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AM3352 power domains

Nikhil Tiwari
Intellectual 575 points
Other Parts Discussed in Thread: TPS62142

Hi,

Is it neccassary to power up the devices as well as to provides the pull ups on signals with their respective power domain supplies (VDDSHV)? There might be some leakage if we use an external supplies as both 3.3V internal and external will have slightly different voltage levels other than this can there be any issues?

Thanks & Regards,

Nikhil 

  • 0
    TI__Guru 63155 points

    Please refer to to the "Steady State Max. Voltage at all IO pins" parameter in the Absolute Maximum Ratings table in the AM335x data sheet.

    Regards,
    Paul

  • 0 in reply to peaves
    Intellectual 575 points

    Hi Paul,

    Thanks for your reply. It is mentioned in datasheet that 'peripheral never sources a voltage outside the valid input voltage range,including power supply ramp-up and ramp-down sequences'.

    The PMIC outputs are not sufficient to power some devices like ethernet PHY and HDMI transmitter on our board. So we are using an external SMPS (TPS62142) for generating the 3.3V for these devices.

    The accuracy of SMPS is 1.8% and PMIC is 3% so in steady state the pin IO voltage will remain within the range required. But how can we make sure that during supply ramp-up and ramp-down same is followed? We can't make sure that PMIC 3.3V and SMPS outputs start ramping up and down at same time.

    In this case what is the suggestion for the IOs which are connected in between these devices? 

    Regards,

    Nikhil