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REF3025: REF3025 Step Response

Xiao Zhu2
Expert 3215 points
Part Number: REF3025

Hello Team

Could you help explain the difference between 3v input step response and 5v input step response?

1) Rise time 3V input is longer than 5V?

2) the rise wave have s step, why? 5v input, output voltage have a slow down

  • 0
    Guru 140200 points
    Hi Xiao,

    voltage references are no voltage regulators and can behave a bit strange during power-up. Yes, there's a difference with different input step voltages.

    Maybe this thread can help?

    e2e.ti.com/.../2400582

    Kai
  • 0 in reply to kai klaas69
    TI__Expert 3215 points
    Hello kai
    Could you help give more detail information about it?
  • 0 in reply to Xiao Zhu2
    Guru 140200 points
    Hi Xiao,

    I don't have more information. The only I can say is that the output voltage peak dissapears when an output cap of more than 2µ2/X7R/0805 is added. See again the given link.

    Kai
  • 0
    TI__Mastermind 19370 points

    Hi Xiao Zhu,

    The start up response of voltage references varies on the internal architecture. The step response you see on start-up is dependent on many factors such as the internal VREF ramp up and internal amplifier response as there usually needs to be certain voltage/current thresholds to be met as the device ramps up. Due to this the 3V and 5V Win for this particular device have different response rates based on how the input circuitry handles the higher voltage. Keep in mind these are typical graphs and there can be lot to lot variance.

    In the 5V Vin, like Kai said, you can minimize the voltage spike and smooth out the output response by having a capacitive load.

    -Marcoo