Datasheet

2.8 Input Voltage Ripple
V
IN
PH
2.9 Powering Up
V
IN
V
OUT
Test Setup and Results www.ti.com
The TPS54233EVM-373 input voltage ripple is shown in Figure 8 . The output current is the rated full load
of 2 A. Voltage is measured directly across the input capacitors.
Figure 8. TPS54233EVM-373 Input Ripple
The start-up waveforms are shown in Figure 9 and Figure 10 . In Figure 9 , the top trace shows V
IN
, and the
bottom trace shows V
OUT
. In Figure 10 , the top trace shows EN (enable) whereas the bottom trace shows
V
OUT
. In Figure 10 , the input voltage is initially applied and the output is inhibited by using a jumper at J2
to tie EN to GND. When the jumper is removed, EN is released. When the EN voltage reaches the
enable-threshold voltage of 1.25 V, the start-up sequence begins and the internal reference voltage begins
to ramp up at the internally set rate toward 0.8 V and the output voltage ramps up to the externally set
value of 3.3 V. The input voltage for these plots is 15 V and there is no load.
Figure 9. TPS54233EVM-373 Start-Up Relative to V
IN
8 TPS54233EVM-373 2-A, SWIFT™ Regulator Evaluation Module SLVU264 – November 2008
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