We'd like to add ~2Mb of external memory. We can use either I2C or SPI to communicate to the memory. Can anyone suggest a suitable ultra low power memory chip. A related question, would we benefit from a buck regulator (like a TPS62740) to power the memory?

Thanks,

Patrick

  • 0
    TI__Guru** 105180 points
    Hello Patrick,

    Hopefully someone who has used these parts in actual designs can chime in. TI uses the Winbond SPI flash on the SensorTag (CC2650STK).

    Best wishes
  • 0 in reply to JXS
    Genius 3205 points
    Thanks JXS, that seems about as good as any. No doubt a lot of thought was put into the initial selection for the SensorTag.
  • 0 in reply to PATRICK OHARA
    TI__Mastermind 29650 points
    What is your system supply voltage? Depending on how many external circuits you hae ve, overall current might be reduced if you are able to run all circuits on 1.8V (incl CC26XX in external regulator mode) using a separate buck converter to power all the ICs.

    Regards,
    Svend
  • 0 in reply to svendbt
    Genius 3205 points
    Hey Svend,
    Just wondering, I thought that one of the big advances of the 26XX is the inclusion of an internal Buck Regulator. If so, is there really a benefit to an external Buck? Our basic idea is a 2650 with a power amplifier and 16Mb (2MB) of Flash for sensor data storage (data logging). I'd appreciate your comments on the value of a Buck in this application.

    Thanks,
    Patrick
  • 0 in reply to PATRICK OHARA
    TI__Mastermind 29650 points
    Hi Patrick,

    The on-chip buck converter on the CC26XX (outputting 1.68V) is not able to power external circuitry while in standby as it is duty cycled in this mode. The available current from it in standby is therefore extremely limited.

    If all your external circuitry also can run on e.g. 1.8V you can reduce the overall current by having them all powered by an external buck converter though it really depends on your use case. A solution that will for example very seldom use the radio but has a PA with high leakage current can for example benefit from the TI TPS62740 where you can switch off a separate supply rail powering the PA.

    Regards,
    Svend