FAIRCHILD FPF2313LMPX_10

FPF2310/12/13/13L
Dual-Output Adjustable Current Limit Switch
Features
Description
„ 1.8 to 5.5V Input Voltage Range
The FPF2310/12/13/13L are dual-channel load switches
of the IntelliMAX™ family. The FPF2310/12/13/13L
consist of dual, independent, current-limited, and slew
rate controlled, P-channel MOSFET power switches.
Slew rated turn-on prevents inrush current from glitching
supply rails. The input voltage range operates from 1.8V
to 5.5V to fulfill USB device supply requirements. Switch
control is accomplished by a logic input (ON) capable of
interfacing directly with low-voltage control signals.
„ Typical RON = 75mΩ at IN = 5.5V
„ 400~600mA Adjustable Current Limit
„ 10% Current Limit Accuracy from Typical
„ Slew Rate Controlled
„ ESD Protected, Above 4000V HBM
„ Independent Thermal Shutdown
„ UVLO
„ Output Discharge
For the FPF2312, if the constant-current condition
persists after 10ms, the part shuts down the switch. The
FPF2310 has an auto-restart feature that turns the
switch on again after 150ms if the ON pin is still active.
FPF2313/13L remains in constant-current mode until the
switch current falls below the current limit. For FPF2310
through FPF2313/13L, the minimum current limit is
400mA-600mA with 10% accuracy (+25°C) for each switch
to comply with USB applications in portable devices.
„ RoHS Compliant
Applications
„ Smart Phones
FPF2310M/12/13/13L series is available in a spacesaving, 8-Lead, 3x3mm MLP.
„ Enterprise Equipment
„ Peripheral USB Ports and Accessories
Related Resources
FPF2310/12/13/13L Evaluation Board User Guide;
Power Switch for USB Applications
Figure 1. 8-Lead MLP (3x3mm)
Ordering Information
Part Number
Minimum Current Limit
Auto
Current
Blanking
Restart
Limit
Time
FPF2310MPX
400-600mA
10ms
150ms
FPF2312MPX
400-600mA
10ms
N/A
Active HIGH Latch Off 8-Lead Molded Leadless Package
FPF2313MPX
400-600mA
0ms
N/A
Active HIGH
Constant
8-Lead Molded Leadless Package
Current
FPF2313LMPX 400-600mA
0ms
N/A
Active LOW
Constant
8-Lead Molded Leadless Package
Current
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
ON Pin
Activity
Mode
Active HIGH
Restart
Package
8-Lead Molded Leadless Package
www.fairchildsemi.com
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
May 2010
ISETA
IN
ISETB
FPF2310/12/13/13L*
IN = 1.8V-5.5V
CIN
OFF ON
ONA
OFF ON
ONB
GND
OUTA
TO LOAD A
OUTB
TO LOAD B
COUTB
COUTA
*FPF2313L is active LOW
Figure 2. Typical Application
Functional Block Diagram
IN
UVLO
ONA
CONTROL
LOGIC A
CURRENT
LIMIT A
OUTA
THERMAL
PROTECTION A
OUTPUT
DISCHARGE
ISETA
ONB
CONTROL
LOGIC B
CURRENT
LIMIT B
OUTB
THERMAL
PROTECTION B
OUTPUT
DISCHARGE
ISETB
GND
Figure 3. Block Diagram
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
www.fairchildsemi.com
2
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Application Circuit
ISETA
8
OUTA
7
1
GND
2
IN
ONA
9
OUTB
6
3
ISETB
5
4 ONB
MLP 3X3 8L Bottom View
Figure 4. 8-Lead MLP 3x3mm (Bottom View)
Pin Description
Pin
Name
1
GND
Function
Ground
2
IN
3
ONA
Supply Input: Input to the power switch and the supply voltage for the IC.
ON / OFF control input of power switch A.
4
ONB
ON / OFF control input of power switch B.
5
ISETB
Current limit set input for power switch B: A resistor from ISET to ground sets the current limit for
the switch.
6
OUTB
Switch Output: output of the power switch B.
7
OUTA
Switch Output: output of the power switch A.
8
ISETA
Current limit set input for power switch A: A resistor from ISET to ground sets the current limit for
the switch.
9
Thermal Pad
IC substrate, which can be connected to GND for better thermal performance. Do not connect to
other pins.
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
www.fairchildsemi.com
3
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Pin Configuration
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The
absolute maximum ratings are stress ratings only.
Symbol
Parameter
IN, OUTA, OUTB, ON to GND
PD
TSTG
Min.
Max.
Unit
-0.3
6.0
V
0.6
Power Dissipation
2.2(2.)
Storage Temperature
ΘJA
Thermal Resistance, Junction-to-Ambient
ESD
Electrostatic Discharge Protection
(1.)
-65
+150
216(1.)
57(2.)
W
°C
°C/W
Human Body Model, JESD22-A114
4000
V
Charged Device Model, JESD22-C101
2000
V
Notes:
1. Soldered thermal pad on a two-layer PCB without vias based on JEDEC STD 51-3.
2.
Soldered thermal pad on a four-layer PCB without vias connected with GND plane based on JEDEC STD51-5, 7.
Recommended Operating Range
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended
operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not
recommend exceeding them or designing to absolute maximum ratings.
Symbol
Parameter
Min.
Max.
Unit
IN
Supply Input
1.8
5.5
V
TA
Ambient Operating Temperature
-40
+85
°C
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
www.fairchildsemi.com
4
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Absolute Maximum Ratings
IN = 1.8 to 5.5V, TA = -40 to +85°C unless otherwise noted. Typical values are at IN = 3.3V and TA = 25°C.
Symbol Parameter
Conditions
Min. Typ. Max. Units
Basic Operation
VIN
Operating Voltage
1.8
IQ
Quiescent Current
IN = 5.5V, IOUT = 0mA,
VON = 5.5V (FPF2310/2/3), VON = 0V (FPF2313L)
ISD
IN Shutdown Current
IN = 5.5V, OUTA = OUTB = Short to GND,
VON = 0V (FPF2310/2/3), VON = 5.5V (FPF2313L)
RON
On Resistance
RPD
Output Pull-Down Resistance
VIH
ON Input Logic High Voltage (ON)
VIL
ON Input Logic Low Voltage
ION
ON Input Leakage
VON = IN or GND
ILIM
Current Limit
IN = 3.3V, OUTA = OUTB = 3V,
RSET = 690Ω, TA = 25°C
Shutdown Threshold
140
TSD
Thermal Shutdown
Return from Shutdown
130
VUVLO
Under-Voltage Shutdown
IN Increasing
VUVLO_HYS
Under-Voltage Shutdown
Hysteresis
52.5
IN = 5.5V, IOUT = 200mA, TA = 25°C
75
IN = 5.5V, IOUT = 200mA, TA = -40°C to +85°C
90
IN = 3.3V, TA = 25°C
VON = 0V (FPF2310/2/3), VON = 3.3V(FPF2313L)
70
IN = 1.8V
0.8
IN = 5.5V
1.4
5.5
V
94.5
μA
1
μA
140
mΩ
Ω
V
IN = 1.8V
0.5
IN = 5.5V
0.9
-1
V
1
μA
550
mA
Protections
450
Hysteresis
500
°C
10
1.55
1.65
1.75
V
50
mV
111
μs
Dynamic
tON
Turn-On Time
RL = 500Ω, CL = 0.1μF
tOFF
Turn-Off Time
RL = 500Ω
5
μs
tR
OUTA, OUTB Rise Time
RL = 500Ω, CL = 0.1μF
13
μs
tF
OUTA, OUTB Fall Time
RL = 500Ω
tBLANK
Over-Current Blanking Time
FPF2310, FPF2312
5
10
20
ms
tRSTRT
Auto-Restart Time
FPF2310
75
150
300
ms
Current Limit Response Time
IN = 3.3V, Moderate Over-Current Condition
tCLR
OUT
2
90%
μs
90%
10%
10%
tR
ON
20
μs
tF
50%
50%
90%
OUT
10%
tDON
tDOFF
tON = tR + tDON
tOFF = tF + tDOFF
Figure 5. Timing Diagram
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
www.fairchildsemi.com
5
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Electrical Characteristics
70.00
60.00
ONA = ONB = IN
RSET = 698 Ohms
60.00
ONA = ONB = IN
RSET = 698 Ohms
85°C
50.00
IN = 3.3V
IQ CURRENT (uA)
SUPPLY CURRENT (uA)
55.00
45.00
25°C
40.00
-40°C
35.00
30.00
50.00
IN = 5.5V
40.00
IN = 1.8V
30.00
20.00
10.00
25.00
0.00
-40
20.00
1.8
2.2
2.5
2.9
3.3
3.7
4.0
4.4
4.8
5.1
5.5
-15
Figure 6. Quiescent Current vs. Supply Voltage
IN SHUTDOWN CURRENT (uA)
IN SHUTDOWN CURRENT (uA)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
-15
10
35
60
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-40
85
-15
35
60
85
Figure 9. RON vs. Supply Voltage
110
85
IN = 5.5V
ONA = ONB = 5.5V
RSET = 698 Ohms
IOUT = 200mA
TA = 25°C
PULL-DOWN RESISTANCE (Ohm)
ON RESISTANCE (mOhm)
10
TJ, JUNCTION TEMPERATURE (°C)
Figure 8. IN Shutdown Current vs. Temperature
80
RON B
70
RON A
60
50
-40
85
IN = 5.5V
ON = OUT = 0V
RSET = 698 Ohms
1.8
TJ, JUNCTION TEMPERATURE (°C)
90
60
2.0
IN = 5.5V
ON = OUT = 0V
RSET = 698 Ohms
1.8
100
35
Figure 7. Quiescent Current vs. Temperature
2.0
0.0
-40
10
TJ, JUNCTION TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
-15
10
35
60
TJ, JUNCTION TEMPERATURE (°C)
RPD A
75
RPD B
70
65
2.2
2.5
2.9
3.3
3.7
4.0
4.4
4.8
5.1
5.5
SUPPLY VOLTAGE (V)
Figure 10. RON vs. Temperature
Figure 11. RPD vs. Supply Voltage
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
80
60
1.8
85
ONA = ONB = 0V
RSET = 698 Ohms
IOUT = 1mA
TA = 25°C
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6
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Typical Characteristics
1.5
ON THRESHOLD VOLTAGE (V)
PULL-DOWN RESISTANCE (Ohm)
80
75
RPDA
70
RPDB
65
60
IN = 5.5V
ONA = ONB = 0V
RSET = 698 Ohms
IOUT = 1mA
55
50
-40
RSET = 698 Ohms
TA = 25°C
1.3
1.0
VIH
0.8
VIL
0.5
0.3
0.0
-15
10
35
60
85
1.8
2.2
2.5
2.9
TJ, JUNCTION TEMPERATURE (°C)
Figure 12. RPD vs. Temperature
3.7
4.0
4.4
5.1
5.5
1.4
1.2
1.0
ON THRESHOLD VOLTAGE (V)
IN = 5.5V
IN = 3.3V
0.8
IN = 1.8V
0.6
0.4
0.2
1.2
IN = 5.5V
1.0
IN = 3.3V
0.8
IN = 1.8V
0.6
0.4
0.2
RSET = 698 Ohms
0.0
-40
-15
10
35
60
RSET = 698 Ohms
0.0
-40
85
-15
TJ, JUNCTION TEMPERATURE (°C)
10
35
60
85
TJ, JUNCTION TEMPERATURE (°C)
Figure 14. ON High Voltage vs. Temperature
Figure 15. ON Low Voltage vs. Temperature
500
500
RSET = 698 Ohms
TA = 25°C
498
495
CURRENT LIMIT (mA)
CURRENT LIMIT (mA)
4.8
Figure 13. ON Threshold Voltage vs. Supply Voltage
1.4
ON THRESHOLD VOLTAGE (V)
3.3
SUPPLY VOLTAGE (V)
ILIM(Typ)B
490
ILIM(Typ)A
485
496
494
IN = 3.3V
OUTA = OUTB = 3V
ONA = ONB = 3.3V
RSET = 698 Ohms
492
ILIM(Typ)B
490
488
ILIM(Typ)A
486
484
482
480
1.8
2.2
2.5
2.9
3.3
3.7
4.0
4.4
4.8
5.1
480
-40
5.5
Figure 16. Current Limit vs. Supply Voltage
10
35
60
85
Figure 17. Current Limit vs. Temperature
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
-15
TJ, JUNCTION TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
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7
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Typical Characteristics
20
IN = 3.3V
RL = 500 Ohms
CL = 0.1 uF
RSET = 698 Ohms
tDON
16
100
IN = 3.3V
RL = 500 Ohms
RSET = 698 Ohms
10
tDOFF
tR
14
12
10
8
-15
10
35
60
4
tF
0
-40
85
-15
TJ, JUNCTION TEMPERATURE (°C)
180
10.5
OUTB
10.0
9.5
170
OUTA
160
150
OUTB
140
130
120
9.0
110
8.5
-40
-15
10
35
60
100
-40
85
-15
TJ, JUNCTION TEMPERATURE (°C)
IN
5V/DIV
ON
2V/DIV
IN = 5V
ON = 3.3V
COUT = 0.1μF
RL = 500Ω
RSET = 680Ω
IOUT
50mA/DIV
60
85
IN = 5V
ON = 3.3V
CIN = 10μF
COUT = 0.1μF
RL = 500Ω
RSET = 680Ω
OUT
5V/DIV
200μs/DIV
200μs/DIV
Figure 22. tON Response
Figure 23. tOFF Response
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
35
Figure 21. tRSTRT vs. Temperature
IN
5V/DIV
ON
2V/DIV
10
TJ, JUNCTION TEMPERATURE (°C)
Figure 20. tBLANK vs. Temperature
OUT
5V/DIV
85
FPF2310
IN = 3.3V
ONA = ONB = 3.3V
RSET = 698 Ohms
190
OUTA
11.0
60
200
RESTART TIME (ms)
BLANKING TIME (ms)
11.5
35
Figure 19. tRISE / tFALL vs. Temperature
FPF2310/12
IN = 3.3V
ONA = ONB = 3.3V
RSET = 698 Ohms
12.0
10
TJ, JUNCTION TEMPERATURE (°C)
Figure 18. tDON / tDOFF vs. Temperature
12.5
IN = 3.3V
RL = 500 Ohms
RSET = 698 Ohms
6
2
1
-40
IN = 3.3V
RL = 500 Ohms
CL = 0.1 uF
RSET = 698 Ohms
18
RISE/FALL TIME (us)
TURN ON/OFF DELAY TIME (us)
1000
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8
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Typical Characteristics
IN
5V/DIV
IN
5V/DIV
IN = 5V
ON = 3.3
CIN = 10μF
COUT = 10μF
RL = 3.3Ω
RSET = 680Ω
ON
2V/DIV
IOUT
500mA/DIV
tBLANK
OUT
5V/DIV
IN = 5V
ON = 3.3
CIN = 10μF
COUT = 10μF
RL = 3.3Ω
RSET = 680Ω
ON
2V/DIV
IOUT
500mA/DIV
OUT
5V/DIV
4ms/DIV
40ms/DIV
Figure 24. tBLANK Response (FPF2310/12)
Figure 25. tRSTRT Response (FPF2310)
IN
5V/DIV
IN
5V/DIV
ON
2V/DIV
IN = 5V
ON = 3.3
ON
2V/DIV
IN = 5V
ON = 3.3V
CIN = 10μF
COUT = 47μF
IOUT
500mA/DIV
OUT
5V/DIV
COUT = 47μF
RL = 10Ω
RSET = 680Ω
OUT
5V/DIV
COUT = 220μF
COUT = 470μF
1ms/DIV
200μs/DIV
Figure 27. Output Voltage Rise Time with
Various Load Capacitor
Figure 26. Current Limit Response with 47μF
IN
5V/DIV
IN
5V/DIV
ON
2V/DIV
ON
2V/DIV
IOUT
500mA/DIV
RL = 10Ω
RSET = 680Ω
COUT = 100μF
IOUT
500mA/DIV
COUT = 470μF
COUT = 220μF
IN = 5V
ON = 3.3
RL = 10Ω
RSET = 680Ω
COUT = 100μF
COUT = 47μF
IOUT
500mA/DIV
COUT = 470μF
COUT = 220μF
COUT = 100μF
IN = 5V
ON = 3.3
RL = 10Ω
RSET = 680Ω
COUT = 47μF
8μs/DIV
40μs/DIV
Figure 28. Output Current Inrush at Startup with
Various Load Capacitors
Figure 29. Output Current Inrush at Startup with
Various Load Capacitors
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
www.fairchildsemi.com
9
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Typical Characteristics
IN
5V/DIV
ON
2V/DIV
IN = 5V
ON = 3.3
COUTA = 100μF
COUTB = 100μF
OUTA
500mV/DIV
RLA = RLB = 1Ω
RSET = 680Ω
IN
5V/DIV
IN = 5V
CIN = 150μF
COUT = 47μF
CL = 150μF
RL = 10Ω
RSET = 680Ω
ON
2V/DIV
IOUT
2A/DIV
OUTB
500mV/DIV
OUT
5V/DIV
400μs/DIV
400μs/DIV
Figure 30. Current Limit Response Time Both
Channels are in OC
Figure 31. Inrush Response During Capacitive Load
Hot Plug-In Event
IN
5V/DIV
IN = 5V
CIN = 150μF
COUT = 100μF
CL = 47μF
RL = 10Ω
RSET = 680Ω
ON
2V/DIV
IOUT
2A/DIV
OUT
5V/DIV
400μs/DIV
Figure 32. Inrush Response During Capacitive and
Resistive Load Hot Plug-In Event
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
www.fairchildsemi.com
10
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Typical Characteristics
The FPF2310/2/3/3L are dual-output current-limit switches
designed to meet notebook computer, peripheral USB port, and
point-of-load (POL) application power requirements. Dual-output
current can be used where two USB ports are powered by hosts
or self-powered hubs. The FPF231X family offers control and
protection while providing optimum operation current for safe
design practices. The core of each switch is a 75mΩ (IN = 5.5V)
P-channel MOSFET and a controller capable of functioning over
an input operating range of 1.8 to 5.5V. The FPF231X offers
current limiting, UVLO (under-voltage lockout), and thermal
shutdown protection in each switch. In the event of an overcurrent condition, the load switch limits the load to current limit
value. The current limit value for each switch can be adjusted
through the ISET pins. 400mA-600mA is adjustable for the
FPF2310 through FPF2313. The minimum current limit is
400mA-600mA with 10% accuracy at +25°C with minimum
variation over temperature.
ON
VIN
VOUT
ILOAD
tRSTRT
ILIMIT
Over
current
condtion
On/Off Control
Figure 33. FPF2310 Performance While Entering into
an Over-Current Condition.
The ON pin is active HIGH for FPF2310/2/3 and controls the
state of the switch. Pulling the ON pin continuous to HIGH holds
the switch in ON state. The switch moves into the OFF state
when the ON pin is pulled LOW or if a fault is encountered.
FPF2313L is active LOW and performs in reverse order. For all
versions, an under-voltage on input voltage or a junction
temperature in excess of 140°C overrides the ON control to turn
off the switch. In addition, excessive currents cause the switch to
turn off in the FPF2310 and FPF2312 after 10ms blanking time.
The FPF2310 has an auto-restart feature that automatically turns
the switch ON again after 150ms. For the FPF2312, the ON pin
must be toggled to turn on the switch again. The FPF2313 and
FPF2313L do not turn off in response to an over-current
condition, but remain operating in a constant-current mode as
long as ON is enabled and the thermal shutdown or UVLO is not
activated. The ON pin does not have a pull-down or pull-up
resistor and should not be left floating.
Note:
3.
An over-current condition signal loads the output with a
heavy load current larger than ILIM value.
ON
VIN
VOUT
Current Limiting
ILOAD
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. FPF231X family has dual-output load switches in
one package. The current limit of each switch is adjustable
through the an external resistor connected to the ISET pin. The
current limit range is from 400mA to 600mA with 10% current limit
tolerance.
ILIMIT
Therm
al Sh
wn
utdo
Dev
ice
Co
ols
O
ff
Over
current
condtion
Figure 34. FPF2313 Performance While Entering into
an Over-Current Condition
The FPF2310 and FPF2312 have a blanking time of 10ms
(tBLANK(Typ) = 10ms) during which the switch acts as a constant
current source.
Note:
4
If the over-current condition persists beyond the blanking time,
the FPF2310 latches off and shuts the switch off. If the ON pin is
kept active, an auto-restart feature releases the switch and turns
the switch on again after a 150ms auto-restart time (tRSTRT). If
the over-current condition persists beyond the blanking time, the
FPF2312 has a latch-off feature that shuts the switch off. The
switch is kept off until the ON pin is toggled. The FPF2313/3L
have no current-limit blanking period, so remain in a constantcurrent state until the ON pin of the affected switch is deactivated
or the thermal shutdown turns off the switch.
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
RL*ILMIT
tBLANK
An over-current condition signal loads the output with a
heavy load current larger than ILIM value.
www.fairchildsemi.com
11
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Description of Operation
Minimum
Current
Limit
[mA]
Typical
Current
Limit
[mA]
511
607
674
742
10
536
578
643
707
10
562
552
613
674
10
RSET
[Ω]
The FPF2310/2/3 and FPF2313L family contains an 70Ω onchip output pull-down resistor for quick output discharge when
the switch is turned off. This features become more attractive
when an application requires a large output capacitor to be
discharged when switch turns off. However, the OUT pin should
not be connected directly to the battery source due to the
discharge mechanism of the load switch.
Maximum
Tolerance
Current
(%)
Limit [mA]
590
526
584
642
10
620
500
556
611
10
649
478
531
584
10
681
455
506
556
10
732
424
471
518
10
775
400
445
489
10
Thermal Shutdown
The thermal shutdown protects the device from internally or
externally generated excessive temperatures. Each switch has
an individual thermal shutdown protection function and operates
independently as adjacent switch temperature increases above
140°C. If one switch is in normal operation and shutdown
protection of second switch is activated, the first channel
continues to operate if the affected channel's heat stays
confined. The over-temperature in one channel can shut down
both switches due to rapidly generated excessive load currents
resulting in very high power dissipation. Generally, a thermally
improved board layout can provide heat sinking and allow heat
to stay confined and not affect operation of the second switch.
ILIMIT (mA)
During an over-temperature condition, the affected switch is
turned off. If the temperature of the die drops below the
threshold temperature, the switch automatically turns on again.
To avoid unwanted thermal oscillations, a 10°C (typical) thermal
hysteresis is implemented between thermal shutdown entry and
exit temperatures.
If output of both switches are connected together and an
excessive load current activates thermal protection of both, the
controller can shutdown the switches after both outputs go LOW
and turn on both channels again. This provides a simultaneous
switch turn on. Thermal protection is for device protection and
should not be used as regular application operation.
RSET (Ω)
Figure 35. ILIM vs. RSET
Under-Voltage Lockout (UVLO)
The under-voltage lockout feature turns off the switch if the
input voltage drops below the under-voltage lockout threshold.
With the ON pin is active (ON pin is pulled LOW), the input
voltage rising above the under-voltage lockout threshold causes
a controlled turn-on of the switch and limits current overshoot.
The device detects the UVLO condition when input voltage goes
below UVLO voltage, but remains above 1.3V (typical).
ON
device wake-up
IN
UVLO THRESHOLD
RISE
TIME
OUT
90% VOUT
10% VOUT
ILOAD
ILIMIT
Figure 36. Under-Voltage Lockout (UVLO)
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
www.fairchildsemi.com
12
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Output Discharge Resistor
Table 1: RSET Selection Guide
ISETA
ISETB
IN
Host (5V)
1µF
OFF
ON
ONA
OFF
ON
ONA
FPF2310/2/3
OUTA
GND
Downstream
USB Port
33µF
Downstream
USB Port
OUTB
33µF
Figure 37. Typical Application
Input Capacitor
Power Dissipation
To limit the voltage drop on the input supply caused by transient
inrush currents when the switch is turned on into discharged
load capacitors or a short-circuit; an input capacitor, CIN, is
recommended between IN and GND. The FPF2310/2/3/3L
features a fast current limit response time of 20μs. An inrush
current (also known as surge current) could occur during the
current limit response time while the switch is responding to an
over-current condition caused by large output capacitors. A
10μF ceramic capacitor, CIN, is required to provide charges for
the inrush current and prevent input voltage drop at the turn on.
Higher values of CIN to further reduce the voltage drop.
During normal operation as a switch, the power dissipation of
device is small and has little effect on the operating temperature
of the part. The maximum power dissipation for both switches,
while the switch is in normal operation, occurs just before both
channels enter into current limit. This may be calculated using:
PD_MAX(NormalOperation) = 2 x (ILIM(MIN))2 x RON(MAX)
(4)
For example, for a 5V application maximum normal operation
power loss while both switches delivering output current up to
500mA (ILIM(MIN) = 500mA) can be calculated as:
PD_MAX(NormalOperation)(IN = 5V) = 2 x (0.5)2 x 0.14
Output Capacitor
A 0.1μF to 1μF capacitor, COUT, should be placed between the
OUT and GND pins. This capacitor prevents parasitic board
inductances from forcing output voltage below GND when the
switch turns off. This capacitor should have a low dissipation
factor. An X7R MLCC (Multilayer Ceramic Chip) capacitors is
recommended.
For the FPF2310 and FPF2312, the total output capacitance
needs to be kept below a maximum value, COUT(MAX), to
prevent the part from registering an over-current condition
beyond the blanking time and shutdown. The maximum output
capacitance for a giving input voltage can be determined from
the following:
ILIM(MIN) x tBLANK(MIN)
(2)
COUT(MAX) =
VIN
For example, in a 5V application and ILIM(MIN) = 500mA using
RSET = 620Ω, COUT(MAX) can be determine as:
0.5A x 5ms
(3)
COUT(MAX)(IN = 5V) =
5
=
=
70mW
The maximum junction temperature should be limited to 125°C
under normal operation. Junction temperature can be
calculated using:
(6)
TJ = PD x RθJA + TA
where:
TJ is junction temperature;
PD is power dissipation across the switch
RθJA is thermal resistance, junction-to-ambient; and TA
is ambient temperature
For example, TJ(MAX)(Normal operation) for an MLP 3x3mm
package with TA=25°C while both switches are delivering up to
1.1A, is calculated as:
TJ(MAX)(NormalOperation)
= PD_MAX(Normal Operation)(IN = 5V) x 216 + 25
= 40.12°C
(7)
500μF
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
(5)
www.fairchildsemi.com
13
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Application Information
1µF
OFF
ON
ONA
OFF
ON
ONA
FPF2310/2/3
OUTA
GND
Downstream
USB Port
OUTB
33µF
Figure 38. Self-Power USB for High Current Demand
PCB Layout Recommendations
If the part goes into current limit, the maximum power
dissipation occurs when the output of switch is shorted to
ground. For the FPF2310, the power dissipation scales with the
auto-restart time, tRSTRT, and the over-current blanking time,
tBLANK. In this case, the maximum power dissipated for the
FPF2310 is:
tBLANK
PD_MAX(CurrentLimit) = 2 x
x IN(MAX) x ILIM(MAX)
tBLANK + tRSTRT
(8)
For the best performance, all traces should be as short as
possible. To be most effective, the input and output capacitors
should be placed close to the device to minimize the effects that
parasitic trace inductances may have on normal and shortcircuit operation. Using wide traces for IN, OUTs, and GND pins
helps minimize parasitic electrical effects along with minimizing
the case-to-ambient thermal impedance.
Improving Thermal Performance of the
FPF231X Family of Devices
Which results in:
PD_MAX(CurrentLimit) = 2 x
10
x 5.5 x 0.74 = 508mW (9)
10 + 150
Improper layout could result in higher junction temperature and
triggering the thermal shutdown protection feature. This concern
applies particularly to the FPF2313 and FPF2313L, where both
channels operate in constant-current mode in the overload
conditions and; during fault condition, the outputs are shorted,
resulting to large voltage drop across switches. In this case,
power dissipation of the switch (PD = (VIN - VOUT) x ILIM(MAX))
could exceed the maximum absolute power dissipation of part.
Note that this is below the maximum package power dissipation
and the thermal shutdown feature protection provides 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 has no effect until the junction
temperature drops below the thermal shutdown exit
temperature. For the FPF2313 and FPF2313L, a short on the
both outputs causes both switches to operate in a constantcurrent state and dissipating a worst-case power of:
PMAX = IN(MAX) x ILIM(MAX) = 2 x 5.5 x 0.74 = 8.14W
The following techniques improve the thermal performance of
this family of devices. These techniques are listed in order of
the significance of impact.
1. Thermal performance of the load switch can be improved by
connecting the DAP (Die Attach Pad) of MLP 3x3mm
package to the GND plane of the PCB.
(10)
2. Embedding two exposed through-hole vias into the DAP (pin
9) provides a path for heat to transfer to the back GND plane
of the PCB. A drill size of round, 15 mils (0.4mm) with 1ounce copper plating is recommended to create 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 the DAP.
As both FPF2313/3L outputs are connected to GND.
This power dissipation is significant and activates both thermal
shutdown blocks. The part cycles in and out of thermal
shutdown as long as the ON pin is activated (pulled LOW) and
the output short is present.
If high current of over 1A is required to supply enough power to
a downstream function, dual outputs can be tied together as
shown in Figure 38.
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
www.fairchildsemi.com
14
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
ISETA
ISETB
IN
Host (5V)
25mil
Figure 39. Two Through-Hole Open Vias
Embedded in DAP
3. The IN, OUTs, and GND pins dissipate most of the heat
generated during a high-load current condition. The layout
suggested in Figure 39 illustrates a proper layout for devices
in MLP 3x3mm packages. IN, OUTs, and GND pins are
connected to adequate copper so that heat may be
transferred as efficiently as possible out of the device. The
low-power FLAGB and ON pins’ 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.
Figure 41. Top, SST, and AST Layers
(MLP 3x3mm Package)
Figure 42. Zoom In to Top Layer
Figure 40. Proper Layout of Output and
Ground Copper Area
FPF231X Evaluation Board
FPF231X evaluation board has components and circuitry to
demonstrate FPF2310/2/3/3L load switches functions and
features accommodating both MLP 3x3mm packages. The state
of the each channel can be configured using J1 and J2 jumpers.
In addition, both channels can be controlled by ONA and ONB
test pins. Thermal performance of the board is improved using
techniques recommended in the layout recommendations
section. R3 and R4 resistors are used on the board to sink a
light load current when switches are activated.
Figure 43. Bottom and ASB Layers
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
www.fairchildsemi.com
15
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
15mil
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
Dimensional Outline and Pad Layout
Figure 44. 8-Lead Molded Leadless Package (MLP)
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner
without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or
obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions,
specifically the warranty therein, which covers Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/.
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
www.fairchildsemi.com
16
FPF2310/12/13/13L — Dual-Output Adjustable Current Limit Switch
© 2009 Fairchild Semiconductor Corporation
FPF2310/12/13/13L • Rev. 1.1.3
www.fairchildsemi.com
17