LTM8032 Datasheet, PDF (14/20 Pages) Linear Technology – Ultralow Noise EMC Compliant 36V, 2A DC/DC μModule

LTM8032
APPLICATIONS INFORMATION
CLOSING SWITCH
SIMULATES HOT PLUG
I_IN
LTM8032
V_IN
+
4.7μF
V_IN
20V/DIV
DANGER
RINGING V_IN MAY EXCEED
ABSOLUTE MAXIMUM RATING
LOW
IMPEDANCE
ENERGIZED
24V SUPPLY
STRAY
INDUCTANCE
DUE TO 6 FEET
(2 METERS) OF
TWISTED PAIR
I_IN
10A/DIV
(5a)
0.7Ω
LTM8032
V_IN
V_IN
20V/DIV
+
0.1μF
4.7μF
I_IN
10A/DIV
20μs/DIV
(5b)
20μs/DIV
+
22μF ⁺
35V
AI.EI.
FIN
LTM8032
V_IN
4.7μF
V_IN
20V/DIV
I_IN
10A/DIV
(5c)
20μs/DIV
8032 F05
Figure 5. A Well Chosen Input Network Prevents Input Voltage Overshoot and Ensures
Reliable Operation When the LTM8032 is Hot-Plugged to a Live Supply
The die temperature of the LTM8032 must be lower than
the maximum rating of 125°C, so care should be taken
in the layout of the circuit to ensure good heat sinking
of the LTM8032. To estimate the junction temperature,
approximate the power dissipation within the LTM8032 by
applying the typical efficiency stated in this data sheet to
the desired output power, or, if you have an actual module,
by taking a power measurement. Then calculate the tem-
perature rise of the LTM8032 junction above the surface
of the printed circuit board by multiplying the module’s
power dissipation by the thermal resistance. The actual
14
thermal resistance of the LTM8032 to the printed circuit
board depends upon the layout of the circuit board, but
the thermal resistance given in the Pin Configuration,
as well as the internal temperature rise curves given in
the Typical Performance Characteristics section, can be
used a guide. Both the thermal resistance and internal
temperature rise curves are based upon a 36cm² 4-layer
FR4 PC board.
Finally, be aware that at high ambient temperatures the
internal Schottky diode will have significant leakage current,
increasing the input quiescent current of the LTM8032.
8032fa