Datasheet

Waveforms

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Figure 3. Efficiency vs. Output Current and VIN

5 Waveforms

When power is applied to the LM25037 evaluation board a certain sequence of events occurs. Soft-start

capacitor values and other components ensure a linear increase in output voltage for a short time until the

feedback loop can stabilize without an overshoot. Figure 4 shows the output voltage during a typical start-

up with a 24V input and a load of 10A. There is no overshoot during startup. It is strongly recommended to

use a resistor load instead of an electronic load, while capturing soft-start data as electronic loads tend to

have small idiosyncrasies such as not providing load resistance till the output reaches certain voltage.

This occasionally causes a transient during start-up.

Conditions:

Input Voltage = 24VDC

Output Current = 10A

Trace:

Output Voltage, Volts/div = 1V

Horizontal Resolution = 0.5 ms/div

Figure 4. Soft Start

Figure 5 shows typical output ripple seen directly across the output capacitor, for an input voltage of 24V

and a load of 10A. This waveform is typical of most loads and input voltages.

AN-1861 LM25037 Evaluation Board SNVA352C–July 2008–Revised May 2013

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