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REG104: REG104 3.3V

saikumar A
Prodigy 80 points
Part Number: REG104

Hi Team,

I need to verify the Load and Line transient response of the part REG104 3.3V.

In datasheet, they given spec as below

as I have seen, the load transient has spec of around 500mV overshoot and 650mV undershoot for 0uF cap, and 200mV overshoot and 300mV undershoot for 10uF cap, but I got the result for 0uF but getting same result for 10uF also, even If I increase the cap to 20uF also, getting same response as 0uF.

Also, for Line transient response, I'm not getting the spec for both 0 and 10uF cap, kindly help to resolve as I need to verify transient to make sure it will not impact on future.

  • 0
    TI__Mastermind 42355 points

    Hi Saikumar,

    Do you have any waveforms to share of your testing? What was the load step spec that you used? The load transient in the datasheet is approximately 500mA/us and starts at 10mA - is this what you did? If you started at 0A the load transient will be much worse.

    Is there any possibility that I can steer you towards a better device? This device has pretty poor performance and is quite expensive so I'm sure I could find a more suitable device for you if you aren't too far into the design phase. 

    Regards,

    Nick

  • 0 in reply to Nick Butts
    Prodigy 80 points

    Hi Nick,

    Thanks for your response,

    I used the same spec as mentioned like 10mA to 1A.

    Please find the image below for captured waveform

    Thanks,

    Saikumar A

  • 0 in reply to saikumar A
    TI__Mastermind 42355 points

    Hi Saikumar,

    Your waveforms have me questioning whether the time scale on the waveforms in the datasheet is accurate because the datasheet plots show that the device recovers from the transient in a few microseconds, which is extremely fast for modern devices, and your waveform shows that the device recovers on a time scale closer to 1ms. Unfortunately this is an old legacy device and we have very limited documentation for it, so the information that is in the datasheet is the only technical information that we have for it. 

    Have you tried slowing down the pulse frequency? I wonder if there are extra temperature effects on the output capacitor and the device itself since this is also a pretty large transient. What is the rating of the output capacitor?

    Can you please address my question on the possibility of using a newer device? There are likely cheaper devices that would work for this that are manufactured on a newer technology node, and we will have much better documentation for them so we can provide much better support.

    Regards,

    Nick