B) If the load powered by the LM25069 hot swap circuit has
inductive characteristics, a Schottky diode is required across
the LM25069’s output, along with some load capacitance.
The capacitance and the diode are necessary to limit the
negative excursion at the OUT pin when the load current is
shut off. If the OUT pin transitions more than 0.3V negative
the LM25069 will internally reset, interfering with the latch-off
feature of the LM25069-1, or the restart cycle of the
LM25069-2. See Figure 17.
System Considerations
A) Continued proper operation of the LM25069 hot swap cir-
cuit requires capacitance be present on the supply side of the
connector into which the hot swap circuit is plugged in, as
depicted in Figure 2. The capacitor in the “Live Power Source”
section is necessary to absorb the transient generated when-
ever the hot swap circuit shuts off the load current. If the
capacitance is not present, inductance in the supply lines will
generate a voltage transient at shut-off which can exceed the
absolute maximum rating of the LM25069, resulting in its de-
struction.
30086754
FIGURE 17. Output Diode Required for Inductive Loads
21
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