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

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 1

Ω.

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

Submit Documentation Feedback

Copyright

© 2011, Texas Instruments Incorporated