LTM8021

12

8021fb

APPLICATIONS INFORMATION

High Temperature Considerations

The die temperature of the LTM8021 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 LTM8021. To estimate the junction temperature, ap-

proximate the power dissipation within the LTM8021 by

applying the typical efficiency stated in this datasheet to

the desired output power, or, if one has an actual module,

by taking a power measurement. Then, calculate the tem-

perature rise of the LTM8021 junction above the surface

of the printed circuit board by multiplying the module’s

power dissipation by the thermal resistance. The actual

thermal resistance of the LTM8021 to the printed circuit

board depends on the layout of the circuit board, but the

thermal resistance given on page 2, which is based upon

Finally, be aware that at high ambient temperatures the

internal Schottky diode will have significant leakage current

(see the Typical Performance Characteristics) increasing

the quiescent current of the LTM8021.

+

LTM8021

4.7μF

CLOSING SWITCH

SIMULATES HOT PLUG

(5a)

(5b)

LOW

IMPEDANCE

ENERGIZED

24V SUPPLY

STRAY

INDUCTANCE

DUE TO 6 FEET

(2 METERS) OF

TWISTED PAIR

+

LTM8021

4.7μF

0.1μF

0.7Ω

(5c)

+

LTM8021

4.7μF

22μF

AI.EI.

+

20V/DIV

10A/DIV

20μs/DIV

DANGER

ABSOLUTE MAXIMUM RATING

20V/DIV

10A/DIV

20μs/DIV

8021 F05

20V/DIV

10A/DIV

20μs/DIV

Figure 5. Ensures Reliable Operation When the LTM8021 is Connected to a Live Supply