• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 47 subscribers
  • Views 112 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

AMC7836: Power Sequence order.

Dinesh S
Prodigy 10 points
Part Number: AMC7836

we are using AMC7836 in our Design, Where we have connected power rails in the below fashion,
AVCC_AB(Pin Number:20) and AVCC_CD(Pin Number:57) --> 12V
AVDD(Pin Number:50) and DVDD(Pin Number:63) --> 5V
IOVDD (Pin Number:01) --> 3V3

From Datasheet We understand its not required to follow the above sequence,

Above snip is from data sheet page number 78.

We understand that, its not required to follow the above sequence,

Our Board power sequence will be in the below order of
12V-->3V3-->5V

Can we follow the above order ?

Also can we know, is there any maximum time of deviation for Power Sequence.

Whether can we give
Case1: 12V @0s-->3V3@10Seconds-->5V @120 Seconds
Case2: I shall be giving 12V and 3v3 but not 5V for few minutes, such as 10Minutes

  • 0
    TI__Mastermind 18546 points

    Hi,

    There is no power sequencing required for this device. 

    The preferred (not required) pin order for applying power is IOVDD, DVDD and AVDD, AVCC and lastly AVEE, AVSSB, AVSSC, and AVSSD. When power sequencing, ensure that all digital pins are not powered or in an active state while the IOVDD pin ramps. Proper sequencing of the digital pins can be accomplished by attaching 10-kΩ pullup resistors to the IOVDD pin, or pulldown resistors to the DGND pin. See the supply voltage ranges in the Recommended Operating Conditions table.

    Since there is no preferred power sequence scheme, Case 1 and Case 2 are valid. Having said that, I wouldn't recommend this.

    Regards,

    AK

  • 0 in reply to Akhilesh K
    Prodigy 10 points

    Hi Akhilesh,

    Thanks for the response !!

    Now, can we know is there any maximum time constrain for enabling the Power rail i.e 5V ?

  • 0 in reply to Dinesh S
    TI__Mastermind 18546 points

    Hi,

    I will check this with my design team and revert back.

    Regards,

    AK

  • 0 in reply to Akhilesh K
    Prodigy 10 points

    Hi Akhilesh,

    Any update from your side.

  • 0 in reply to Dinesh S
    TI__Guru 52683 points

    Hi Dinesh,

    Do you mean that your system's 5V supply is slowly ramping for 120 seconds, or that it stays low and then quickly rises to the final value in a relatively short period?  If the rate is slow, then I recommend connecting the RESET pin to GND until the supplies are established.

    A long delay is not an issue, the only potential risk is a very slow slew rate in the supply, as the value could float around the POR threshold for an unreasonable time.

    Thanks,

    Paul