FPF1203 Fairchild Semiconductor, FPF1203 Datasheet - Page 8

• Manufacturer Part Number: FPF1203
• Manufacturer: Fairchild Semiconductor

© 2011 Fairchild Semiconductor Corporation
FPF1203 / FPF1204 • Rev. 1.1.4
Operation and Application Description
The FPF1203/FPF1204 is low-R
switch with controlled turn-on. The core of each device
is a 55m P-channel MOSFET and controller capable
of functioning over a wide input operating range of 1.2 to
5.5V. The ON pin, an active-HIGH GIOP / CMOS-
compatible input, controls the state of the switch.
The FPF1204 contains a 65 on-chip load resistor for
quick output discharge when the switch is turned off.
Input Capacitor
To limit the voltage drop on the input supply caused by
transient inrush current when the switch turns on into a
discharged load capacitor or short-circuit, a capacitor
must be placed between the V
ceramic capacitor, C
usually sufficient. Higher-value C
reduce the voltage drop in higher-current applications.
Output Capacitor
A 0.1µF capacitor, C
V
board inductance from forcing V
OUT
and GND pins. This capacitor prevents parasitic
Figure 21. Typical Application
OUT
IN
, placed close to the pins is
, should be placed between the
IN
OUT
and GND pins. A 1µF
IN
ON
below GND when
can be used to
P-channel load
the switch is on. C
recommended. C
exceed V
could result in current flow through the body diode from
V
Board Layout
For best performance, traces should be as short as
possible. To be most effective, input and output
capacitors should be placed close to the device to
minimize the effect of parasitic trace inductance on
normal and short-circuit operation. Using wide traces or
large copper planes for all pins (VIN, VOUT, ON, and
GND) minimizes the parasitic electrical effects and the
case-ambient thermal impedance. However, the VOUT
pin should not connect directly to the battery source due
to the discharge mechanism of the load switch.
V OUT
OUT
8
V OUT
V ON
to V
IN
IN
.
50%
10%
when the system supply is removed. This
t
Figure 22. Timing Diagram
DON
t
R
OUT
10%
90%
greater than C
IN
3.3V
greater than C
50%
IN
90%
can cause V
t
DOFF
OUT
t
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F
90%
is highly
10%
OUT
to