• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Answers 2 answers
  • Subscribers 46 subscribers
  • Views 243 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.

DAC8760: Power sequence of DAC8760

MESH
Intellectual 830 points
Part Number: DAC8760

Hello,

I considering analog output circuit board that uses DAC8760.
DAC8760 has three power input of DVDD, AVDD and AVSS.

I would like to confirm power sequence for power up and power down of DVDD, AVDD and AVSS power supply.
In the description of the DAC8760 data sheet, I could not find the description about the power sequence.

Please tell me about the power sequence for DAC8760.

Regards,

MESH

  • 0
    TI__Guru* 92655 points

    MESH,

    The datasheet does have a power supply sequence shown in section 8.3.7 on page 30 of the datasheet. Admittedly, I usually see this in the Power Supply Recommendations in section 10. You can look it up in the datasheet, but I've clipped it out here:

    Joseph Wu

  • 0 in reply to Joseph Wu
    Intellectual 830 points

    Hi Joseph,

    Thank you for your reply.

    I will check detail of section 8.3.7 on the data sheet.

    If I have any additional questions, I'll add them here.

    Regards,
    MESH
  • 0 in reply to MESH
    Intellectual 830 points

    Hi Joseph,

    I checked section 8.3.7 on the data sheet.

    Just in case, let me confirm that the following understanding is correct.

     

    1. The DAC8760 is not damaged by the order in which the AVDD power supply and the DVDD power supply are turned on. (I am concerned about the occurrence of latch-up etc.)

    2. A software reset occurs when the DAC8760 starts operating, regardless of the order in which the AVDD power supply and the DVDD power supply are turned on. (including cases where it takes 50 μsec or more from the DVDD power supply rise to the AVDD power supply rise).
    The software reset allows the DAC8760 to operate normally in any power-up case.

    Regards,

    MESH

  • 0 in reply to MESH
    TI__Guru* 92655 points

    MESH,


    1. I'm not familiar with any latchup issues with the power supply sequencing of the device. They should be independent of each other, and not influence any cross-current draw.

    2. The power-on reset is a circuit reset and not a software reset. There is a circuit that outputs a /RESET signal that starts out low at the power up. Once some voltage threshold is reached, the output of that /RESET signal goes high. This /RESET is connected to the digital section of the device.


    Joseph Wu

  • 0 in reply to Joseph Wu
    Intellectual 830 points

    Hi Joseph,

    Thank you for your reply.

    I'm sorry, but let me check the following again.

    1. I want to make sure the DAC8760 doesn't break when AVDD is turned on after DVDD is turned on.

    2. I want to confirm that the DAC8760 operates normally by power-on reset or software reset regardless of the order of turning on the AVDD power supply and the DVDD power supply.

     

    Regards,

    MESH

  • +1 in reply to MESH
    TI__Guru* 92655 points

    MESH,


    As the datasheet states, the preferred order is that the analog supply comes up first, and then the digital supply comes up. When this is not the case, the digital supply can come up first as long as the analog supply reaches 5V within 50us.

    However, if neither of these can be done (which means that the digital supply comes up first, and the analog supply comes up after longer than 50us), TI recommends that a software reset command is sent after both supplies settles. I'm not aware of any damage to the device that could happen, but the reset is to ensure that the device does see a reset at the start, if the power-on reset to the device is not effective from the supply order.


    Joseph Wu

  • 0 in reply to Joseph Wu
    Intellectual 830 points

    Hi Joseph,

    Thank you for your reply.

    I will  do my best to design the circuit to meet recommended AVDD and DVDD turn on conditions.

    Regards,

    MESH