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TPS54302: Overshoot and undershoot

Danilo A.
Mastermind 26960 points
Part Number: TPS54302

Hi Team,

Our customer is using TPS54302 on their application with input voltage of 12V to 24V, output voltage of 3.8V and max output current of 2.5A. He noticed that there are high overshoot and undershoot voltage during dynamic load steps of 100mA to 2A. The overshoot/undershoot voltages are about 600mV. Please refer to the schematic diagram and waveform below. What could be the cause of the overshoot/undershoot?

Regards,

Danilo

  • 0
    TI__Expert 4795 points

    Hi Danilo,

    What's the output capacitor effective capacitance? What's the slew rate of load step? Thanks.

  • 0
    TI__Genius 9400 points

    Hi Danilo,

    Is this configuration working stability in both light load and full load ? and may I check with you again about Vincent's question ?

    BRs,

    Young

  • 0 in reply to Young Zhao
    TI__Mastermind 26960 points

    Hi Team,

    Thank you for your response.

    According to the customer, on the 3.8V output he had connected additional 2x10uF + 2x100nF + 2x33pF + 2x12pF near the modem power supply, and 1x100nF as input capacitor for LDO. In their test they didn't power on the modem and the LDO is only for powering MCU and memory. The power consumption on 3.8V is no more than 50mA. He also added that they use Maynuo electronic load. I'm still waiting for the slew rate. 

    I will also check if the overshoot and undershoot are present in both light load and full load.

    Regards,

    Danilo

  • 0 in reply to Danilo A.
    TI__Genius 9400 points

    Hi Danilo,

    thanks for checking this .

    Please let me list the items need your help .

    1, Effective Cout, the derated value at 3.5V or share us the D/S and part number to check it.

    2. slew rate of load step

    3. Is this configuration working stability in both light load and full load ?

    BRs,

    Young