FPF2125 Fairchild Semiconductor, FPF2125 Datasheet - Page 10

• Manufacturer Part Number: FPF2125
• Description: IC LOAD SWITCH ADVANCED SOT23
• Manufacturer: Fairchild Semiconductor
• Series: IntelliMax™r
• Type: High Side Switchr

Specifications of FPF2125

• Number Of Outputs: 1
• Rds (on): 160 mOhm
• Internal Switch(s): Yes
• Current Limit: Adjustable
• Voltage - Input: 1.8 ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-5, SC-74A, SOT-25
• Power Switch Family: FPF2125
• Input Voltage: 1.8 to 5.5V
• Power Switch On Resistance: 125mOhm
• Output Current: 600mA
• Mounting: Surface Mount
• Package Type: SOT-23
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Pin Count: 5
• Power Dissipation: 667mW
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: FPF2125

FPF2123-FPF2125 Rev. F
Application Information
Typical Application
Setting Current Limit
The FPF2123, FPF2124, and FPF2125 have a current limit
which is set with an external resistor connected between ISET
and GND. This resistor is selected by using the following
equation,
The table below can also be used to select R
application would be the 500mA current that is required by a
single USB port. Using the table below an appropriate selection
for the R
port load could draw 570mA, but not more than 950mA.
Likewise for a dual port system, an R
deliver at least 1120mA and never more than 1860mA.
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
capacitance or a short-circuit, a capacitor needs to be placed
between V
placed close to the V
further reduce the voltage drop experienced as the switch is
turned on into a large capacitive load.
Output Capacitor
A 0.1 F capacitor, C
GND. This capacitor will prevent parasitic board inductances
from forcing V
FPF2123 and FPF2124, the total output capacitance needs to
be kept below a maximum value, C
from registering an over-current condition and turning-off the
switch. The maximum output capacitance can be determined
from the following formula,
Battery
5.5V
SET
IN
R
and GND. A 4.7 F ceramic capacitor, C
resistor would be 604 . This will ensure that the
OUT
C
SET
OU T
is in Ohms and that of I
below GND when the switch turns-off. For the
(
max
IN
OUT
pin. A higher value of C
)
, should be placed between V
R
=
SET
I
---------------------------------------------------------------- -
C1=4.7 F
LIM
=
(
min
460
--------- -
I
LIM
OFF ON
OUT(max)
) t
×
V
SET
IN
BLANK
of 340
LIM
5.5V MAX
, to prevent the part
(
min
is Amps
IN
)
can be used to
SET
would always
IN
. A typical
, must be
OUT
V
ON
FPF2123- FPF2125
IN
and
10
GND
Current Limit Various R
Power Dissipation
During normal operation as a switch, the power dissipated in the
part will depend upon the level at which the current limit is set.
The maximum allowed setting for the current limit is 1.5A and
this will result in a typical power dissipation of,
If the part goes into current limit the maximum power dissipation
will occur when the output is shorted to ground. For the
FPF2123 the power dissipation will scale by the Auto-Restart
Time, t
that the maximum power dissipated is,
P max
(
R
1070
1300
1910
3090
309
340
374
412
453
499
549
576
604
732
887
[ ]
SET
RESTART
)
=
=
-------------------
80
-------------------------------------------------------------------------------- -
t
V
RESTART
ISET
P
OUT
20
+
=
20
, and the Over Current Blanking Time, t
Min. Current
(
I
LIM
×
t
(
BL ANK
5.5
1010
min
Limit
[mA]
1120
R
920
840
760
690
630
600
570
470
390
320
260
180
110
)
2
SET
×
×
)
R
(
+
1.5
max
ON
t
BLANK
=
=
)
(
1.65W
1.5
C2=0.1 F
(
Typ. Current
SET
max
)
2
×
1490
1350
1230
1010
Limit
1120
[mA]
920
840
800
760
630
520
430
350
240
150
)
0.125
Values
×
V
IN
(
=
max
281mW
)
Max. Current
×
www.fairchildsemi.com
I
LIM
Limit
1860
1690
1540
1400
1270
1150
1050
1000
[mA]
950
790
650
540
440
300
190
(
R2=110
max
BLANK
)
, so
(4)