LT3684
APPLICATIONS INFORMATION
CLOSING SWITCH
DANGER
SIMULATES HOT PLUG
V
IN
I
IN
20V/DIV
V
IN
RINGING V MAY EXCEED
LT3684
4.7µF
IN
ABSOLUTE MAXIMUM RATING
+
I
IN
LOW
STRAY
10A/DIV
IMPEDANCE
ENERGIZED
24V SUPPLY
INDUCTANCE
DUE TO 6 FEET
(2 METERS) OF
TWISTED PAIR
20µs/DIV
(9a)
0.7Ω
V
IN
20V/DIV
LT3684
4.7µF
+
0.1µF
I
IN
10A/DIV
20µs/DIV
(9b)
V
IN
20V/DIV
LT3684
4.7µF
+
+
22µF
35V
AI.EI.
I
IN
10A/DIV
3684 F09
20µs/DIV
(9c)
Figure 9. A Well Chosen Input Network Prevents Input Voltage Overshoot and
Ensures Reliable Operation when the LT3684 is Connected to a Live Supply
maximum load current should be derated as the ambient
Other Linear Technology Publications
temperature approaches 125°C.
Application Notes 19, 35 and 44 contain more detailed
descriptions and design information for buck regulators
and other switching regulators. The LT1376 data sheet
has a more extensive discussion of output ripple, loop
compensation and stability testing. Design Note 100
shows how to generate a bipolar output supply using a
buck regulator.
Power dissipation within the LT3684 can be estimated by
calculatingthetotalpowerlossfromanefficiencymeasure-
ment and subtracting the catch diode loss and inductor
loss. The die temperature is calculated by multiplying the
LT3684 power dissipation by the thermal resistance from
junction to ambient.
3684f
18