Datasheet

7 www.fairchildsemi.com
FPF1003-FPF1004 Rev. H
FPF1003-FPF1004 IntelliMAX™ Advanced Load Management Products
Description of Operation
The FPF1003 & FPF1004 are low R
DS(ON)
P-Channel load
switches with controlled turn-on. The core of each device is a
30mΩ P-Channel MOSFET and a controller capable of
functioning over a wide input operating range of 1.2-5.5V.
Switch control is by a logic input (ON) capable of interfacing
directly with low voltage control signal. In FPF1004, 120Ω
on-chip load resistor is added for output quick discharge when
switch is turned off.
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 short-circuit, a capacitor needs to be placed
between V
IN
and GND. A 1µF ceramic capacitor, C
IN
, placed
close to the pins is usually sufficient. Higher values of C
IN
can
be used to further reduce the voltage drop.
Output Capacitor
A 0.1µF capacitor, C
OUT
, should be placed between V
OUT
and
GND. This capacitor will prevent parasitic board inductance
from forcing V
OUT
below GND when the switch turns-off. Due to
the integral body diode in the PMOS switch, a C
IN
greater than
C
OUT
is highly recommended. A C
OUT
greater than C
IN
can
cause V
OUT
to exceed V
IN
when the system supply is removed.
This could result in current flow through the body diode from
V
OUT
to V
IN
.
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
IN
, V
OUT
and GND will help
minimize the parasitic electrical effects along with minimizing
the case to ambient thermal impedance.
OFF ON ON
V
IN
GND
FPF1003/4
V
OUT
TO LOAD
-
Battery
1.2V-5.5V
C1 = 1µF
C2 = 0.1µF
R1 = 499Ω