• State TI Thinks Resolved
  • Locked Locked
  • Replies 4 replies
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 157 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

LMQ66430-Q1: Not to get 3.3V output

David (ASIC) Liu
Guru**** 176711 points
Part Number: LMQ66430-Q1

Tool/software:

Hi,

I am doing an automotive reference design with LMQ66420MC3RXBRQ1 but upgrade the 2A to the 3A(LMQ66430MC3RXBRQ1) version. But after putting the 3A version on it, I am not able to get the 3.3V output voltage. With the 5V input voltage, I am only seeing 0.2V output. Can you please take a look at the schematic and see why I am not getting the 3.3V output?

HSSC_Auto_Reference_Design_Schematic_Final.pdf

Thanks

David

  • 0
    TI__Mastermind 24115 points

    Hi David, 

    For the 3.3 V 3 A device, about 60 uF of effective output capacitance (after de-rating) is required for the device to be operational. For more information about this, please see section 8.2 of the associated datasheet.

    Additionally, please answer the following questions so we may better assist you:

    • What load are you attempting to run this device at when you are not getting 0.2 V output?
    • Does increasing the input voltage turn the device on?

    Thank you,

    Joshua Austria

  • 0 in reply to Joshua Austria
    TI__Guru**** 176711 points

    Joshua

    I am trying to output an 1A load with this device. 

    Below is a list of actions I did

    1. Remove C131, C133, and C134 10uF cap at the LMQ66430MC3RXBRQ1 input

    2. Remove U30 5V to 5V LDO

    3. Replace 5x10uF cap to 3x22uF cap at LMQ66430MC3RXBRQ1 output

    4. Supply 7V/3A at the LMQ66430MC3RXBRQ1 input and still not seeing the 3.3V output.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    TI__Mastermind 24115 points

    Hi David, 

    Our next recommendation for debugging is doing an ABA swap with the EVM. Please take the IC off of your system and place it on the EVM. Then please provide the input of the EVM with 7 Vin power supply with a 3 A current limit and see if an output can be observed at the EVM output terminals. This will help us determine if this issue is a device or system issue.

    Once this is done, please reply here with the results and I would be happy to assist you further.

    Thank you,

    Joshua Austria

  • 0 in reply to Joshua Austria
    TI__Mastermind 24115 points

    Hi David,

    As it has been sometime since I have heard from you, I will have to close this thread. Should you need further assistance, feel free to respond in this thread again.

    Thank you,

    Joshua Austria