Datasheet

EN = 2 V / div
Time = 2 msec / div
V = 1 V / div
OUT
PWRGD = 5 V / div
V = 5 V / div
IN
EN = 2 V / div
Time = 2 msec / div
V = 1 V / div
OUT
PWRGD = 5 V / div
V = 5 V / div
IN
www.ti.com Test Setup and Results
2.9 Powering Up
Figure 9 and Figure 10 show the start-up waveforms for the TPS54519EVM-037. In Figure 9, the output
voltage ramps up as soon as the input voltage reaches the UVLO threshold as set by the R
1
and R
2
resistor divider network. In Figure 10, the input voltage is initially applied and the output is inhibited by
using a jumper at JP1 to tie EN to GND. When the jumper is removed, EN is released. When the EN
voltage reaches the enable-threshold voltage, the start-up sequence begins and the output voltage ramps
up to the externally set value of 1.8 V. The input voltage for these plots is 5 V and the load is 1Ω.
Figure 9. TPS54519EVM-037 Start-Up Relative to V
IN
Figure 10. TPS54519EVM-037 Start-Up Relative to Enable
9
SLVU523–September 2011 TPS54519EVM-037, 5-A, SWIFT™ Regulator— Evaluation Module
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