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FPF2223-FPF2225
tm
Integrated Load Switch with Adjustable High Precision Current Limit
Features
General Description
1.8 to 5.5V Input Voltage Range
Typical RDS(ON) = 140m
Typical RDS(ON) = 160m
The FPF2223-FPF2225 are low RDS(ON) P-Channel MOSFET
load switches with high precision current limit value. The input
voltage range operates from 1.8V to 5.5V to fulfill today's Ultra
Portable Device's supply requirement. Switch control is by a
logic input (ON) capable of interfacing directly with low voltage
control signal. On-chip pull-down is available for output quick
discharge when switch is turned off.
@ VIN = 5.5V
@ VIN = 3.3V
250-625mA (min) Adjustable Current Limit
5% Current Limit Tolerance @ 625mA (min)
72
(typ) Output Discharge Resistance
ESD Protected, Above 8kV HBM and 2kV CDM
For the FPF2224, if the constant current condition still persists
after 30ms, these parts will shut off the switch and pull the fault
signal pin (FLAGB) low. The FPF2223 has an auto-restart
feature, which will turn the switch on again after 450mS if the
ON pin is still active. The FPF2224 do not have this auto-restart
feature so the switch will remain off until the ON pin is cycled.
For the FPF2225, a current limit condition will immediately pull
the fault signal pin low and the part will remain in the constantcurrent mode until the switch current falls below the current
limit. For the FPF2223 through FPF2225, the current limit is set
by an external resistor and the minimum current limit is 250mA.
Applications
PDAs
Cell Phones
GPS Devices
MP3 Players
Digital Cameras
Peripheral Ports
Notebook Computer
Pin 1
BOTTOM
TOP
Ordering Information
Part
Current Limit
(mA)
Current Limit
Blanking Time
(mS)
Auto-Restart Time
(mS)
ON Pin
Activity
FPF2223
250-625
30
450
Active HI
FPF2224
250-625
30
NA
Active HI
FPF2225
250-625
NA
NA
Active HI
©2008 Fairchild Semiconductor Corporation
FPF2223-FPF2225 Rev. C
1
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FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
February 2009
TO LOAD
FPF2223/4/5
VOUT
VIN
FLAGB
OFF ON
ON
ISET
GND
Functional Block Diagram
VIN
UVLO
THERMAL
SHUTDOWN
CONTROL
LOGIC
ON
CURRENT
LIMIT
VOUT
ISET
Output Discharge
FLAGB
GND
FPF2223-FPF2225 Rev. C
2
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FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
Typical Application Circuit
ON 6
1 ISET
GND 5
2 VIN
FLAGB 4
3 VOUT
MicroFET 2x2 6L
(BOTTOMVIEW)
Pin Description
Pin
Name
1
ISET
Current Limit Set Input : A resistor from ISET to ground sets the current limit for the switch
Supply Input: Input to the power switch and the supply voltage for the IC
2
VIN
3
VOUT
4
FLAGB
5
GND
6
ON
Function
Switch Output: Output of the power switch
Fault Output: Active LO, open drain output which indicates an over current, supply
under voltage or over temperature state
Ground
ON/OFF Control Input
Absolute Maximum Ratings
Parameter
Min.
Max.
Unit
VIN, VOUT, ON, FLAGB TO GND
-0.3
6
V
ISET TO GND
-0.3
Power Dissipation @ TA = 25°C
Operating and Storage Junction Temperature
-65
Thermal Resistance, Junction to Ambient
Electrostatic Discharge Protection
0.3
V
1.2
W
125
°C
86
°C/W
HBM
8000
V
MM
400
V
CDM
2000
V
Recommended Operating Range
Parameter
Min.
Max.
Unit
VIN
1.8
5.5
V
Ambient Operating Temperature, TA
-40
85
°C
Electrical Characteristics
VIN = 1.8 to 5.5V, TA = -40 to +85°C unless otherwise noted. Typical values are at VIN = 3.3V and TA = 25°C.
Parameter
Symbol
Conditions
Min.
Typ.
Max.
Units
5.5
V
Basic Operation
Operating Voltage
VIN
Quiescent Current
IQ
VIN Shutdown Current
FPF2223-FPF2225 Rev. C
1.8
IOUT=0mA, VIN=VON=1.8V, RSET=36K
45
75
IOUT=0mA, VIN=VON=3.3V, RSET=36K
50
80
IOUT=0mA, VIN=VON=5.5V, RSET=36K
55
VON=0V, VIN=5.5V, VOUT=short to GND
3
A
95
2.5
A
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FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
Pin Configuration
Symbol
VOUT Shutdown Current
On-Resistance
Conditions
Min.
Typ.
Max.
Units
1
A
VIN=5.5V, IOUT=200mA, TA=25°C
140
185
VIN=3.3V, IOUT=200mA, TA=25°C
160
210
VIN=1.8V, IOUT=200mA, TA=25°C
230
300
72
105
VON=0V, VOUT=5.5V, VIN=short to GND
RON
VIN=3.3V, IOUT=200mA, TA=-40 to +80°C
Output Discharge Resistance
90
VIN=3.3V, VON=0V, IOUT=10mA
ON Input Logic High Voltage (ON)
VIH
ON Input Logic Low Voltage (OFF)
VIL
On Input Leakage
VIN=1.8V
0.8
VIN=5.5V
1.4
FLAGB Output Logic Low Voltage
FLAGB Output High Leakage
Current
265
V
VIN=1.8V
0.5
VIN=5.5V
1.0
VON = VIN or GND
m
-1
1
VIN=5.5V, ISINK=100 A
0.05
0.1
VIN=1.8V, ISINK=100 A
0.12
0.25
VIN=5.5V, Switch on
V
A
V
1
uA
693
mA
Protections
Current Limit
ILIM
Thermal Shutdown
Under Voltage Shutdown
UVLO
VIN=3.3V, VOUT = 3.0V, RSET=36K,
TA=25°C
627
660
Shutdown Threshold
140
Return from Shutdown
130
Hysteresis
10
VIN increasing
1.55
Under Voltage Shutdown Hysteresis
1.65
°C
1.75
V
50
mV
Dynamic
Turn On Time
tON
RL=500 , CL=0.001uF
70
S
Turn Off Time
tOFF
RL=500 , CL=0.001uF
600
nS
VOUT Rise Time
tRISE
RL=500 , CL=0.001uF
40
S
VOUT Fall Time
tFALL
RL=500 , CL=0.001uF
Over Current Blanking Time
tBLANK
FPF2223, FPF2224
15
30
60
mS
Auto-Restart Time
tRSTRT
FPF2223
225
450
900
mS
Current Limit Response Time
FPF2223-FPF2225 Rev. C
VIN = VON = 3.3V. Over-Current
Condition: RLOAD=VIN/(ILIMx4)
4
100
5
nS
S
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FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
Parameter
80
90
80
60
SUPPLY CURRENT (uA)
70
SUPPLY CURRENT (uA)
VON=VIN
VON = VIN
o
85 C
50
o
25 C
40
o
-40 C
30
VIN=3.3V
70
VIN=5.5V
60
50
VIN=1.8V
40
30
20
20
-40
10
1
2
3
4
5
6
-15
60
85
Figure 2. Quiescent Current vs. Temperature
1.6
1.4
1.4
VON SUPPLY VOLTAGE (V)
1.2
VIH
1.0
VIL
0.8
0.6
0.4
VIN=5.5V
1.2
1
VIN=3.3V
0.8
VIN=1.2V
0.6
0.4
0.2
-40
0.2
1
2
3
4
5
6
-15
10
35
60
85
TJ, JUNCTION TEMPERATURE (oC)
VIN, SUPPLY VOLTAGE (V)
Figure 3. VON vs. Input Voltage
Figure 4. VON High Voltage vs. Temperature
1.4
0.05
1.2
VIN=5.5V
1.0
0.04
ON PIN CURRENT (uA)
VON SUPPLY VOLTAGE (V)
35
o
Figure 1. Quiescent Current vs. Input Voltage
VON SUPPLY VOLTAGE (V)
10
TJ, JUNCTION TEMPERATURE ( C)
SUPPLY VOLTAGE (V)
VIN=3.3V
0.8
VIN=1.2V
0.6
0.4
0.03
0.02
VON = 5.5V
0.01
0.00
0.2
0.0
VON = 0V
-0.01
-40
-15
10
35
60
85
-40
o
10
35
60
85
TJ, JUNCTION TEMPERATURE ( C)
Figure 5. VON Low Voltage vs. Temperature
FPF2223-FPF2225 Rev. C
-15
o
TJ, JUNCTION TEMPERATURE ( C)
Figure 6. On Pin Current vs. Temperature
5
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FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
Typical Characteristics
700
700
690
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
800
600
500
400
300
200
100
RSET = 36K
680
670
660
VIN = 1.8V
650
VIN = 3.3V
640
VIN = 5.5V
630
0
0
1
2
3
4
5
620
-40
6
-15
35
60
85
TJ, JUNCTION TEMPERATURE ( C)
Figure 7. Current Limit vs. Output Voltage
Figure 8. Current Limit vs. Temperature
320
340
280
300
240
260
200
RON(mOhms)
RON(mOhms)
10
o
VIN-VOUT (V)
o
85 C
160
o
25 C
VIN=1.8V
220
VIN=3.3V
180
140
120
VIN=5.5V
o
-40 C
100
80
60
-40
40
1.5
2.5
3.5
4.5
5.5
-15
TON
TRISE
10
TOFF
1
35
60
o
VIN = 3.3V
RL = 500 Ohms
COUT = 0.11uF
10
TFALL
1
0.1
-40
85
-15
10
35
60
85
o
TJ, JUNCTION TEMPERATURE ( C)
TJ, JUNCTION TEMPERATURE ( C)
Figure 11. TOFF / TON vs. Temperature
FPF2223-FPF2225 Rev. C
85
100
VIN = 3.3V
RL = 500 Ohms
COUT = 0.11uF
100
10
60
Figure 10. RON vs. Temperature
RISE / FALL TIMES (uS)
TURN-ON/OFF TIMES (uS)
1000
-15
35
o
Figure 9. RON vs. Input Voltage
0.1
-40
10
TJ, JUNCTION TEMPERATURE ( C)
VIN, SUPPLY VOLTAGE(V)
Figure 12. TRISE / TFALL vs. Temperature
6
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FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
Typical Characteristics
1000
VIN
2V/DIV
TBLANK / TRESTART (mS)
TRESTART
IOUT
10mA/DIV
100
TBLANK
VON
2V/DIV
10
VIN=3.3V,
RL=500 ,
CIN=10uF,
RSET=36K
VOUT
2V/DIV
1
-40
-15
10
35
60
85
100 s/DIV
TJ, JUNCTION TEMPERATURE (oC)
Figure 13. TBLANK vs Temperature
Figure 14. Turn On Response
VDRV1
5V/DIV
VIN
2V/DIV
IOUT
10mA/DIV
IOUT
500mA/DIV
VON
2V/DIV
VFLAGB
2V/DIV
VOUT
2V/DIV
VIN=3.3V,
RL=500 ,
CIN=10uF,
RSET=36K
10ms/DIV
Figure 15. Turn Off Response
Figure 16. TBLANK Response
VON
2V/DIV
VIN=5V, CIN=10uF,
RL=100 ,COUT=1uF,
RSET=36K
IOUT
500mA/DIV
VIN=5V, CIN=10uF,
RL=100 ,COUT=1uF,
RSET=36K
VOUT
2V/DIV
500ns/DIV
VDRV1
5V/DIV
TBLANK
IOUT
10mA/DIV
VFLAGB
2V/DIV
VIN
2V/DIV
TRESTART
VOUT
2V/DIV
VOUT
2V/DIV
VIN=3.3V, CIN=10uF,
RL=1.2 ,COUT=10uF,
RSET=36K
100 s/DIV
100ms/DIV
Figure 17. TRESTART Response
Figure 18. Current Limit Response
(Output is loaded with 1.2 resistor and COUT=10 F)
Note1: VDRV signal drives the gate of a NMOS transistor. The NMOS transistor is in series with a 5 resistor and is connected to the
output of device. By turning on the transistor, the 5 resistor is loaded to the output and forces the device to go into overcurrent
condition.
FPF2223-FPF2225 Rev. C
7
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FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
Typical Characteristics
VON
2V/DIV
VIN=5V, CIN=10uF,
COUT=100uF,
RL=1.2 ,
RSET=36K
VON
2V/DIV
IOUT
500mA/DIV
IOUT
500mA/DIV
VIN
5V/DIV
VIN
5V/DIV
VOUT
2V/DIV
VOUT
5V/DIV
500 s/DIV
2ms/DIV
Figure 19. Current Limit Response
(Output is loaded with 1.2 resistor and COUT=100 F)
Figure 20. Current Limit and Output Discharge Response
(Device turns on and off into large capacitive load COUT=100F)
VIN=VON
2V/DIV
VON
2V/DIV
IOUT
500mA/DIV
VOUT
2V/DIV
VIN=3.3V, CIN=10uF,
RL=100 ,COUT=1uF,
RSET=36K
IOUT
5A/DIV
VIN=VON=3.3V,
CIN=10uF, RL=1.2 ,
COUT=1uF,
RSET=36K
VOUT
2V/DIV
20 s/DIV
50 s/DIV
Figure 21. Current Limit Response
(Switch is powered into a short - Input and
enable pin are tied together)
FPF2223-FPF2225 Rev. C
VIN=5V, CIN=10uF,
RL=1.2 , COUT=100uF,
RSET=36K
Figure 22. Short Circuit Response Time
(Output shorted to GND while the switch is in normal operation)
8
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FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
Typical Characteristics
Undervoltage Lockout (UVLO)
The FPF2223, FPF2224, and FPF2225 are state of the art
Adjustable High Precision Current Limit switches that protect
systems and loads which can be damaged or disrupted by the
application of high currents. The core of each device is a 0.16
P-channel MOSFET and a controller capable of functioning over
an input operating range of 1.8- 5.5V. The controller protects or
offers current limiting, UVLO(undervoltage lockout) and thermal
shutdown protection. The current limit is adjustable from 250mA
to 625mA through the selection of an external resistor.
The undervoltage lockout turns-off the switch if the input voltage
drops below the undervoltage lockout threshold. With the ON
pin active the input voltage rising above the undervoltage
lockout threshold will cause a controlled turn-on of the switch
which limits current over-shoots.
Output Discharge Resistor
The FPF2223/4/5 family contains an 80 on-chip load resistor
for quick output discharge when the switch is turned off. This
features become more attractive when application requires
large output capacitor to be discharge when the switch tunrs off.
However, VOUT pin should not be connected directly to the
battery source due to the discharge mechanism of the load
switch.
On/Off Control
The ON pin is active high, and controls the state of the switch.
Applying a continuous high signal will hold the switch in the on
state. The switch will move into the OFF state when the active
high is removed, or if a fault is encountered. For all versions, an
undervoltage on VIN or a junction temperature in excess of
140°C overrides the ON control to turn off the switch.
In addition, excessive currents will cause the switch to turn off in
the FPF2223 and FPF2224. The FPF2223 has an Auto-Restart
feature which will automatically turn the switch on again after
450ms. For the FPF2224, the ON pin must be toggled to turn-on
the switch again. The FPF2225 does not turn off in response to
an over current condition but instead remains operating in a
constant current mode so long as ON is active and the thermal
shutdown or UVLO have not activated.
Thermal Shutdown
The thermal shutdown protects the die from internally or
externally generated excessive temperatures. During an overtemperature condition the FLAGB is activated and the switch is
turned-off. The switch automatically turns-on again if
temperature of the die drops below the threshold temperature.
Fault Reporting
Upon the detection of an over-current condition, an input UVLO,
or an over-temperature condition, the FLAGB signals the fault
mode by activating LO. In the event of an over-current condition
for the FPF2223 and FPF2224, the FLAGB goes LO at the end
of the blanking time while FLAGB goes LO immediately for the
FPF2225. If the over-current condition lasts longer than
blanking time, FLAGB remains LO through the Auto-Restart
Time for the FPF2223 while for the FPF2224, FLAGB is latched
LO and ON must be toggled to release it. With the FPF2225,
FLAGB is LO during the faults and immediately returns HI at the
end of the fault condition. FLAGB is an open-drain MOSFET
which requires a pull-up resistor between VIN and FLAGB.
During shutdown, the pull-down on FLAGB is disabled to reduce
current draw from the supply. A 100K pull up resistor is
recommended to be used in the application.
Current Limiting
The current limit ensures that the current through the switch
doesn't exceed a maximum value while not limiting at less than
a minimum value. The current at which the parts will limit is
adjustable through the selection of an external resistor
connected to the ISET pin. The FPF2223 and FPF2224 have a
blanking time of 30ms (nominal) during which the switch will act
as a constant current source. At the end of the blanking time,
the switch will be turned-off. The FPF2225 has no current limit
blanking period so it will remain in a constant current state until
the ON pin is deactivated or the thermal shutdown turns-off the
switch.
FPF2223-FPF2225 Rev. C
9
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FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
Description of Operation
Setting Current Limit
720
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 RSET layout. The RSET resistance is selected by
using the following equation:
ILIM (Typ) (mA) =
660
ILIMIT (mA)
600
23764
RSET (K )
540
480
420
Max
360
Typ
300
For a particular ILIM(min) value, RSET can be calculated from
below formula:
34
42
66
74
82
4700
ILIM (Min) (mA)
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 VIN and GND. A 1uF ceramic capacitor, CIN,
placed close to the pins is usually sufficient. Higher values of
CIN can be used to further reduce the voltage drop.
FPF222X family has 5% precision at higher load current. The
ILIM (Max) and tolerance of current limit value can be determined
using Figure 23 (ILIM vs RSET ) and the following formula:
ILIM (Typ) - ILIM (Min)
Output Capacitor
ILIM (Typ)
ILIM (Typ) +
58
Figure 23. ILIM vs RSET
ILIM (Min) (mA) + 25 +
Tolerance (%) = 100 *
50
RSET (KOhms)
23764
RSET (K ) =
ILIM (Max) =
Min
240
A 0.1uF capacitor COUT, should be placed between VOUT and
GND. This capacitor will prevent parasitic board inductances
from forcing VOUT below GND when the switch turns-off. For the
FPF2223 and FPF2224, the total output capacitance needs to
be kept below a maximum value, COUT(max), to prevent the
part from registering an over-current condition and turning-off
the switch. The maximum output capacitance can be
determined from the following formula:
ILIM (Typ) * Tolerance (%)
100
The table and figure below can be used to select RSET:
RSET
[k ]
Min. Current
Limit [mA]
Typ. Current
Limit [mA]
Max. Current
Limit [mA]
Tol
[%]
36.0
627.0
660.0
693.0
5.0
37.5
600.9
633.7
666.5
5.2
39.0
576.2
609.3
642.5
5.4
Power Dissipation
40.2
557.7
591.1
624.5
5.7
42.2
529.3
563.1
597.0
6.0
44.2
503.3
537.6
572.0
6.4
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:
49.0
449.5
485.0
520.4
7.3
51.1
429.1
465.0
501.0
7.7
54.9
396.0
432.9
469.7
8.5
61.9
345.3
383.9
422.5
10.1
69.8
299.8
340.5
381.1
11.9
80.9
250.0
293.7
337.5
14.9
COUT (Max) =
VIN
P = (ILIM)2 * RDS = (0.625)2 * 0.165 = 64mW
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 AutoRestart Time, tRSTRT, and the Over Current Blanking Time,
tBLANK. Therefore, the maximum power dissipated is:
P (Max) =
Table 1: RSET Selection Guide
=
FPF2223-FPF2225 Rev. C
ILIM (Max) * tBLANK (Min)
10
tBLANK
tBLANK + tRSTRT
30
30 + 450
* VIN (Max) * ILIM (Max)
* 5.5 * 0.693 = 0.238W
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FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
Application Information
The following techniques have been identified to improve the
thermal performance of this family of devices.
These
techniques are listed in order of the significance of their impact.
1. Thermal performance of the load switch can be improved by
connecting pin7 of the DAP (Die Attach Pad) to the GND plane
of the PCB.
2. Embedding two exposed through-hole vias into the DAP
(pin7) provides a path for heat to transfer to the back GND
plane of the PCB. A drill size of Round, 14 mils (0.35mm) with
1-ounce copper plating is recommended to result in appropriate
solder reflow. A smaller size hole prevents the solder from
penetrating into the via, resulting in device lift-up. Similarly, a
larger via-hole consumes excessive solder, and may result in
voiding of the DAP.
P (Max) = VIN (MAX) * ILIM (MAX) = 5.5 * 0.693 = 3.8W
This large amount of power will activate the thermal shutdown
and the part will cycle in and out of thermal shutdown so long as
the ON pin is active and the short is present.
PCB Layout Recommendations
In order to benefit from adjustable, high-precision load switch
devices, a high-precision RSET value must be used to set a tight
current limit tolerance. Since ILIMIT (current limit value) is
determined by the voltage drop across the RSET, a poor PCB
layout can introduce parasitic noise on the ISET pin resulting in a
minor variation of ILIMIT. To improve the ILIMIT stability, parasitic
noise coupling mechanisms from ISET to GND must be
minimized. This becomes more critical when ILIMIT is set close
to the nominal load current operation where parasitic effects
could cause the device to go in and out of current limit and
result in an error flag report.
Care must be taken to provide a direct current return path
between the RSET ground pad and the device ground pad
(pin5). Please see current pad #2 in figure below.
Figure 25: Two through hole open vias embedded in DAP
1)Power current path
2)RSET current path
Figure 24: Eliminate parasitic noise of ISET-GND by providing a
separate ground route, unique from the power ground plane
Figure 26: X-Ray result (bottom view with 45o angle)
3. The VIN, VOUT and GND pins will dissipate most of the heat
generated during a high load current condition. Using wide
traces will help minimize parasitic electrical effects along with
minimizing the case to ambient thermal impedance. The layout
suggested in Figure 27 provides each pin with adequate copper
so that heat may be transferred as efficiently as possible out of
the device. The low-power FLAGB and ON pin traces may be
laid-out diagonally from the device to maximize the area
available to the ground pad. Placing the input and output
capacitors as close to the device as possible also contributes to
heat dissipation, particularly during high load currents.
Improving Thermal Performance
An improper layout could result in higher junction temperature
and triggering the thermal shutdown protection feature. This
concern applies when the switch is set at higher current limit
value and an over-current condition occurs. In this case, the
power dissipation of the switch, from the formula below, could
exceed the maximum absolute power dissipation of 1.2W.
PD = (VIN - VOUT) x ILIM (Max)
FPF2223-FPF2225 Rev. C
11
www.fairchildsemi.com
FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
Take note that this is below the maximum package power
dissipation, and the thermal shutdown feature will act as
additional safety to protect the part from damage due to
excessive heating. The junction temperature is only able to
increase to the thermal shutdown threshold. Once this
temperature has been reached, toggling ON will not turn-on the
switch until the junction temperature drops. For the FPF2225, a
short on the output will cause the part to operate in a constant
current state dissipating a worst case power of:
FPF2223-FPF2225 Integrated Load Switch with Adjustable High Precision Current Limit
Figure 30: Zoom in to Top layer
Figure 27: Proper layout of output and ground copper area
FPF22XX Demo Board
FPF22XX Demo board has components and circuitry to
demonstrate FPF2223/4/5 load switches functions and features.
R4 resistor with 0 value is used for measuring the output
current. Load current can be scoped by removing the R4
resistor and soldering a current loop to the R4 footprint. Thermal
performance of the board is improved using a few techniques
recommended in the layout recommendations section of
datasheet.
Figure 28: Top, SST, and AST Layers
Figure 29: Bottom and ASB Layers
FPF2223-FPF2225 Rev. C
12
www.fairchildsemi.com
2.0
0.05 C
A
1.72
1.68
B
2X
6
4
0.15
2.0
1.21
2.25
0.90
0.52(6X)
0.05 C
PIN#1 IDENT
TOP VIEW
1
2X
3
0.65
0.42(6X)
RECOMMENDED
LAND PATTERN
0.10 C
NOTES:
0.08 C
SIDE VIEW
C
A. PACKAGE DOES NOT FULLY CONFORM
TO JEDEC MO-229 REGISTRATION
SEATING
PLANE
B. DIMENSIONS ARE IN MILLIMETERS.
C. DIMENSIONS AND TOLERANCES PER
ASME Y14.5M, 2009.
D. LAND PATTERN RECOMMENDATION IS
EXISTING INDUSTRY LAND PATTERN.
(0.70)
(0.20)4X
PIN #1 IDENT
1
E. DRAWING FILENAME: MKT-MLP06Krev5.
3
(0.40)
(6X)
(0.60)
6
4
(6X)
0.65
1.30
BOTTOM VIEW
0.10
0.05
C A B
C
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