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DS3231M What is the definition of a I2C Inactive for battery mode.

Category: Datasheet/Specs
Product Number: DS3231M
Software Version: Not Applicable

Hi,

I have a question about specifications. To have the DS3231 RTC in the lowest current consumption mode it must run on battery with its I2c inactive, see  Maxim Integrated page 3 section VBAT Current Consumption. The definition of what an inactive I2C interface is is not clear specified in the specifications.

I use the chip as a watch dog to periodic power up a system using its Int/SQW open collector output activating a Pmosfet which acts as a switch to the system to be power up. In a power off mode the  DS3231 I2C interfaces is unpowered and down/low including, the RTC chip receives only power using a battery. Is in this state, the I2C considered inactive and so the current consumption 2uA.?

Is the definition of an inactive I2c interface in this specification one with inactive not changing SCL and SDA pins independent of the voltage levels high or low at these pins, in my case active low because of the lac of VCC at the microcontroller.

Hope someone can clear this up.

Thanks

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  • FormerMember
    FormerMember
Jul 28, 2023 +1 verified
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  • FormerMember
    +1 FormerMember
on Jul 28, 2023 7:40 PM

I2c active means i2c sending or receiving data, I2c inactive means i2c NOT sending or receiving data, so, for your case, it is in I2c inactive mode. But looking the data sheet of DS3231 https://www.analog.com/media/en/technical-documentation/data-sheets/DS3231.pdf I do Not see 2uA at page 3,  there is a "Timekeeping Battery Current" typ -0.8uA  max=3uA , I assume you were referring those number 

  • Hi,

    The DS3231 is a different chip compared with the DS3231M, the DS3231M has a current  of 2uA the DS3231 has a current of 0,8uA. Thanks for your response

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