FPF2225 Fairchild Semiconductor, FPF2225 Datasheet - Page 10

• Manufacturer Part Number: FPF2225
• Description: IC LOAD SWITCH MICROFET6
• Manufacturer: Fairchild Semiconductor
• Type: High Side Switchr

Specifications of FPF2225

• Number Of Outputs: 1
• Rds (on): 185 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: 6-MLP, 6-MicroFET™
• Input Voltage: 1.8 to 5.5V
• Power Switch On Resistance: 230mOhm
• Mounting: Surface Mount
• Package Type: MicroFET
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Pin Count: 6
• Power Dissipation: 1.2W
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: FPF2225TR

FPF2223-FPF2225 Rev. C
Application Information
Setting Current Limit
The FPF2223, FPF2224, and FPF2225 have adjustable high
precision current limit which is set with an external resistor
connected between ISET and GND. Please see the layout
recommendation section of the application note for the
recommended R
using the following equation:
For a particular I
below formula:
FPF222X family has 5% precision at higher load current. The
I
using Figure 23 (I
The table and figure below can be used to select R
LIM (Max)
I
LIM (Typ)
R
R
36.0
37.5
39.0
40.2
42.2
44.2
49.0
51.1
54.9
61.9
69.8
80.9
[k ]
Tolerance (%) = 100 *
I
SET
SET
LIM (Max)
(K ) =
and tolerance of current limit value can be determined
(mA) =
Min. Current
Limit [mA]
= I
627.0
600.9
576.2
557.7
529.3
503.3
449.5
429.1
396.0
345.3
299.8
250.0
Table 1: R
SET
LIM (Typ) +
I
LIM
LIM
LIM (Min)
R
(min) value, R
layout. The R
SET
vs R
23764
SET
(K )
SET
Typ. Current
(mA) + 25 +
Limit [mA]
I
LIM (Typ)
23764
660.0
633.7
609.3
591.1
563.1
537.6
485.0
465.0
432.9
383.9
340.5
293.7
Selection Guide
) and the following formula:
I
LIM (Typ)
SET
SET
* Tolerance (%)
100
I
LIM (Typ)
resistance is selected by
can be calculated from
I
Max. Current
LIM (Min)
- I
Limit [mA]
LIM (Min)
4700
693.0
666.5
642.5
624.5
597.0
572.0
520.4
501.0
469.7
422.5
381.1
337.5
(mA)
SET
:
10.1
14.9
11.9
[%]
5.0
5.2
5.4
5.7
6.0
6.4
7.3
7.7
8.5
Tol
10
Input Capacitor
To limit the voltage drop on the input supply caused by transient
in-rush currents when the switch is turned on into a discharged
load capacitor or a short-circuit, a capacitor is recommended to
be placed between V
placed close to the pins is usually sufficient. Higher values of
C
Output Capacitor
A 0.1uF capacitor C
GND. This capacitor will prevent parasitic board inductances
from forcing V
FPF2223 and FPF2224, the total output capacitance needs to
be kept below a maximum value, C
part from registering an over-current condition and turning-off
the switch. The maximum output capacitance can be
determined from the following formula:
Power Dissipation
During normal on-state operation, the power dissipated in the
device will depend upon the level at which the current limit is
set. The maximum allowed setting for the current limit is 625mA
and will result in a power dissipation of:
If the part goes into current limit, maximum power dissipation
will occur when the output is shorted to ground. For the
FPF2223, the power dissipation will be scaled by the Auto-
Restart Time, t
t
BLANK
IN
C
P = (I
P
720
660
600
540
480
420
360
300
240
can be used to further reduce the voltage drop.
OUT (Max)
(Max)
. Therefore, the maximum power dissipated is:
34
LIM
=
)
=
2
* R
=
OUT
t
BLANK
30 + 450
42
RSTRT
DS
below GND when the switch turns-off. For the
30
t
I
= (0.625)
BLANK
LIM (Max)
Figure 23. I
OUT
IN
+ t
, and the Over Current Blanking Time,
and GND. A 1uF ceramic capacitor, C
, should be placed between V
RSTRT
50
* 5.5 * 0.693 = 0.238W
2
* t
V
R
* 0.165 = 64mW
IN
BLANK (Min)
SET
LIM
(KOhms)
* V
58
vs R
IN (Max)
OUT
SET
(max), to prevent the
66
* I
LIM (Max)
www.fairchildsemi.com
74
Max
OUT
Typ
Min
and
IN
82
,