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TPS65381A-Q1: How to control POWER SEQUENC of TPS65381A-Q1

Lin_Charles
Expert 4260 points
Part Number: TPS65381A-Q1

Hi team,

   I want to use 65381 to power 28379, VIN=12V, V1=1.2V/0.5A, Vo2=3.3V/0.3A.

  1. I am curious about if we can control the power sequence of these two supply? When it powers up, 3.3V enable first then 1.2V. When it powers off, 1.2V disable first then 3.3V.
  2. How about the power dissipation of this application?

  • 0
    TI__Mastermind 49171 points
    Hello Charles,
    Your questions have been assigned to the applications specialist for this device who is on business travel. He will respond as soon as he has some availability.
    Thank you for your patience.
  • 0
    TI__Mastermind 20590 points

    Hello Lin Charles,

    There isn't a configurable option for the sequencing on the TPS65381A-Q1 device.  The device will ramp the VDD1 (core rail LDO controller) which can be used for the 1.2V and VDD3/5 (configurable 3.3/5V regulator) starting at the same time with the VDD1 ramp being "inside" the VDD3/5 ramp as shown in Figure 5-1. Power-Up and Power-Down Behavior of the datasheet.  NRES pin (reset output) will be held low until the voltage monitoring for the rails has crossed their respective undervoltage (UV) thresholds plus the configurable reset extension time.  On power down the ramp down and discharge of the rails will depend on the integrated discharge resistance plus the external load on the rail, and NRES will also be pulled low during power down. 

    There is a power estimator for the device found on this FAQ: