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Power sequence of ADV7619

Question asked by ggottawa on Dec 19, 2013
Latest reply on Dec 19, 2013 by ggottawa

Hi,

 

I have several questions on power sequence of ADV7619 as shown below.

 

  • For the power-up sequence of ADV7619, Datasheet of ADV7619 shows two suggestions:

     a) 3.3V needs to be turned on before 1.8V

     b) assert all supplies simultaneously, but ensure that a lower rated supply does not go above a higher rated supply level

    

     For option a), what is the minimum wait-time between 3.3V & 1.8V?

     Also, is this wait-time controllable by software during the initialization of ADV7619?

 

     For option b), is there any guideline/suggestion on implementing “ensure that a lower rated supply does not go above a higher rated supply level”? 

  • In the reference design (schematics of the evaluation board, EVAL_ADV7619_7511_rev1p1.pdf), 3.3V & 1.8V are produced from 5.0V input: 3.3V is through U14 while 1.8V is through U16. By the way, enable signals are a bit different. Enabled signal of U14 is tied to 5V while the enable signal of U16 is tied to 3.3V. Is it how the correct power sequence (3.3V first & 1.8V later) is ensured?

 

Thank you.

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