Datasheet

Start-Up
2-17
Test Setup and Results
2.10 Start-Up
The start-up voltage waveform of the TPS54x72EVM−222 is shown in
Figure 2−24, Figure 2−25, and Figure 2−26. There is approximately a 3.6-ms
delay after the input voltage rises above the 2.9 V (3.8 V for the TPS54872)
startup voltage threshold until the output voltage begins to ramp up to the final
value of 1.25 V. The output voltage tracks the greater of the internal and
external slow start voltages, accounting for the change in ramp rates.
Figure 2−24. Measured Start-Up Waveform, TPS54672
V
I
1 V/div
Time Scale 2.5 ms/div
V
O
500 mV/div
Figure 2−25. Measured Start-Up Waveform, TPS54872
V
I
2 V/div
Time Scale 2.5 ms/div
V
O
500 mV/div