This measurement shows the behavior of the Power Management Integrated Circuit (PMIC) when the system reaches the steady state.
Maximum load is usually used in this test. Monitoring both input and output values shows the performance of the system. It is a good idea to run the same test with the maximum load current of the application for some time, to see if the PMIC fits the application.
To capture the ripple, set both probes of the oscilloscope to AC coupling and adjust Trigger. Capture waveforms on both CH1 and CH2. Measuring peak-to-peak voltage values on both shows the PMIC voltage ripple.
To get correct measurements, the GND lead of the probe should be as short as possible. It is also common to limit the scope bandwidth to 20 MHz. In real applications, it is recommended to perform these measurements at all values of input and output voltages and real loads to check that the voltage regulator does not introduce unexpected noise to the system.