Datasheet

VIN
GND
GND
LIVE
POWER SOURCE
OUT
Q1
PLUG-IN BOARD
R
S
V
SYS
V
OUT
+12V
C
L
Inductive
Load
LM25069
SENSE
Q1
SENSE
VIN
UVLO
OVLO
GND
GATE
OUT
PGD
PWR
TIMER
R1
R2
R3
To
Load
LM25069
R
S
CARD EDGE
CONNECTOR
PLUG-IN CARD
V
SYS
GND
LM25069
SNVS607E –FEBRUARY 2011–REVISED MARCH 2013 www.ti.com
Figure 36. Recommended Board Connector Design
System Considerations
a. Continued proper operation of the LM25069 hot swap circuit requires capacitance be present on the supply
side of the connector into which the hot swap circuit is plugged in, as depicted in Figure 22. The capacitor in
the “Live Power Source” section is necessary to absorb the transient generated whenever 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
destruction.
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 37.
Figure 37. Output Diode Required for Inductive Loads
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Product Folder Links: LM25069