The oscilloscope screenshot in Figure 4-8 shows start-up to the no-load condition. Note that the glitch at the output of the buck converter happens when the SN6505-Q1 starts switching. Figure 4-9 illustrates how soft-start (SN6505B-Q1) improves this behavior. Both of the waveforms are taken using a Scope Rider handheld oscilloscope with isolated channels.

CH1 - V_IN, CH2 - V_out-bck, CH3 - V_OUT1, CH4 - V_OUT2

Figure 4-8 Start-up to No-Load Condition

CH1 - V_IN, CH2 - V_out-bck, CH3 - V_OUT1, CH4 - V_OUT2

Figure 4-9 Start-up to 2 × 150-Ω Load