TMS320F28377D-EP: Question: Power supply sequence

miyagawa shinichi said:

1. Supply ramp rate

    About: supply ramp rate requirement in Datasheet 4.7.1 table 4-3

   Question: Is the requirement applied to only power-on state or power-on and power-off state? 

This is only for the power up state.  The only thing to avoid with power down, is:

-VDD should not exceed VDDIO

-Making sure there isn't an input to the device that will be >VDDIO as it ramps down.

miyagawa shinichi said:

2.VDDIO and VDD

   About: Datasheet 4.7.1 discription: The voltage on VDDIO shold be greater than VDD or no less than 0.3V bellow VDD at all times.

   Question1: Is the requirement applied to power-off state?  ( in power-off state : /XRS is drived to low by external circuit. )

   Question2: If VDDIO is less than 0.3V bellow VDD, TMS320F28377D-EP's internal circuit iwill be dameged? 

   Background: Shottkey diode can`t use for high temeprature application, because of the diode's leakage current is too much at .high tempeature.

Yes, I would want to ensure this compliance is met, even on power down.  The risk if VDD>VDDIO+0.3V is that we reverse bias some of the internal transistors and we get current sourced from VDD into VDDIO.

Best,

Matthew