FPF2225 [ONSEMI]
具有可调式精密限流的集成式负载开关;
| 型号： | FPF2225 |
| 厂家： | 
ONSEMI |
| 描述： | 具有可调式精密限流的集成式负载开关 开关 驱动 光电二极管 接口集成电路 |
| 文件： | 总15页 (文件大小：1353K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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February 2009
FPF2223-FPF2225
tm
Integrated Load Switch with Adjustable High Precision Current Limit
Features
General Description
¢ 1.8 to 5.5V Input Voltage Range
The FPF2223-FPF2225 are low R
P-Channel MOSFET
DS(ON)
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.
¢ Typical R
¢ Typical R
= 140mꢀ @ V = 5.5V
IN
DS(ON)
DS(ON)
= 160mꢀ @ V = 3.3V
IN
¢ 250-625mA (min) Adjustable Current Limit
¢ 5% Current Limit Tolerance @ 625mA (min)
¢ 72ꢀ (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 constant-
current 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
Current Limit
Blanking Time
(mS)
Current Limit
Auto-Restart Time
(mS)
ON Pin
Activity
Part
(mA)
FPF2223
FPF2224
FPF2225
250-625
250-625
250-625
30
450
NA
NA
Active HI
Active HI
Active HI
30
NA
©2008 Fairchild Semiconductor Corporation
FPF2223-FPF2225 Rev. C
1
www.fairchildsemi.com
Typical Application Circuit
TO LOAD
FPF2223/4/5
V
V
OUT
IN
FLAGB
OFF ON
ON
I
SET
GND
Functional Block Diagram
V
IN
UVLO
THERMAL
SHUTDOWN
CONTROL
LOGIC
ON
CURRENT
LIMIT
V
OUT
I
SET
Output Discharge
FLAGB
GND
2
www.fairchildsemi.com
FPF2223-FPF2225 Rev. C
Pin Configuration
ON
6
5
4
1
2
3
I
SET
GND
V
V
IN
FLAGB
OUT
MicroFET 2x2 6L
(BOTTOMVIEW)
Pin Description
Pin
Name
Function
1
2
3
I
Current Limit Set Input : A resistor from I
to ground sets the current limit for the switch
SET
SET
V
Supply Input: Input to the power switch and the supply voltage for the IC
Switch Output: Output of the power switch
IN
V
OUT
Fault Output: Active LO, open drain output which indicates an over current, supply
under voltage or over temperature state
4
FLAGB
5
6
GND
ON
Ground
ON/OFF Control Input
Absolute Maximum Ratings
Parameter
Min.
-0.3
Max.
6
Unit
V
V
, V
, ON, FLAGB TO GND
OUT
IN
I
TO GND
-0.3
0.3
1.2
125
86
V
SET
Power Dissipation @ T = 25°C
W
A
Operating and Storage Junction Temperature
Thermal Resistance, Junction to Ambient
Electrostatic Discharge Protection
-65
°C
°C/W
V
HBM
MM
8000
400
V
CDM
2000
V
Recommended Operating Range
Parameter
Min.
1.8
Max.
5.5
Unit
V
V
IN
Ambient Operating Temperature, T
-40
85
°C
A
Electrical Characteristics
V
=1.8to5.5V, T =-40to+85°Cunlessotherwisenoted.TypicalvaluesareatV =3.3V andT =25°C.
IN
A
IN
A
Parameter
Symbol
Conditions
Min. Typ. Max. Units
Basic Operation
Operating Voltage
V
1.8
5.5
75
80
95
2.5
V
IN
I
I
I
=0mA, V =V =1.8V, R
=36K
=36K
=36K
45
50
55
OUT
OUT
OUT
IN
ON
SET
SET
SET
Quiescent Current
I
=0mA, V =V =3.3V, R
ꢁA
ꢁA
Q
IN
ON
=0mA, V =V =5.5V, R
IN
ON
V
Shutdown Current
V
=0V, V =5.5V, V
=short to GND
OUT
IN
ON
IN
3
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FPF2223-FPF2225 Rev. C
Parameter
Symbol
Conditions
Min. Typ. Max. Units
V
Shutdown Current
V
V
V
V
V
V
V
V
V
V
V
V
V
=0V, V
=5.5V, V =short to GND
1
ꢁA
OUT
ON
OUT
OUT
OUT
OUT
OUT
IN
=5.5V, I
=3.3V, I
=1.8V, I
=200mA, T =25°C
140
160
230
185
210
300
265
105
IN
IN
IN
IN
IN
IN
IN
IN
IN
ON
A
=200mA, T =25°C
A
On-Resistance
R
mꢀ
ON
=200mA, T =25°C
A
=3.3V, I
=200mA, T =-40 to +80°C
90
A
Output Discharge Resistance
=3.3V, V =0V, I
=10mA
72
ꢀ
ON
OUT
=1.8V
=5.5V
=1.8V
=5.5V
0.8
1.4
ON Input Logic High Voltage (ON)
V
V
V
IH
IL
0.5
1.0
1
ON Input Logic Low Voltage (OFF)
On Input Leakage
V
ꢁA
V
= V or GND
-1
IN
=5.5V, I
=100ꢁA
0.05
0.12
0.1
0.25
IN
IN
SINK
SINK
FLAGB Output Logic Low Voltage
=1.8V, I
=100ꢁA
FLAGB Output High Leakage
Current
V
=5.5V, Switch on
1
uA
IN
Protections
V
=3.3V, V
= 3.0V, RSET=36K,
OUT
IN
Current Limit
I
627
660
693
mA
°C
LIM
T =25°C
A
Shutdown Threshold
Return from Shutdown
Hysteresis
140
130
10
Thermal Shutdown
Under Voltage Shutdown
Under Voltage Shutdown Hysteresis
Dynamic
UVLO
V
increasing
1.55
1.65
50
1.75
V
IN
mV
Turn On Time
t
t
t
t
t
t
R =500ꢀ, C =0.001uF
70
600
40
ꢁS
nS
ꢁS
nS
mS
mS
ON
L
L
Turn Off Time
R =500ꢀ, C =0.001uF
L L
OFF
V
V
Rise Time
Fall Time
R =500ꢀ, C =0.001uF
L L
OUT
OUT
RISE
FALL
BLANK
RSTRT
R =500ꢀ, C =0.001uF
100
30
L
L
Over Current Blanking Time
Auto-Restart Time
FPF2223, FPF2224
FPF2223
15
60
225
450
900
V
= V
= 3.3V. Over-Current
ON
IN
Current Limit Response Time
5
ꢁS
Condition: R
=V /(I x4)
LOAD
IN LIM
4
www.fairchildsemi.com
FPF2223-FPF2225 Rev. C
Typical Characteristics
80
90
80
70
60
50
40
30
20
VON=V
IN
VON = VIN
70
VIN=3.3V
60
85oC
VIN=5.5V
50
25oC
40
-40oC
VIN=1.8V
30
20
10
-40
-15
10
35
60
85
1
2
3
4
5
6
TJ, JUNCTION TEMPERATURE (oC)
SUPPLY VOLTAGE (V)
Figure 1. Quiescent Current vs. Input Voltage
Figure 2. Quiescent Current vs. Temperature
1.6
1.4
1.2
1
1.4
1.2
1.0
0.8
0.6
0.4
0.2
V
IN=5.5V
VIH
V
IL
VIN=3.3V
0.8
0.6
0.4
0.2
VIN=1.2V
1
2
3
4
5
6
-40
-15
10
35
60
85
TJ, JUNCTION TEMPERATURE (oC)
V , SUPPLY VOLTAGE (V)
IN
Figure 3. V vs. Input Voltage
Figure 4. V
High Voltage vs. Temperature
ON
ON
1.4
0.05
0.04
0.03
0.02
0.01
0.00
-0.01
1.2
1.0
0.8
0.6
0.4
0.2
0.0
V
IN=5.5V
VIN=3.3V
VIN=1.2V
VON = 5.5V
VON = 0V
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TJ, JUNCTION TEMPERATURE (oC)
TJ, JUNCTION TEMPERATURE (oC)
Figure 5. V Low Voltage vs. Temperature
Figure 6. On Pin Current vs. Temperature
ON
5
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FPF2223-FPF2225 Rev. C
Typical Characteristics
700
690
680
670
660
650
640
630
620
800
700
600
500
400
300
200
100
0
R
= 36Kꢀ
SET
VIN = 1.8V
VIN = 3.3V
VIN = 5.5V
0
1
2
3
4
5
6
-40
-15
10
35
60
85
TJ, JUNCTION TEMPERATURE (oC)
V -VOUT (V)
IN
Figure 7. Current Limit vs. Output Voltage
Figure 8. Current Limit vs. Temperature
320
280
240
200
160
120
80
340
300
260
220
180
140
100
60
V
IN=1.8V
85oC
25oC
VIN=3.3V
VIN=5.5V
-40oC
40
-40
-15
10
35
60
85
1.5
2.5
3.5
4.5
5.5
VIN, SUPPLY VOLTAGE(V)
TJ, JUNCTION TEMPERATURE (oC)
Figure 9. R
vs. Input Voltage
Figure 10. R
vs. Temperature
ON
ON
1000
100
10
100
10
1
V
IN = 3.3V
RL = 500 Ohms
COUT = 0.11uF
TRISE
TON
V
IN = 3.3V
RL = 500 Ohms
COUT = 0.11uF
TOFF
TFALL
1
0.1
0.1
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TJ, JUNCTION TEMPERATURE (oC)
TJ, JUNCTION TEMPERATURE (oC)
Figure 11. T
/ T
vs. Temperature
Figure 12. T
/ T
vs. Temperature
OFF
ON
RISE
FALL
6
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FPF2223-FPF2225 Rev. C
Typical Characteristics
1000
TRESTART
V
IN
2V/DIV
100
10
1
I
OUT
10mA/DIV
TBLANK
V
ON
2V/DIV
V =3.3V,
IN
R =500ꢀ,
L
V
OUT
C
R
=10uF,
IN
2V/DIV
=36Kꢀ
SET
-40
-15
10
35
60
85
TJ, JUNCTION TEMPERATURE (oC)
100ꢁs/DIV
Figure 14. Turn On Response
Figure 13. T
vs Temperature
BLANK
1
V
DRV
5V/DIV
V
IN
2V/DIV
I
OUT
I
OUT
500mA/DIV
10mA/DIV
V
=5V, C =10uF,
IN
IN
T
BLANK
V
R =100ꢀ,C
=1uF,
V
ON
L
OUT
FLAGB
2V/DIV
R
=36Kꢀ
2V/DIV
SET
V
=3.3V,
IN
V
OUT
R =500ꢀ,
C
R
V
OUT
2V/DIV
L
2V/DIV
=10uF,
IN
=36Kꢀ
SET
10ms/DIV
Response
500ns/DIV
Figure 15. Turn Off Response
Figure 16. T
BLANK
1
V
ON
V
DRV
V
=5V, C =10uF,
IN
IN
2V/DIV
5V/DIV
R =100ꢀ,C
=1uF,
L
OUT
R
=36Kꢀ
SET
I
OUT
I
OUT
500mA/DIV
10mA/DIV
V
IN
V
V
=3.3V, C =10uF,
IN
T
FLAGB
IN
RESTART
2V/DIV
2V/DIV
R =1.2ꢀ,C
=10uF,
L
OUT
R
=36Kꢀ
SET
V
V
OUT
OUT
2V/DIV
2V/DIV
100ꢁs/DIV
100ms/DIV
Response
Figure 17. T
Figure 18. Current Limit Response
(Output is loaded with 1.2ꢀ resistor and C
RESTART
=10ꢁF)
OUT
Note1: V
signal drives the gate of a NMOS transistor. The NMOS transistor is in series with a 5ꢀ resistor and is connected to the
DRV
output of device. By turning on the transistor, the 5ꢀ resistor is loaded to the output and forces the device to go into overcurrent
condition.
7
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FPF2223-FPF2225 Rev. C
Typical Characteristics
V
=5V, C =10uF,
IN
IN
V
C
=5V, C =10uF,
IN
IN
R =1.2ꢀ, C =100uF,
R
V
V
L
OUT
ON
ON
=100uF,
OUT
=36Kꢀ
2V/DIV
2V/DIV
SET
R =1.2ꢀ,
L
R
=36Kꢀ
SET
I
I
OUT
OUT
500mA/DIV
500mA/DIV
V
V
IN
IN
5V/DIV
5V/DIV
V
V
OUT
OUT
2V/DIV
5V/DIV
500ꢁs/DIV
2ms/DIV
Figure 19. Current Limit Response
(Output is loaded with 1.2ꢀ resistor and C
Figure 20. Current Limit and Output Discharge Response
(Device turns on and off into large capacitive load C =100F)
=100ꢁF)
OUT
OUT
V
=3.3V, C =10uF,
IN
IN
V
V
V
IN= ON
ON
R =100ꢀ,C
R
=1uF,
L
OUT
2V/DIV
2V/DIV
=36Kꢀ
SET
I
I
OUT
OUT
500mA/DIV
5A/DIV
V
=V =3.3V,
ON
IN
C
C
R
=10uF, R =1.2ꢀ,
IN
L
=1uF,
OUT
=36Kꢀ
SET
V
V
OUT
OUT
2V/DIV
2V/DIV
20ꢁs/DIV
50ꢁs/DIV
Figure 21. Current Limit Response
(Switch is powered into a short - Input and
enable pin are tied together)
Figure 22. Short Circuit Response Time
(Output shorted to GND while the switch is in normal operation)
8
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FPF2223-FPF2225 Rev. C
Description of Operation
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 0.16ꢀ
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 80ꢀ 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.
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.
However, V
pin should not be connected directly to the
OUT
battery source due to the discharge mechanism of the load
switch.
Thermal Shutdown
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.
The thermal shutdown protects the die from internally or
externally generated excessive temperatures. During an over-
temperature 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 100Kꢀ 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.
9
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FPF2223-FPF2225 Rev. C
Application Information
Setting Current Limit
720
660
600
540
480
420
360
300
240
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
layout. The R
resistance is selected by
SET
SET
using the following equation:
23764
I
(mA) =
LIM (Typ)
Max
Typ
Min
R
(Kꢀ)
SET
For a particular I (min) value, R
can be calculated from
LIM
SET
34
42
50
58
66
74
82
below formula:
RSET (KOhms)
23764
Figure 23. I
vs R
LIM SET
R
(Kꢀ) =
SET
4700
I
(mA) + 25 +
LIM (Min)
I
(mA)
LIM (Min)
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
FPF222X family has 5% precision at higher load current. The
and tolerance of current limit value can be determined
I
LIM (Max)
using Figure 23 (I
vs R
) and the following formula:
SET
LIM
be placed between V and GND. A 1uF ceramic capacitor, C
,
IN
IN
placed close to the pins is usually sufficient. Higher values of
can be used to further reduce the voltage drop.
C
IN
I
- I
LIM (Typ) LIM (Min)
Output Capacitor
Tolerance (%) = 100 *
I
A 0.1uF capacitor C
, should be placed between V
and
OUT
LIM (Typ)
OUT
GND. This capacitor will prevent parasitic board inductances
from forcing V below GND when the switch turns-off. For the
I
* Tolerance (%)
OUT
LIM (Typ)
I
=
I
LIM (Typ) +
LIM (Max)
FPF2223 and FPF2224, the total output capacitance needs to
be kept below a maximum value, C (max), to prevent the
100
OUT
part from registering an over-current condition and turning-off
the switch. The maximum output capacitance can be
determined from the following formula:
The table and figure below can be used to select R
:
SET
R
Min. Current Typ. Current Max. Current
Limit [mA]
Tol
[%]
SET
[kꢀ]
36.0
37.5
39.0
40.2
42.2
44.2
49.0
51.1
54.9
61.9
69.8
80.9
Limit [mA]
627.0
600.9
576.2
557.7
529.3
503.3
449.5
429.1
396.0
345.3
299.8
250.0
Limit [mA]
660.0
633.7
609.3
591.1
563.1
537.6
485.0
465.0
432.9
383.9
340.5
293.7
I
* t
LIM (Max) BLANK (Min)
693.0
666.5
642.5
624.5
597.0
572.0
520.4
501.0
469.7
422.5
381.1
337.5
5.0
5.2
C
=
OUT (Max)
V
IN
5.4
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:
5.7
6.0
6.4
7.3
2
2
P = (I ) * R = (0.625) * 0.165 = 64mW
LIM
DS
7.7
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-
8.5
10.1
11.9
14.9
Restart Time, t
, and the Over Current Blanking Time,
RSTRT
t
. Therefore, the maximum power dissipated is:
BLANK
t
BLANK
P
=
* V
* I
IN (Max) LIM (Max)
(Max)
t
+ t
RSTRT
BLANK
Table 1: R
Selection Guide
SET
30
=
* 5.5 * 0.693 = 0.238W
30 + 450
10
www.fairchildsemi.com
FPF2223-FPF2225 Rev. C
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:
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
= V
* I
= 5.5 * 0.693 = 3.8W
LIM (MAX)
(Max)
IN (MAX)
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 R
value must be used to set a tight
SET
current limit tolerance. Since I
(current limit value) is
LIMIT
determined by the voltage drop across the R , a poor PCB
SET
layout can introduce parasitic noise on the I
pin resulting in a
stability, parasitic
SET
. To improve the I
LIMIT
minor variation of I
LIMIT
noise coupling mechanisms from
I
to GND must be
SET
minimized. This becomes more critical when I
is set close
LIMIT
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
Figure 25: Two through hole open vias embedded in DAP
between the R
ground pad and the device ground pad
SET
(pin5). Please see current pad #2 in figure below.
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
o
Figure 26: X-Ray result (bottom view with 45 angle)
3. The V , V
and GND pins will dissipate most of the heat
OUT
IN
Improving Thermal Performance
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.
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 = (V - V
) x I
LIM (Max)
IN
OUT
11
www.fairchildsemi.com
FPF2223-FPF2225 Rev. C
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 0ꢀ 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
12
www.fairchildsemi.com
FPF2223-FPF2225 Rev. C
0.05 C
2.0
A
1.72
1.68
2X
B
4
6
0.15
1.21
2.0
0.90
2.25
0.52(6X)
0.05 C
1
3
PIN#1 IDENT
TOP VIEW
2X
0.42(6X)
0.65
RECOMMENDED
LAND PATTERN
ꢂꢁꢈꢃꢂꢁꢂꢃ
0.10 C
ꢂꢁꢀꢂꢂꢁꢂꢃ
NOTES:
0.08 C
SIDE VIEW
C
ꢂꢁꢂꢀꢃꢂꢁꢂꢀꢃ
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.
ꢀꢁꢂꢂꢂꢁꢂꢃ
ꢄꢁꢅꢂꢂꢁꢂꢃ
D. LAND PATTERN RECOMMENDATION IS
EXISTING INDUSTRY LAND PATTERN.
(0.70)
PIN #1 IDENT
(0.20)4X
E. DRAWING FILENAME: MKT-MLP06Krev5.
1
6
3
(0.40)
ꢂꢁꢇꢀꢂꢁꢂꢃ
(6X)
ꢂꢁꢆꢂꢂꢁꢂꢃ
(0.60)
4
(6X)
C A B
ꢂꢁꢇꢂꢂꢁꢂꢃ
0.10
0.65
1.30
0.05
C
BOTTOM VIEW
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