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PCM1753-Q1: power consumption I2C

domenyko
Genius 9655 points
Part Number: PCM1753-Q1

Dear all,

one of my customer is trying to estimate the power consumption associated to the I2C portion of the PCM1753-Q1.

I know that it depends on the pull-up resitances, but is there any formula to estimate the Irms which take in account the data rate of the I2C and a typical SDA transaction ?

regards,

Domenico

  • 0
    TI__Guru 53283 points
    Hi Domenico,

    That is a bit hard to say for sure, but I think from a power supply design standpoint you should assume the worst case current. That would be when both SDA and SCL is low. For example, if the pull-ups are 2kOhm and the bus is at 3.3V, then you could expect Imax to be 2*(3.3V / 2kOhm) = 3.3mA.

    During an I2C transaction, you can estimate that the SCL has approx. a 50/50 duty cycle. It is also somewhat reasonable to estimate the SDA will have about a 50/50 duty cycle. The RMS value of a square wave with a 50/50 duty cycle is Ihigh/sqrt(2). So the Irms value can be estimated as 2*(1.65mA/1.414) ~= 2.333mArms.

    Thanks!
    Paul
  • 0 in reply to Paul_Frost
    TI__Genius 9655 points

    Hi Paul,

    thnaks for answer.

    I'll proceede according to your suggestions.

    regards,

    Domenico