FPF2108NL Fairchild Semiconductor, FPF2108NL Datasheet - Page 10

• Manufacturer Part Number: FPF2108NL
• Manufacturer: Fairchild Semiconductor

Specifications of FPF2108NL

• Switch Type: Low Side
• Power Switch Family: FPF2108
• Input Voltage: 1.8 to 5.5V
• Output Current: 400mA
• Number Of Outputs: Single
• Mounting: Surface Mount
• Package Type: SOT-23
• Operating Temperature (min): -40C
• Operating Temperature (max): 125C
• Operating Temperature Classification: Automotive
• Pin Count: 5
• Power Dissipation: 667mW
• Lead Free Status / Rohs Status: Compliant

FPF2108-FPF2110 Rev. E
Application Information
Typical Application
Input Capacitor
To limit the voltage drop on the input supply caused by transient
in-rush currents when the switch turns-on into a discharged load
capacitor or a short-circuit, a capacitor needs to be placed
between V
be placed close to the V
used to further reduce the voltage drop experienced as the
switch is turned on into a large capacitive load.
Output Capacitor
A 0.1µF capacitor C
GND. This capacitor will prevent parasitic board inductances
from forcing V
Power Dissipation
During normal operation as a switch, the power dissipation is
small and has little effect on the operating temperature of the
part. The parts with the higher current limits will dissipate the
most power and that will only typically be,
When in current limit the maximum power dissipation will occur
when the output is shorted to ground. A short on the output will
cause the part to operate in a constant current state until the
thermal shutdown activates. It will then cycle in and out of
thermal shutdown so long as the ON pin is active and the short
is present.
Board Layout
For best performance, all traces should be as short as possible.
To be most effective, the input and output capacitors should be
placed close to the device to minimize the effects that parasitic
trace inductances may have on normal and short-circuit
operation. Using wide traces for V
minimize parasitic electrical effects along with minimizing the
case to ambient thermal impedance.
Battery
1.8V-5.5V
P
=
(I
IN
LIM
and GND. A 4.7µF ceramic capacitor, C
OUT
)
2
∗
below GND when the switch turns-off.
R
OUT
DS
, should be placed between V
=
C1 = 4.7µF
IN
(0.8)
pin. A higher value of C
OFF ON
2
∗
IN
0.125
, V
OUT
=
and GND will help
80mW
OUT
IN
IN
V
ON
FPF2108 - FPF2110
can be
, must
IN
and
10
GND
FLAGB
V
OUT
R1 = 100KΩ
C2 = 0.1µF
LOAD
www.fairchildsemi.com
R2 = 499Ω