• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 188 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.

TPS62821: Absolute max rating about SW

Shumpei Miyano
Prodigy 100 points
Part Number: TPS62821

Tool/software:

Hi,

We have two questions about TPS62821.

1. When the power supply of the product using TPS62821 is turned off , as shown in the attached waveform, for a short period of time the voltage of Vsw is higher than the voltage of Vin.

The datasheet states that Vsw is Vin+0.3V for Absolute Maximum Ratings , but up to what voltage is actually permissible ?

2. Are there any relaxation conditions, such as a period for which Vsw can exceed Vin+0.3V without any problems?

Thank you.

inquiry.pdf

  • 0
    TI__Mastermind 22080 points

    Hello Shumpei,

    thanks for reaching out in E2E.

    Here are my comments to your questions:

    1. Vin + 0.3V is the actual absolute maximum rating for Vsw as stated in the datasheet. The only exception is the typical overshoot at the rising edge when the SW node is switching. Here 10V is the absolute maximum rating, as long as the duration is less than 10ns.

    2. Vsw can not exceed Vin+0.3V without any problems. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device.

    If it is possible to control EN separately then you could disable the TPS62821 before turning off Vin.

    I assume EN is connected to Vin in your case. I think the active discharge feature would ramp down Vsw quite fast if the EN signal would drop below 0.4V in the same moment when Vin turns off. From your scope picture it looks like Vin is dropping down to 2V in the first moment. If possible you could try to use a voltage divider or a FET to generate a smaller EN signal from Vin (EN voltage ≥1V for high and ≤0.4V for low), which disables the TPS62821 in the moment of the first Vin drop.

    Best regards,

    Andreas.