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Original question:

TPS22916: specifications.

TPS22916: Input vs output capacitor

Chris Schramm
Intellectual 590 points
Part Number: TPS22916

Dear TI-Team,

We want to use TPS22916 to control a MCU's VUSB input which will only be connect if the board's VIN > 4.5V (VIN could be a USB charger or a solar cell)

in this post
https://e2e.ti.com/support/power-management/f/196/t/740376

 recommends to use an input capacitor with x10 capacitance of the output. Well, the VUSB of the MCU recommends a 10uF cap, but I can't imagine we  had to use a 100uF cap for TPS22916's VIN :)

Please advise

Thanks!

Chris

  • 0
    TI__Mastermind 34905 points

    Chris,

    While we recommend a 10:1 input to output capacitor ratio on the device, the reality is that this is based on the power supply’s ability to handle the turn on transients of the device. The TPS22916 has a pretty controlled slew rate. As long as the power supply can handle the turn on of the device, then the 10:1 ratio is not needed (even 1:1 is okay). If the output capacitance is larger than the input capacitance, then if the input drops very suddenly, the output voltage will drop slower than the input and reverse current may flow through the device.

  • 0 in reply to Timothy Logan
    Intellectual 590 points

    Thanks Timothy. I‘ll use 4.7uF out and 10uF in