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TPS65381A-Q1: VDD5 Output Current and Vtrack

Wayne Liu
Expert 8705 points
Part Number: TPS65381A-Q1

Hi,

I have two questions:

1. If I need a high accuracy VSOUT1, can I connect Vtrack1 with external voltage reference to get higher accuracy?

2. My customer reported when they use an electrical load to test the output current of VDD5,  no load on other output, when the output current is 147mA, the output will be off soon, the 147mA is much less than 300mA maximum in datasheet. Same situation on VDD6. Since this is in debug stage, we cannot read the fault status, how should I debug this issue? Thanks.

  • 0
    TI__Genius 17380 points
    Hi Wayne,

    The TPS65381A-Q1 technical owner is on business travel until the 28th. I will try to provide some assistance / gather preliminary information until he returns.

    To help expedite his help, can you provide scope shots of the VDD5 output and VDD6 input? Alternatively, to talk with the PMIC to read the fault status, can you connect the device to an EVM MCU?
  • 0
    TI__Genius 9380 points
    Wayne,
    The tracking offset between the VTRACK1 and VSFB1 pins is ±35 mV. That's about ±1% if VSOUT1 was 3.3V. With an external reference of 1% you will be at about the same accuracy as the internal reference of ±2%. If you were targeting 5V or higher on VSOUT1, and you used an external regulator better than 1%, then yes you can get a higher accuracy.

    Question 2 leaves many questions for me. If VDD5 works for a little while then stops, and you say that this is similar situation as VDD6, my first thought is to make sure the power pad on the bottom of the IC is soldered to a pad on the PCB and the pad is connected to the ground plane. From your first description it sounds like it's getting hot and the thermal protection is turning the part off.

    If my understanding of your problem is not correct, please explain the problem in more detail and provide setup and other test information.
  • 0 in reply to Gordon Varney
    TI__Expert 8705 points
    Kevin, Gordon,
    Thanks for your support. We have found the cause, it is the problem of load, 65381 can output 300mA. Let's close this question.