• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Subscribers 65 subscribers
  • Views 940 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.

TPS2491: About out put cap

Tsukui Yusuke
Guru 21930 points
Part Number: TPS2491

Hi,

Could you tell me about TPS2491 out put cap?
My customer do not plan to install output cap.
Can this device be used with no output cap?
Please tell me if you have any concerns and advice.

Best Regards,
Yusuke/Japan Disty

  • 0
    TI__Genius 10370 points

    Hi Yusuke-san,

    This device does need an output capacitor with a minimum value of 10uF. The bigger the output cap, the more stable the output voltage is when transients occur. Our team has created specific calculator tools to help with the design of our hot-swap controllers. 

    You can find it by going to www.ti.com/hotswap ==> click on “Tools & software” ==> then click on “Hot Swap design calculator tools”

    For help on filling out the cells on the excel spreadsheet, our team created video tutorials on how to fill out the hot-swap design calculator spreadsheet. They explain cell by cell what each one means and how to enter the correct value. The videos are at www.ti.com/hotswap ==> Click on “Support & Training” tab.

    Thank you for using TI parts for your project :-)

    Best Regards,

    Aramis P. Alvarez

  • 0 in reply to Aramis P. Alvarez
    Guru 21685 points
    Hi Aramis,

    Thank you for your kind response. I'm working with Yusuke in Japan Disty. Let me ask more about requirement of minimum output capacitance. I understand that you recommend to place more than 10uF as output capacitor, then what do you have concern if they use lower capacitor or no capacitor? Is there the possible of unstable operation or just see larger transient?

    Best Regards,
    Satoshi
  • 0 in reply to S.Satoshi
    TI__Genius 12621 points
    Hi Satoshi-san,

    Aramis is out of the office and will return next week. In the meantime, I can assist.

    Without output capacitance, the TPS2491 can have trouble regulating. Especially when hot plugging any load into this, this will seem like a short circuit from the IC’s point of view and can cause the IC to reset.

    A 10uF output cap is not needed directly at the output of the TPS2491. It is ok if there is other bulk capacitors downstream or placed further away, but still connected to the TPS2491 output node. The goal is just to ensure that the TOTAL output capacitance connected to the TPS2491's output pin is >10uF.

    Usually whatever load is connected to the TPS2491 will have some input capacitors greater than 10uF total.

    Thanks,
    Alex