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TPS62823: using ESR requirements for input capacitor

Eric Garner
Prodigy 180 points
Part Number: TPS62823

I'm using a TPS62823 in a 5V to 3.3 V step down application. In our application the power input input cable is very long and when plugged in we see an 8V transient as measured at the input capacitor:

Obviously this exceeds the recommended 6V max input for the TPS62823. I'd like to replace the input ceramic with something with a higher ESR like a tantalum or electrolytic to avoid this overshoot, but I do not see minimum ESR guidelines in the datasheet and webbench simulations with varied ESR on the input capacitor don't seem to effect stability which makes me think either something is wrong in the simulation or the datasheet guidance is incomplete. 

so I have two questions 1. is an input transient of that magnitude acceptable? and if it's not what's an acceptable value for input capacitor ESR 

  • 0
    TI__Mastermind 36981 points

    Hi Eric,

    The 8V on the VIN pin is not acceptable because it might damage the device. The required ESR is not defined for the input capacitor however, it is highly recommended to use a 4.7uF (min) to have an acceptable input current ripple.


    To suppress the voltage spike in the input supply during hot plugged, you want to consider adding a TVS diode on the front-end to clamp the voltage to 5.5V.

    Best regards,

    Excel