LTC4358

8

4358fa

APPLICATIONS INFORMATION

Figure 3. –12V Reverse Input Protection

LTC4358

GND

IN

DRAIN

OUT

C1

0.1μF

R1

100Ω

12V

5A

4358 F03

MMBD1205

In the event of an input short, parasitic inductance between

the input supply of the LTC4358 and the load bypass

increase. To preserve the fast turn-off time, local output

bypassing of 39μF or more is sufficient or a 100Ω, 0.1μF

in Figure 2a and Figure 2b.

Layout Considerations

The following advice should be considered when laying out

a printed circuit board for the LTC4358: The OUT pin should

Figure 2. Two Methods of Protecting Against Collapse

4358 F02

LTC4358

GND

IN

DRAIN

OUT

LTC4358

GND

IN

DRAIN

OUT

R1

100

C1

0.1 F

39 F

(a)

(b)

be connected as closely as possible to the EXPOSED PAD

(drain of the MOSFET) for good accuracy. Keep the traces

to the IN and DRAIN wide and short. The PCB traces as-

sociated with the power path through the MOSFET should

have low resistance. See Figure 4.

The DRAIN acts as a heatsink to remove the heat from the

device. For a single layer PCB with the DFN package, use

Figure 5 to determine the PCB area needed for a speci-

fied maximum current and ambient temperature. If using

a two sided PCB, the maximum current is increased by

10%. If the FE package is used, the maximum current is

increased by 4%.