FPF2025 [FAIRCHILD]
Full Functional Load Switch With 100mA Current Limit; 全功能负载开关提供100mA电流限制
| 型号： | FPF2025 |
| 厂家： | 
FAIRCHILD SEMICONDUCTOR |
| 描述： | Full Functional Load Switch With 100mA Current Limit |
| 文件： | 总17页 (文件大小：745K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
September 2008
FPF2024/5/6/7
Full Functional Load Switch With 100mA Current Limit
Features
General Description
1.6V to 5.5V Input Voltage Range
Ultra Low Average Quiescent Current 1µA typ @1.8V
Typical RDS(ON) = 225mΩ @ VIN = 3.3V
Typical RDS(ON) = 280mΩ @ VIN = 1.8V
100mA Fixed Current Limit Minimum
Under Voltage Lockout
The FPF2024/5/6/7 are low RDS(ON) P-Channel MOSFET load
switches with 150mA typical current limit value targeting small
package load switch applications. The extended input voltage
range spans from 1.6V to 5.5V to fulfill today's Ultra Portable
Device's supply requirements. Switch control is by a logic input
(ON) capable of interfacing directly with a low voltage control
signal.
CMOS and Open Drain Fault Flag Options
Fault Blanking
The FPF2024/5/6/7 respond to an output overload condition by
going into constant current mode where the output current is
regulated by the load switch. If the overcurrent condition
persists beyond the 10ms Blanking Time, FPF2024 and
FPF2025 pull the fault signal pin (FLAGB) low and shut-off the
switch. An Auto-Restart feature turns FPF2024 and FPF2025
on again after 70ms if the ON pin is still active. The FPF2026
has a Latch-Off feature which shuts off the switch off after the
expiration of the 10ms Blanking Time and keeps it off until the
ON pin is toggled. The FPF2027 responds to an overload
condition by immediately pulling the fault signal pin low and the
switch remains in constant current mode until the output
overload condition is removed. FPF2027 has a Startup Blanking
feature which prevents startup transient overcurrent conditions
from triggering the fault signal pin for 10ms after initial turn on
via the ON pin.
Auto Restart
Thermal Shutdown
ESD Protection above 5500V HBM and 1500V CDM
Applications
PDAs
Cell Phones
GPS Devices
Digital Cameras
Peripheral Ports
MP3 Players
These parts are available in a space-saving 6 ball advanced.
Pb-Free 1.0x1.5 mm2 CSP package.
Pin 1
V
IN
NC
V
OUT
ON
GND
FLAGB
BOTTOM
TOP
Ordering Information
Blanking
Current
Limit Time
[ms]
Min Current
Auto-Restart
ON Pin
Activity
Part
Limit
[mA]
Time
[ms]
FLAGB
Top Mark
FPF2024
FPF2025
FPF2026
FPF2027
100
100
100
100
10
10
10
0
70
70
Active HI
Active LO
Active HI
Active HI
Open Drain
CMOS
S2
S3
S4
S5
NA
NA
Open Drain
Open Drain
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
1
www.fairchildsemi.com
Typical Application Circuit
VIN
V
OUT
TO LOAD
FPF2024, FPF2026, FPF2027
ON
FLAG
B
OFF
ON
VIN
V
OUT
TO LOAD
FPF2025
ON
FLAG
B
OFF
ON
Functional Block Diagram
VIN
FPF2024, FPF2026, FPF2027
UVLO
CONTROL
LOGIC
ON
THERMAL
PROTECTION
CURRENT
LIMIT
FLAGB
VOUT
GND
VIN
FPF2025
UVLO
ON
CONTROL
LOGIC
THERMAL
PROTECTION
CURRENT
LIMIT
FLGAB
VOUT
GND
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
2
www.fairchildsemi.com
Pin Configuration
VOUT
VIN
NC
ON
A2
B2
C2
A1
B1
C1
GND
OUTB
FLAGB
1.0X1.5CSP Bottom View
Pin Description
Pin
A1
Name
Function
VOUT
VIN
Switch Output: Output of the power switch
A2
Supply Input: Input to the power switch and the supply voltage for the IC
B1
GND
NC
Ground
B2
No Connection
Fault Output: Active LO, open drain output for FPF2024/6/7 and CMOS output for FPF2025.
FLAGB indicates an over current, supply under voltage or over temperature state
C1
C2
FLAGB
ON
ON/OFF Control Input, Active High for FPF2024/6/7 and Active LO for FPF2025
Absolute Maximum Ratings
Parameter
Min.
Max.
6
Unit
V
VIN, VOUT, ON, FLAGB to GND
Power Dissipation @ TA = 25°C (Note 1)
Maximum Continuous Switch Current
Operating Temperature Range
Storage Temperature
-0.3
1.2
0.2
125
150
85
W
A
-40
-65
°C
°C
°C/W
V
Thermal Resistance, Junction to Ambient
Electrostatic Discharge Protection
HBM
CDM
5500
1500
V
Note1: Package power dissipation on 1square inch pad, 2 oz. copper board.
Recommended Operating Range
Parameter
Min.
1.6
Max.
5.5
Unit
V
VIN
Ambient Operating Temperature, TA
-40
85
°C
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
3
www.fairchildsemi.com
Electrical Characteristics
VIN = 1.6 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
Basic Operation
Operating Voltage
VIN
1.6
5.5
4
V
IOUT = 0mA, VON Active,
Quiescent Current
Shutdown Current
IQ
1
µA
µA
V
IN = 1.8V (Average)
VON = VIN (FPF2025)
ON = GND (FPF2024/6/7), IOUT = 0
ISHDN
1
V
TA = 25°C, VIN = 5.5V
TA = -40 to +85°C, VIN = 5.5V
TA = 25°C,VIN = 3.3V
TA = -40 to +85°C, VIN = 3.3V
TA = 25°C,VIN = 1.6V
TA = -40 to +85°C, VIN = 1.6V
VIN = 1.6V
215
215
225
225
305
305
315
350
325
360
490
580
120
140
On-Resistance
RON
mΩ
180
0.8
1.5
ON Input Logic High Voltage (ON)
ON Input Logic Low Voltage
VIH
VIL
V
V
VIN = 5.5V
VIN = 1.6V
0.45
0.9
1
VIN = 5.5V
ON Input Leakage
Off Switch Leakage
VON = VIN or GND
µA
µA
ISWOFF
VON = VIN, VOUT = 0V
VIN = 5.5V, ISINK = 1mA
VIN = 1.8V, ISINK = 1mA
VIN = 5.5V, ISOURCE = 1mA, FPF2025
VIN = 1.6V, ISOURCE = 1mA, FPF2025
1
0.1
0.1
0.2
0.3
FLAGB Output Logic Low Voltage
V
5.2
1.2
5.4
FLAGB Output Logic High Voltage
FLAGB Output High Leakage Current
V
1.35
V
IN = 5.5V, Switch on,
1
µA
FPF2024, FPF2026, FPF2027
Protections
Current Limit
ILIM
VIN = 3.3V, VOUT = 3.0V,TA = 25°C
Shutdown Threshold TJ increasing
Return from Shutdown
Hysteresis
100
150
140
130
10
200
mA
°C
Thermal Shutdown
Under Voltage Lockout
Under Voltage Lockout Hysteresis
Dynamic
UVLO
VIN Increasing
1.475
1.525
40
1.575
V
mV
Turn On Time
tON
RL = 500Ω, CL = 0.1µF
RL = 500Ω
70
10
µs
µs
Turn Off Time
tOFF
VOUT Rise Time
tRISE
tBLANK
RL = 500Ω, CL = 0.1µF
FPF2024, FPF2025,FPF2026
30
µs
Over Current Blanking Time
Startup FLAGB Blanking Time
Auto-Restart Time
5
5
10
20
20
ms
ms
ms
ms
ms
tSTART_BLANK FPF2027 (Note2)
10
tRSTRT
FPF2024, FPF2025
35
70
140
514
2
Sleep Mode Duration
Wake-up Mode Duration
Duty Cycle
128.5
0.5
257
1
Wake-up: Sleep Mode Duty Cycle
1:257
Current Limit Response Time
Moderate Over-current condition
RL= 5Ohms
15
µs
Blanking/Auto-Restart Duty Ratio
tBLANK /tRSTRT (internally fixed)
FPF2024, FPF2025
1:7
Note2: FPF2027 has a 10ms Startup FLAGB Blanking Time when the part is turned on via ON pin to ensure transient load currents
settle down.
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
4
www.fairchildsemi.com
Typical Characteristics
70
69
68
67
66
65
64
63
0.3
0.25
V = 5.5V
IN
0.2
0.15
0.1
V = 3.3V
IN
V = 1.6V
IN
0.05
0
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
Temperature (oC)
Temperature (oC)
Figure 1. Shutdown Current vs.Temperature
Figure 2. TRestart vs. Temperature
10.4
10.2
10
1200
1100
1000
900
V = 1.8V
IN
9.8
9.6
9.4
9.2
800
700
600
-50
-25
0
25
50
75
100
-50
-25
0
25
50
75
100
Temperature (oC)
Temperature (oC)
Figure 3. Quiescent Current vs. Temperature
Figure 4. TBlank vs. Temperature
350
300
250
200
150
350
300
250
200
150
V = 1.6 V
IN
V = 1.8 V
IN
85 oC
V = 3.3 V
IN
50 oC
25 oC
V = 5.5 V
IN
0 oC
-25 oC
-40 oC
-50
-25
0
25
50
75
100
1
2
3
4
5
6
Temperature oC
V (V)
IN
Figure 5. RDS(ON) vs. VIN
Figure 6. RDS(ON) vs. Temperature
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
5
www.fairchildsemi.com
Typical Characteristics
160
160
159
158
157
156
155
154
153
-40 oC
158
-25 oC
0 oC
V = 5.5V
IN
156
154
152
25 oC
50 oC
V = 1.6V
IN
85 oC
V = 3.3V
IN
1
2
3
4
5
6
-50
-25
0
25
Temperature (oC)
Figure 8. ILimit vs. Temperature
50
75
100
V (V)
IN
Figure 7. ILimit vs. VIN
2
1.5
1
VIN
2V/DIV
VIN=3.3V
C
C
IN=10uF
OUT=0.1uF
V = 5.5V
RL=500Ω
ON=3.3V
IL
VON
2V/DIV
V
V = 5.5 V
IH
V = 1.6 V
IL
ILOAD
10mA/DIV
0.5
V = 1.6 V
IH
0
VOUT
2V/DIV
-50
-25
0
25
50
75
100
Temperature (oC)
Figure 9. VIH, VIL vs Temperature
200 µs/DIV
Figure 10. FPF2024 TON Response
VDRV
(Note3)
2V/DIV
VIN
2V/DIV
VIN=3.3V
IN=10uF
RL=500Ω
ON=3.3V
C
TBLANK
V
VON
2V/DIV
FLAGB
2V/DIV
VIN=VON=3.3V
C
IN=10uF
ILOAD
100mA/DIV
ILOAD
10mA/DIV
COUT=0.1uF RL=500Ω
VOUT
2V/DIV
VOUT
2V/DIV
100us/DIV
Figure 11. FPF2024 TOFF Response
5 ms/DIV
Figure 12. FPF2024 TBLANK Response
Note3: VDRV signal forces the device to go into overcurrent condition by loading a 7.5Ω.
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
6
www.fairchildsemi.com
Typical Characteristics
VIN=VON=3.3V
VDRV
(Note3)
2V/DIV
VIN
2V/DIV
CIN=10uF
COUT=0.1uF
RL=500Ω
VON
FLAGB
2V/DIV
2V/DIV
TRESTART
ILOAD
100mA/DIV
VIN=VON=3.3V
ILOAD
CIN=10uF
100mA/DIV
C
OUT=10uF
VOUT
2V/DIV
RL=5Ω
VOUT
2V/DIV
10 ms/DIV
50us/DIV
Figure 13. FPF2024 TRESTART Response
Figure 14. FPF2024 Current Limit Response Time
(Output is loaded by 5Ω and COUT = 10uF)
VIN
VIN
2V/DIV
2V/DIV
VON
2V/DIV
VON
2V/DIV
VIN=VON=3.3V
IN=10uF
C
COUT=0.1uF
RL=100Ω
VIN=VON=3.3V
ILOAD
100mA/
DIV
ILOAD
2A/DIV
CIN=10uF
COUT=100uF
RL=5Ω
VOUT
VOUT
2V/DIV
2V/DIV
500us/DIV
20us/DIV
Figure 15. FPF2024 Current Limit Response Time
Figure 16. FPF2024 Short Circuit Response Time
(Output is loaded by 5Ω and COUT = 100uF)
(Output shorted to GND while the switch is in normal operation)
VDRV
(Note3)
VIN/VON
2V/DIV
VIN=VON=3.3V
2V/DIV
VIN=VON=3.3V
IN=10uF
OUT =GND
C
IN=10uF
C
V
COUT=0.1uF
ILOAD
100mA/DIV
RL=100Ω
ILOAD
100mA/DIV
FLAGB
2V/DIV
VOUT
2V/DIV
VOUT
2V/DIV
20us/DIV
10 ms/DIV
Figure 18.FPF2027 Over-Current
Over-Current condition is applied while device in normal operation
(FLAGB inserts immediately and reports the fault condition)
Figure 17. FPF2024 Current Limit Response
(Input and enable pin are tied together and
V
OUT is shorted to GND)
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
7
www.fairchildsemi.com
Typical Characteristics
VIN=3.3V
VON
2V/DIV
VON
2V/DIV
Device is ON
CIN=10uF
COUT=0.1uF
VIN=3.3V
RL=7.5Ω
CIN=10uF
FLAGB
2V/DIV
COUT=10uF
FLAGB
2V/DIV
RL=5Ω
ILOAD
ILOAD
100mA/DIV
100mA/DIV
VOUT
VOUT
2V/DIV
2V/DIV
10 ms/DIV
Figure 19. FPF2027 Startup FLAGB Blanking Time
20ms/DIV
Figure 20. FPF2025 TBLANK and TRESTART
(Active LO Device)
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
8
www.fairchildsemi.com
Description of Operation
On/Off Control
The ON pin controls the state of the switch. The FPF2024-
FPF2027 series features both active high and low
FPF2024-FPF2027 series Full-Function switches are current
limited load switches with ultra-low power consumption. The
core of each device consists of a 230mW P-channel MOSFET
featuring slow turn-on to limit the inrush current, fast turn-off,
current limit, UVLO(under-voltage lockout) and thermal
configurations
to
accommodate
various
application
requirements. FPF2024, FPF2026 and FPF2027 are active high
switches while the FPF2025 is an active low device. Applying a
continuous high or low signal depending on the switch
configuration, will hold the switch in the ON state. The load
switch will move into the OFF state when the ON pin is inactive.
In addition, FPF2026 moves into the OFF state if a current fault
is encountered for longer duration than the Blanking Time. For
all versions, an undervoltage on VIN or a junction temperature in
excess of 140°C overrides the ON control and turns off the
switch.
shutdown protection features and
a FLAGB output that
indicates that a fault condition has occurred.
Some versions in the FPF202x series also feature Current Limit
Blanking and Auto-Restart.
The FPF202x family achieves an ultra-low current consumption
of 1µA through
a
proprietary ”Sleep-Wakeup modes”
implementation. Full functionality is guaranteed for operating
voltages down to 1.6V over the -40°C to +85°C temperature
range.
In addition, a current fault condition longer than the Blanking
Time will cause the switch to turn off in the FPF2024, FPF2025
and FPF2026. The FPF2024 and FPF2025 have an Auto-
Restart feature which will automatically turn the switch on again
after 70ms. For the FPF2026, the ON pin must be toggled to
turn the switch on again. The FPF2027 does not turn off in
response to an over current condition, and remains in a
constant current mode for so long as the ON pin is active, and
the thermal shutdown or UVLO are not activated.
Sleep and Wakeup Mode Description
The ultra-low power consumption of FPF2024-FPF2027 is
achieved through the implementation of proprietary Sleep/
Wakeup modes.
The FPF2024-FPF2027 family turns on in Startup mode where
it checks for potential load current, temperature, and under-
voltage faults for 10ms. If no faults are detected during this
startup period, the FPF2024-FPF2027 goes into a Sleep mode
where it stays for 257ms. At the end of the Sleep period, the
part goes into Wakeup mode to check for any fault condition. If
no fault is detected in 1ms, the part goes back to Sleep mode.
The 1:257 Wakeup/Sleep duty cycle results in an overall
average current consumption of 1 µA (typ).
The ON pin control voltage and VIN pin have independent
recommended operating ranges. The ON pin voltage can be
driven by a voltage level higher than the input voltage.
Fault Reporting
Over-current, input under-voltage, or over-temperature fault
conditions are signaled out by the FLAGB pin going low.
FPF2024, FPF2025 and FPF2026 have a current fault blanking
feature which prevents current faults lasting shorter than the
Blanking Time of 10ms (typ) from triggering the fault signal
(FLAGB) output.
During Sleep mode the thermal and under-voltage conditions
are not monitored to reduce the current consumption of the
device.
The switch current limiting circuitry is active at all times and
protects the FPF2024-FPF2027 against excessive load currents
in all modes.
If the over-current condition persists beyond the Blanking Time,
the FPF2024 and FPF2025 pull the FLAGB pin low and shut the
switch off. If the ON pin is kept active, an Auto-Restart feature
releases the FLAGB pin and turns the switch on again after
70ms.
While in the Wakeup mode, a current fault event will prevent the
part from re-entering into Sleep mode even if input voltage and
temperature faults are not present. In such a case, the part
functions according to its feature set, e.g., it performs its normal
Blanking, Auto-Restart or Latch-off functions as expected. If the
over-current condition is removed from the output, the part will
go back into Sleep mode after 10ms. The representative state
diagrams of the FPF2024-FPF2027 are given in Figure 21,
Figure 22 and Figure 23.
If the over-current condition persists beyond the Blanking Time,
the FPF2026 has a Latch-Off feature which pulls the FLAGB pin
low and shuts the switch off. The switch is kept off and the
FLAGB pin is kept low until the ON pin is toggled.
The FPF2027 responds to an overload condition by immediately
pulling the FLAGB pin low and the switch remains in constant
current mode until the output overload condition is removed.
The FPF2027 has a Start-Up Blanking feature which prevents
current faults related to start-up transients from triggering the
FLAGB output. The Startup Blanking feature is effective for the
first 10ms (typ) following device turn-on via ON pin.
The ultra-low quiescent current consumption of 1µA along with
the very-low minimum operating voltage of 1.6V, make the
FPF2024-FPF2027 an ideal full-function load switch for ultra-
portable applications.
The FPF2024, FPF2026 and FPF2027 have an open-drain
MOSFET FLAGB output which requires a pull-up resistor
between VIN and FLAGB.
A 100KΩ pull up resistor is
recommended. The FPF2025 has a CMOS FLAGB output and
does not require a pull-up resistor. During shutdown, the pull-
down on FLAGB is disabled to reduce current draw from the
supply.
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
9
www.fairchildsemi.com
Current Limiting
The current limit function ensures that the current through the
switch does not exceed a maximum value while not limiting at
less than a minimum value. The minimum current at which the
parts will limit the load current is internally set to 100mA.
The switch current limiting circuitry is active at all times(Sleep
and Wakeup mode) and protects the FPF2024-FPF2027
against excessive load currents in all modes. The proprietary
current limiting circuit responds to an over-current condition in
15 µs (typ).
Undervoltage Lockout (UVLO)
The undervoltage lockout feature 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 and will limit current over-shoots. The UVLO feature
is disabled during Sleep mode. If device is in the UVLO
condition, FLAGB goes low and indicates the fault. If the input
voltage goes below UVLO voltage but remains above 1.3V (typ)
during Sleep mode, the switch is kept on until the next Wakeup
cycle, where the UVLO violation will be detected. If the input
voltage falls below 1.3V in Sleep mode, the switch is
immediately turned off.
Thermal Shutdown
The Thermal Shutdown protects the device from internally or
externally generated excessive temperatures. The Thermal
shutdown feature is disabled during Sleep mode. However,
excessive load currents that may result in high power dissipa-
tion will be detected during Sleep mode and will activate the full-
function Wakeup mode, which has thermal shutdown protection.
During an over-temperature condition the FLAGB is pulled low
and the 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 (typ)
thermal hysteresis is implemented between thermal shutdown
entry and exit temperatures.
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
10
www.fairchildsemi.com
Description of Operation cont.
State Diagram for the part options with Blanking and Auto-Restart (FPF2024/5)
OFF
Notes:
All States return to OFF when ON is removed.
Typical timing values are shown.
Key: I=Load Switch current, V=Input Voltage, T=Die Temperature
ON
I FAULT
(V OR T)
FAULT
STARTUP&
BLANKING
(Full-feature
for 10ms)
SLEEP
(I AND V AND T)
OK
(Monitor SW
current only
for 257ms)
I FAULT
END 257ms
I FAULT
(I AND V AND T)
OK
END 70ms
AUTO-
RESTART
70ms
WAKEUP
(Full-feature
for 1ms)
(V OR T)
FAULT
Figure 21. Representative State Diagram of FPF2024/5
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
11
www.fairchildsemi.com
Description of Operation cont.
State Diagram for the part options with Blanking only(no Auto-Restart -FPF2026)
OFF
Notes:
All States return to OFF when ON is removed.
Typical timing values are shown .
Key: I=Load Switch current, V=Input Voltage, T=Die Temperature
I FAULT
ON
I FAULT
STARTUP &
BLANKING
(Full-feature
for 10ms)
SLEEP
(I AND V AND T)
OK
(Monitor SW
current only
for 257ms)
I OR V OR T)
FAULT
END 257ms
I FAULT
(I AND V AND T)
OK
WAKEUP
(Full-feature
for 1ms)
(V OR T)
FAULT
Figure 22. Representative State Diagram of FPF2026
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
12
www.fairchildsemi.com
Description of Operation cont.
State Diagram for the part options with no Blanking (FPF2027)
OFF
Notes:
All States return to OFF when ON is removed.
Typical timing values are shown .
Key: I=Load Switch current, V=Input Voltage, T=Die Temperature
ON
I FAULT
STARTUP&
SLEEP
BLANKING
(Full-feature
for 10ms)
(I AND V AND T)
OK
(Monitor SW
current only
for 257ms)
I OR V OR T)
FAULT
END 257ms
I FAULT
(I AND V AND T)
OK
WAKEUP
(Full-feature
for 1ms)
(V OR T)
FAULT
Figure 23. Representative State Diagram of FPF2027
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
13
www.fairchildsemi.com
Application Information
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. The FPF2024-FPF2027
series feature a slow turn-on to limit the inrush current and
Improving Thermal Performance
An improper layout could result in higher junction temperature
and ultimately trigger the thermal shutdown protection feature.
This concern applies particularly significant for the FPF2027
where the switch is in constant current mode in the overload
conditions.
requires a smaller input capacitor. A 1uF ceramic capacitor, CIN
placed close to the pins is typically sufficient. Higher values of
IN can be used to further reduce the voltage drop.
,
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.
C
Output Capacitor
NC pin can be connected to the GND plane to improve
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
FPF2024, FPF2025 and FPF2026, 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 turning-off the switch. The maximum output
capacitance can be determined from the following formula:
thermal performance.
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 24 provides each pin with
adequate copper so that heat may be transferred out of the
device as efficiently as possible. The low-power FLAGB and
ON pin traces may be laid-out to maximize the area available
to the ground pad.
I
LIM(Max) x tBLANK(Min)
VIN
COUT(Max)
=
Placing the input and output capacitors as close to the device
as possible also contributes to heat dissipation, particularly
during high load currents.
Power Dissipation
During normal operation as a switch, the power dissipation is
small and has little effect on the operating temperature of the
part. The maximum power dissipation while switch is in normal
operation occurs just before a part enters the current limit. This
may be calculated using the formula bellow:
FPF202X Demo Board
FPF202X Demo board has components and circuitry to
demonstrate the functions and features of the FPF202X load
switch family. An N-Channel MOSFET(Q), in series with a 7.5Ω
resistor, are connected between VOUT and the GND pin of the
device. By turning on the Q transistor, the 7.5Ω is loaded to the
output voltage and simulates an over-current condition. The R2
resistor is connected between FLAGB pin and input voltage as
pull-up resistor for FPF2024, FPF2026 and FPF2027 devices.
The FPF2025 does not require a pull-up resistor due to its
CMOS output structure.
P
Max(Normal Operation) = (ILIM(Max))2xRON(Max)
= (0.2)2 x 0.58 = 23.2 mW, for VIN=1.6V
If the part goes into current limit, the maximum power
dissipation occurs when the output of switch is shorted to
ground. For the FPF2024 and FPF2025, the power dissipation
will scale with the Auto-Restart Time, tRSTRT, and the Over
Current Blanking Time, tBLANK. In this case the maximum power
dissipated for the FPF2024 and FPF2025 is:
The thermal performance of the board is improved using the
techniques recommended in the layout recommendations
section of datasheet.
tBLANK
x VIN(Max) x ILIM(Max)
PMax(Current limit)
=
=
tBLANK + tRSTRT
10
10 + 70
x 5.5 x 0.2 =137 mW
Take 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 will have no affect
until the junction temperature drops below the thermal
shutdown exit temperature. For the FPF2027, a short on the
output will cause the part to operate in a constant current state
dissipating a worst case power of:
PMax = VIN(Max) X ILIM(Max) = 5.5X0.2 =1.1 W
Output of FPF2027 is shorted to GND.
Figure 24. FPF202X proper layout
This power dissipation is significant enough that it will activate
the thermal shutdown protection, and the part will cycle in and
out of thermal shutdown so long as the ON pin is active and the
output short is present.
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
14
www.fairchildsemi.com
Figure 28. TOP, SST and SMT
Figure 25. Top Layer
Figure 26. Bottom Layer
Figure 27. SST
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
15
www.fairchildsemi.com
Dimensional Outline and Pad Layout
Product
D
E
X
Y
FPF2024/5/6/7
1.500+/- 0.030
1.000 +/-0.030
0.240
0.240
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
16
www.fairchildsemi.com
TRADEMARKS
The following includes registered and unregistered trademarks and service marks, owned by Fairchild Semiconductor and/or its global subsidianries, and is
not intended to be an exhaustive list of all such trademarks.
®
®
Build it Now™
CorePLUS™
CorePOWER™
CROSSVOLT™
CTL™
FRFET
Programmable Active Droop™
QFET
QS™
Quiet Series™
RapidConfigure™
The Power Franchise
®
Global Power ResourceSM
Green FPS™
Green FPS™ e-Series™
GTO™
IntelliMAX™
ISOPLANAR™
MegaBuck™
MICROCOUPLER™
MicroFET™
MicroPak™
MillerDrive™
MotionMax™
TinyBoost™
TinyBuck™
Current Transfer Logic™
®
TinyLogic
®
EcoSPARK
™
TINYOPTO™
TinyPower™
TinyPWM™
TinyWire™
µSerDes™
EfficentMax™
EZSWITCH™ *
™
Saving our world, 1mW at a time™
Saving our world, 1W at a time™
Saving our world, 1kW at a time™
SmartMax™
SMART START™
®
SPM
®
Fairchild
Motion-SPM™
OPTOLOGIC
STEALTH™
SuperFET™
SuperSOT™-3
SuperSOT™-6
SuperSOT™-8
SupreMOS™
®
®
®
Fairchild Semiconductor
FACT Quiet Series™
UHC
®
OPTOPLANAR
Ultra FRFET™
UniFET™
VCX™
®
®
FACT
FAST
®
FastvCore™
VisualMax™
PDP SPM™
Power-SPM™
PowerTrench
®
FlashWriter
FPS™
*
SyncFET™
®
®
F-PFS™
®
* EZSWITCH™ and FlashWriter are trademarks of System General Corporation, used under license by Fairchild Semiconductor.
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE
RELIABILITY, FUNCTION, OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY
PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
THESE SPECIFICATIONS DO NOT EXPAND THE TERMS OF FAIRCHILD’S WORLDWIDE TERMS AND CONDITIONS, SPECIFICALLY THE WARRANTY
THEREIN, WHICH COVERS THESE PRODUCTS.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE
EXPRESS WRITTEN APPROVAL OF FAIRCHILD SEMICONDUCTOR CORPORATION.
As used herein:
1. Life support devices or systems are devices or systems which, (a) are
intended for surgical implant into the body or (b) support or sustain life,
and (c) whose failure to perform when properly used in accordance with
instructions for use provided in the labeling, can be reasonably
expected to result in a significant injury of the user.
2. A critical component in any component of a life support, device, or
system whose failure to perform can be reasonably expected to cause
the failure of the life support device or system, or to affect its safety or
effectiveness.
ANTI-COUNTERFEITING POLICY
Fairchild Semiconductor Corporation’s Anti-Counterfeiting Policy. Farichild’s Anti-Counterfeiting Policy is also stated on our external website,
www.fairchildsemi.com, under Sales Support.
Counterfeiting of semiconductor parts is a growing problem in the industry. All manufactures of semiconductor products are experiencing counterfeiting of their
parts. Customers who inadvertently purchase counterfeit parts experience many problems such as loss of brand reputation, substandard performance, failed
application, and increased cost of production and manufacturing delays. Fairchild is taking strong measures to protect ourselves and our customers from the
proliferation of counterfeit parts. Farichild strongly encourages customers to purchase Farichild parts either directly from Fairchild or from Authorized Fairchild
Distributors who are listed by country on our web page cited above. Products customers buy either from fairchild directly or from Authorized Fairchild
Distributors are genuine parts, have full traceability, meet Fairchild’s quality standards for handing and storage and provide access to Farichild’s full range of
up-to-date technical and product information. Fairchild and our Authorized Distributors will stand behind all warranties and will appropriately address and
warranty issues that may arise. Fairchild will not provide any warranty coverage or other assistance for parts bought from Unauthorized Sources. Farichild is
committed to committed to combat this global problem and encourage our customers to do their part in stopping this practice by buying direct or from authorized
distributors.
PRODUCT STATUS DEFINITIONS
Definition of Terms
Datasheet Identification
Product Status
Definition
Datasheet contains the design specifications for product development. Specifications may change
in any manner without notice.
Advance Information
Formative / In Design
Datasheet contains preliminary data; supplementary data will be published at a later date. Fairchild
Semiconductor reserves the right to make changes at any time without notice to improve design.
Preliminary
First Production
Full Production
Not In Production
Datasheet contains final specifications. Fairchild Semiconductor reserves the right to make
changes at any time without notice to improve the design.
No Identification Needed
Obsolete
Datasheet contains specifications on a product that is discontinued by Fairchild Semiconductor.
The datasheet is for reference information only.
Rev. I36
©2008 Fairchild Semiconductor Corporation
FPF2024/5/6/7 Final. B
17
www.fairchildsemi.com
相关型号：
©2020 ICPDF网 联系我们和版权申明