LP3972 Buck output transient load response

Hi Subhash,

If the DS typical plots does not have what you need please consult the LP3907 DS which shows better waveforms using the scope native plots.  Depends on one's setup and edge rate they do makes a real big differnece.  Improved setup in recent years showed cleaner transient steady and  spikes.   What is you concern? On LDO ? buck?  I can give you typical numbers that is (<10mVpp for bucks and ldos) but that depends on how I take it and where I capture.  It may be different on you product PCB (usually) vs my test boards and probes. See the following article to familiarize with transient response measurments.  If you have any question let me know.  What is you pk over shoot or under should budget?  They are usually smaller that you see because when you probe you add inductance which makes it bigger and how fast is your application pulls current out of the regulators?  If your load has lots of bypass capacitance, the chances are it will roll out the peaking spiks significantly because of the slower ramping result   (Beyond 10us edge rates you wil be seeing lower peaking amplitude.) 

Thank you,

Kern

http://www.edn.com/design/power-management/4375871/3/High-performance-load--and-line-transient-test-jigs-for-mobile-regulators

www.ti.com/lit/pdf/snoa895