FPF2187 [FAIRCHILD]
Buffer/Inverter Based Peripheral Driver, 1 Driver, 0.6A, PBGA6, 1.00 X 1.50 MM, ROHS COMPLIANT, CSP-6;型号: | FPF2187 |
厂家: | FAIRCHILD SEMICONDUCTOR |
描述: | Buffer/Inverter Based Peripheral Driver, 1 Driver, 0.6A, PBGA6, 1.00 X 1.50 MM, ROHS COMPLIANT, CSP-6 驱动 接口集成电路 |
文件: | 总14页 (文件大小:562K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
October 2007
FPF2180/82/83/84/86/87
Full Function Load Switch with Reverse Current Blocking
Features
General Description
¢ 1.8 to 5.5V Input Voltage Range
The FPF2180/82/83/84/86/87 is a series of load switches which
provides full protection to systems and loads which may
encounter large current conditions. These devices contain a
55mꢁ current-limited P-channel MOSFET which can operate
over an input voltage range of 1.8-5.5V. Internally, current is
prevented from flowing when the MOSFET is off and the output
voltage is higher than the input voltage. Switch control is by a
logic input (ON) capable of interfacing directly with low voltage
control signals. Each part contains thermal shutdown protection
which shuts off the switch to prevent damage to the part when a
continuous over-current condition causes excessive heating.
¢ Controlled Turn-On
¢ 200mA and 400mA Current Limit Options
¢ Undervoltage Lockout
¢ Thermal Shutdown
¢ <2ꢀA Shutdown Current
¢ Auto Restart
¢ Fast Current limit Response Time
¢ 5ꢀs to Moderate Over Currents
¢ 30ns to Hard Shorts
When the switch current reaches the current limit, the part
operates in a constant-current mode to prohibit excessive
currents from causing damage. For the FPF2180/82/84/86, if
the constant current condition still persists after 30ms, the part
will shut off the switch and pull the fault signal pin (FLAGB) low.
The FPF2180/84 have an auto-restart feature which will turn the
switch on again after 450ms if the ON pin is still active. The
FPF2182/86 do not have this auto-restart feature so the switch
will remain off until the ON pin is cycled. For the FPF2183/87, 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. The minimum
current limit is 200mA for the FPF2180/82/83 while that for the
FPF2184/86/87 is 400mA.
¢ Fault Blanking
¢ Reverse Current Blocking
¢ Power Good Function
¢ RoHS Compliant
Applications
¢ PDAs
¢ Cell Phones
¢ GPS Devices
¢ MP3 Players
¢ Digital Cameras
¢ Peripheral Ports
¢ Hot Swap Supplies
These parts are available in a space-saving 6 ball advanced.
Pb-Free 1 x 1.5 mm CSP package.
Pin 1
ON
VIN
FLAGB
VOUT
PGOOD
GND
TOP
BOTTOM
Ordering Information
Current Limit
Blanking Time
[ms]
Auto-Restart
ON Pin
Current Limit
Part
Time
[ms]
Top Mark
[mA]
Activity
FPF2180
FPF2182
FPF2183
FPF2184
FPF2186
FPF2187
200/300/400
200/300/400
200/300/400
400/600/800
400/600/800
400/600/800
15/30/60
15/30/60
0
225/450/900
Active HI
Active HI
Active HI
Active HI
Active HI
Active HI
A
B
C
D
E
F
NA
NA
15/30/60
15/30/60
0
225/450/900
NA
NA
©2007 Fairchild Semiconductor Corporation
FPF2180/82/83/84/86/87 Rev. F
1
www.fairchildsemi.com
Typical Application Circuit
TO LOAD
V
V
IN
OUT
FPF2180/2/3/4/6/7
FLAGB
PGOOD
ON
OFF ON
GND
Functional Block Diagram
V
IN
UVLO
REVERSE
CONTROL
LOGIC
ON
CURRENT
BLOCKING
THERMAL
SHUTDOWN
CURRENT
LIMIT
V
OUT
FLAGB
PGOOD
GND
2
www.fairchildsemi.com
FPF2180/82/83/84/86/87 Rev. F
Pin Configuration
A2
B2
C2
A1
B1
C1
1.0 x 1.5 CSP Bottom View
Pin Description
Pin
Name
Function
Power Good output: Open drain output which indicate that output voltage has reached 90%
of input voltage
C1
PGOOD
B2
B1
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.
A1
FLAGB
C2
A2
GND
ON
Ground
ON Control Input
Absolute Maximum Ratings
Parameter
Min.
-0.3
Max.
6
Unit
V
V
, V
, ON, FLAGB, PGOOD to GND
OUT
IN
Power Dissipation @ T = 25°C (Note 1)
1.2
W
A
Operating Temperature Range
Storage Temperature
-40
-65
125
150
85
°C
°C
Thermal Resistance, Junction to Ambient
Electrostatic Discharge Protection
°C/W
V
HBM
MM
8000
400
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 =3.3VandT =25°C.
A IN A
IN
Parameter
Symbol
Conditions
Min.
Typ.
Max. Units
Basic Operation
Operating Voltage
V
1.8
5.5
V
IN
V
V
V
= 1.8V
= 3.3V
= 5.5V
70
75
85
55
IN
IN
IN
I
V
= 0mA
= V
IN
OUT
Quiescent Current
On-Resistance
I
ꢀA
Q
ON
T = 25°C, I
= 200mA
OUT
80
A
R
mꢁ
ON
T = -40 to +85°C, I
= 200mA
135
A
OUT
Note 1: Package power dissipation on 1square inch pad, 2 oz. copper board.
3
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FPF2180/82/83/84/86/87 Rev. F
Electrical Characteristics Cont.
V
= 1.8 to 5.5V, T = -40 to +85°C unless otherwise noted. Typical values are at V = 3.3V and T = 25°C
.
IN
A
IN
A
Parameter
Symbol
Conditions
Min.
Typ.
Max. Units
V
V
V
V
V
= 1.8V
= 5.5V
= 1.8V
= 5.5V
0.8
IN
ON Input Logic High Voltage (ON)
V
V
IH
1.4
IN
0.5
V
IN
ON Input Logic Low Voltage
ON Input Leakage
V
IL
1.0
IN
= V or GND
-1
-2
0
1
2
ꢀA
ꢀA
ON
IN
V
V
= 0V, V = 5.5V,
IN
= short to GND
ON
V
Shutdown Current
IN
OUT
V
V
V
= 5V, I
= 10mA
SINK
0.05
0.12
0.2
0.3
1
IN
IN
IN
FLAGB Output Logic Low Voltage
V
= 1.8V, I
= 10mA
SINK
FLAGB Output High Leakage Current
PGOOD Threshold Voltage
= V = 5V
ꢀA
ON
90
1
%
PGOOD Threshold Voltage
Hysteresis
%
V
V
= 5V, I
= 10mA
SINK
0.05
0.12
0.2
0.3
V
V
IN
PGOOD Output Logic Low Voltage
= 1.8V, I
= 10mA
IN
SINK
PGOOD Output High Leakage
Current
V
= 5V, Switch ON
1
ꢀA
IN
Reverse Block
V
V
= 0V, V
= short to GND
= 5.5V,
OUT
ON
V
Shutdown Current
-2
2
ꢀA
OUT
IN
Reverse Breakdown Voltage
V
V
= V = 0V, I = 200ꢀA
OUT
9
V
breakdown
IN
ON
Protections
FPF2180
FPF2182
FPF2183
200
400
300
600
400
800
V
V
= 3.3V,
IN
Current Limit
I
mA
LIM
= 3.0V
OUT
FPF2184
FPF2186
FPF2187
Shutdown Threshold T increasing
140
130
10
°C
°C
°C
V
J
Thermal Shutdown
Return from Shutdown
Hysteresis
Under Voltage Lockout
Under Voltage Lockout Hysteresis
Dynamic
V
V
Increasing
IN
1.55
1.65
50
1.75
UVLO
mV
Delay On Time
td
R =500ꢁ, C =0.1ꢀF
20
20
ꢀs
ꢀs
ꢀs
ꢀs
ꢀs
ꢀs
ON
L
L
V
Rise Time
t
t
R =500ꢁ, C =0.1ꢀF
L L
OUT
R
Turn On Time
Delay Off Time
R =500ꢁ, C =0.1ꢀF
40
ON
L
L
td
R =500ꢁ, C =0.1ꢀF
15
OFF
L
L
V
Fall Time
t
R =500ꢁ, C =0.1ꢀF
110
125
OUT
F
L
L
Turn Off Time
t
R =500ꢁ, C =0.1ꢀF
L L
OFF
FPF2180, FPF2182, FPF2184,
FPF2186
Over Current Blanking Time
Auto-Restart Time
t
t
15
30
450
5
60
ms
ms
ꢀs
BLANK
FPF2180,FPF2184
225
900
RSTRT
V
= V = 3.3V. Moderate
ON
IN
Over-Current Condition
Short Circuit Response Time
V
= V = 3.3V. Hard Short
30
ns
IN
ON
4
www.fairchildsemi.com
FPF2180/82/83/84/86/87 Rev. F
Typical Characteristics
95
1.7
1.5
1.3
1.1
0.9
0.7
0.5
0.3
0.1
-0.1
VON=0V
VON=VIN
90
85
80
75
70
65
1
2
3
4
5
6
7
1
2
3
4
5
6
7
SUPPLY VOLT AGE (V)
SUPPLYVOLTAGE (V)
Figure 1. Quiescent Current vs. Input Voltage
Figure 2. Quiescent Current vs. Input Voltage
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
110
105
100
95
VIN=5.5V
VIN=3.3V
90
85
80
VIN=1.8V
75
70
65
60
55
50
-65
-40
-15
10
35
60
85
110
135
1
2
3
4
5
6
T J, JUNCTION TEM PERAT URE (oC)
VIN, SUPPLY VOLTAGE (V)
Figure 3. Quiescent Current vs. Temperature
Figure 4. V
High Voltage vs. Input Voltage
ON
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
340
310
280
250
220
190
160
FPF2180/82/83
VONL(VIL
)
0
1
2
3
4
5
6
1
2
3
4
5
6
(VIN-VOUT), SUPPLY VOLTAGE(V)
VIN, SUPPLY VOLTAGE (V)
Figure 5. V
Low Voltage vs. Input Voltage
Figure 6. Current Limit vs. Output Voltage
ON
5
www.fairchildsemi.com
FPF2180/82/83/84/86/87 Rev. F
Typical Characteristics
650
300
295
290
285
280
275
FPF2184/86/87
FPF2180/82/83
600
550
500
450
400
350
-65
-40
-15
10
35
60
85
110
135
0
1
2
3
4
5
6
TJ, JUNCTION TEMPERATURE (oC)
(V -VOUT), SUPPLYVOLTAGE(V)
IN
Figure 7. Current Limit vs. Output Voltage
Figure 8. Current Limit vs. Temperature
600
595
590
585
580
575
570
565
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1
FPF2184/86/87
0.9
0.8
0.7
-65
-40
-15
10
35
60
85
110
135
1
2
3
4
5
6
TJ, JUNCTION TEMPERATURE (oC)
VIN, SUPPLY VOLTAGE(V)
Figure 9. Current Limit vs. Temperature
Figure 10. R vs. V
ON IN
2.2
1000
100
10
Vin = 3.3V
RL = 500 Ohms
Cout = 0.1uF
2
1.8
1.6
1.4
1.2
1
VIN=1.8V
TOFF
VIN=3.3V
TON
0.8
0.6
0.4
VIN=5.5V
-65
-40
-15
10
35
60
85
110
135
-65
-40
-15
10
35
60
85
110
135
TJ, JUNCTION TEMPERATURE (oC)
TJ, JUNCTION TEMPERATURE (oC)
Figure 11. R
vs. Temperature
Figure 12. T
/ T
vs. Temperature
ON
ON
OFF
6
www.fairchildsemi.com
FPF2180/82/83/84/86/87 Rev. F
Typical Characteristics
1000
495
480
465
450
435
420
405
Vin = 3.3V
RL = 0.5K
CL = 0.1uF
TFALL
100
TRISE
10
1
-65
-40
-15
10
35
60
85
110
135
-65
-40
-15
10
35
60
85
110
135
TJ, JUNCTION TEMPERATURE (oC)
TJ, JUNCTION TEMPERATURE (oC)
Figure 13. T
/ T
vs. Temperature
Figure 14. T
vs. Temperature
RISE
FALL
RESTART
35
33
31
29
27
25
V
C
C
= 10ꢀF
IN
IN
2V/DIV
= 0.1ꢀF
OUT
R = 500ꢁ
L
V
= 3.3V
IN
V
ON
2V/DIV
I
OUT
10mA/DIV
V
OUT
2V/DIV
-65
-40
-15
10
35
60
85
110
135
TJ, JUNCTION TEMPERATURE (oC)
200ꢀs/DIV
Figure 15. T
vs. Temperature
Figure 16. T
Response
ON
BLANK
V
IN
V
IN
2V/DIV
C
C
= 10ꢀF
IN
2V/DIV
= 0.1ꢀF
C
V
= 10ꢀF
= 3.3V
OUT
IN
R = 500ꢁ
L
IN
V
ON
V
OUT
V
= 3.3V
IN
2V/DIV
2V/DIV
I
I
OUT
OUT
5A/DIV
10mA/DIV
V
OUT
2V/DIV
100ꢀs/DIV
20ꢀs/DIV
Figure 17. T
Response
Figure 18. Short Circuit Response Time
(Output shorted to ground)
OFF
7
www.fairchildsemi.com
FPF2180/82/83/84/86/87 Rev. F
Typical Characteristics
V
ON
2V/DIV
V
= V
ON
IN
2V/DIV
V
IN
2V/DIV
I
I
OUT
OUT
500mA/DIV
C
V
= 10ꢀF
500mA/DIV
IN
C
V
= 10ꢀF
= V
= 3.3V
IN
IN
ON
= V = 3.3V
C
= 0.1uF
IN
ON
OUT
V
OUT
V
= GND
OUT
2V/DIV
50ꢀs/DIV
100ꢀs/DIV
Figure 20. Current Limit Response Time
Figure 19. Current Limit Response Time
(Switch is powered to a short)
(Output is loaded by 2.2ꢁ, C = 0.1ꢀF)
OUT
V
ON
V
IN
C
C
= 10ꢀF
2V/DIV
IN
5V/DIV
= 0.1ꢀF
OUT
R = 500ꢁ
L
V
IN
V
= 5.5V
IN
V
ON
2V/DIV
5V/DIV
∆ = 4.5V
I
OUT
V
OUT
500mA/DIV
C
= 10ꢀF
5V/DIV
IN
V
C
= V
= 10uF
OUT
= 3.3V
IN
ON
V
OUT
PGOOD
5V/DIV
2V/DIV
50ꢀs/DIV
Figure 21. Current Limit Response Time
20ꢀs/DIV
Figure 22. PGOOD Response
(Output is loaded by 2.2ꢁ, C
= 10ꢀF)
OUT
2
2
V
DRV
V
DRV
2V/DIV
2V/DIV
T
V
RESTART
FLAGB
V
FLAGB
2V/DIV
2V/DIV
I
OUT
C
C
= 10ꢀF
= 0.1ꢀF
C
C
= 10ꢀF
IN
OUT
IN
I
OUT
500mA/DIV
= 0.1ꢀF
OUT
500mA/DIV
T
BLANK
R = 500ꢁ
R = 500ꢁ
L
L
V
OUT
V
OUT
V
= 3.3V
IN
V
= 3.3V
IN
2V/DIV
2V/DIV
100ms/DIV
10ms/DIV
Figure 23. T
Response
Figure 24. T
Response
RESTART
BLANK
Note 2: V
signal forces the device to go into overcurrent condition by loading a 2.2ꢁ resistor.
DRV
8
www.fairchildsemi.com
FPF2180/82/83/84/86/87 Rev. F
Typical Characteristics
V
ON
2V/DIV
C
C
= 10ꢀF
IN
V
IN
= 150ꢀF
OUT
2V/DIV
R = 8.2ꢁ
L
V
= 3.3V
2
IN
1
3
I
OUT
500mA/DIV
V
OUT
2V/DIV
500ꢀs/DIV
Figure 25. Switch is turned on into a large output capacitor
1.Short circuit detection.
When the output voltage is below VSCTH=1.1V, the
current limit value is set at 62.5% of the current limit
value.
2. Current limit condition.
Due to the large charging current of the output capacitor
the load switch is still in the current limiting mode.
3. Normal operation.
Output current is below the current limit value
9
www.fairchildsemi.com
FPF2180/82/83/84/86/87 Rev. F
drops below VSCTH, short circuit detection threshold voltage,
the current limit value re-conditioned and short circuit current
limit value is decreased to 62.5% of the current limit value. This
keeps the power dissipation of the part below a certain limit
even at dead short conditions at 5.5V input voltage. The VSCTH
value is set to be 1V. At around 1.1V of output voltage the
switch is removed from short circuit current limiting mode and
the current limit is set to the current limit value.
Description of Operation
The FPF2180/82/83/84/86/87 are current limited 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
55mꢁ P-channel MOSFET and
a controller capable of
functioning over a wide input operating range of 1.8-5.5V. The
controller protects against system malfunctions through current
limiting, under-voltage lockout and thermal shutdown. The
current limit is preset for either 200mA or 400mA.
Under-Voltage Lockout
The under-voltage lockout turns-off the switch if the input
voltage drops below the under-voltage lockout threshold. With
the ON pin active the input voltage rising above the
under-voltage lockout threshold will cause a controlled turn-on
of the switch which limits current over-shoots.
On/Off Control
The ON pin controls the state of the switch. Activating ON
continuously holds the switch in the on state so long as there is
no under-voltage on V or a junction temperature in excess of
IN
140°C. ON is active HI and has a low threshold making it
capable of interfacing with low voltage signals. In addition,
excessive currents will cause the switch to turn off for FPF2180/
82 and FPF2184/86. The FPF2180/84 have an Auto-Restart
feature which will automatically turn the switch on again after
450ms. For the FPF2182/86, the ON pin must be toggled to
turn-on the switch again. The FPF2183/87 do not turn off in
response to a over current condition but instead remain operat-
ing in a constant current mode so long as ON is active and the
thermal shutdown or under-voltage lockout have not activated.
Thermal Shutdown
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.
Reverse Current Blocking
The entire FPF2180/82/83/84/86/87 family has a Reverse
Current Blocking feature that protects input source against
current flow from output to input. For a standard USB power
design, this is an important feature which protects the USB host
Fault Reporting
Upon the detection of an over-current, an input under-voltage,
or an over-temperature condition, the FLAGB signals the fault
mode by activating LO. For the FPF2180/82/84/86, the FLAGB
goes LO at the end of the blanking time while FLAGB goes LO
immediately for the FPF2183/87. FLAGB remains LO through
the Auto-Restart Time for the FPF2180/84. For the
FPF2182/86, FLAGB is latched LO and ON must be toggled to
release it. With the FPF2183/87, 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
from being damaged due to reverse current flow on V
.
BUS
When the load switch is OFF, no current flows from the output to
the input. If the switch is turned on and the output voltage is
greater than input voltage this feature is activated and turns off
the switch. This will prevent any current flow from output to
input. The reverse current blocking feature will be deactivated if
the V
- V is smaller than a typically 50mV threshold.
OUT
IN
resistor between
V
and FLAGB. During shutdown, the
During this time some current (50mV/R ) will flow from the
IN
ON
pull-down on FLAGB is disabled to reduce current draw from
the supply.
output to input until input voltage become greater than output
voltage. The FLAGB operation is independent of the Reverse
Current blocking and will not report a fault condition if this
feature is activated.
Current Limiting
The current limit guarantees that the current through the switch
doesn't exceed a maximum value while not limiting at less than
a minimum value. For the FPF2180/82/83 the minimum current
is 200mA and the maximum current is 400mA and for the
FPF2184/86/87 the minimum current is 400mA and the
maximum current is 800mA. The FPF2180/82/84/86 have a
blanking time of 30ms, nominally, during which the switch will
act as a constant current source. At the end of the blanking
time, the switch will be turned-off and the FLAGB pin will
activate to indicate that current limiting has occurred. The
FPF2183/87 have no current limit blanking period so
immediately upon a current limit condition FLAGB is activated.
These parts will remain in a constant current state until the ON
pin is deactivated or the thermal shutdown turns-off the switch.
Timing Diagram
90%
V
ON
10%
90%
90%
V
OUT
10%
10%
tR
tF
tdON
tdOFF
tON
tOFF
where:
td = Delay On Time
ON
For preventing the switch from large power dissipation during
heavy load a short circuit detection feature is introduced. Short
circuit condition is detected by observing the output voltage.
The switch is put into short circuit current limiting mode if the
switch is loaded with a heavy load. When the output voltage
t
t
td
t = V
t
= V
Rise Time
R
OUT
= Turn On Time
ON
= Delay Off Time
OFF
Fall Time
F
OUT
= Turn Off Time
OFF
10
www.fairchildsemi.com
FPF2180/82/83/84/86/87 Rev. F
Application Information
Typical Application
LOAD
V
V
OUT
IN
FPF2180/2/3/4/6/7
Typical value = 100Kꢁ
OFF ON
C1 = 0.1ꢀF
R1 = 100Kꢁ
C2 = 0.1ꢀF
Battery
1.8V-5.5V
PGOOD
ON
FLAGB
R2 = 499ꢁ
GND
Larger value of C1
is needed for long
supply traces.
When using the FPF2182/86, attention must be given to the
manual resetting of the part. Continuously resetting the part at a
high duty cycle when a short on the output is present can cause
the temperature of the part to increase. The junction
temperature will only be allowed to increase to the thermal shut-
down threshold. Once this temperature has been reached, tog-
gling ON will not turn-on the switch until the junction
temperature drops. For the FPF2180/84, a short on the output
will cause the part to operate in a constant current state
dissipating a worst case power as calculated in (3) until the ther-
mal shutdown activates. It will then cycle in and out of thermal
shutdown so long as the ON pin is active and the short is
present.
Input Capacitor
To limit the voltage drop on the input supply caused by transient
in-rush currents when the switch turns-on into a discharged load
capacitor or a short-circuit, a capacitor needs to be placed
between V and GND. A 0.1ꢀF ceramic capacitor, C , placed
IN
IN
close to the pins is usually sufficient. Higher values of C can
be used to further reduce the voltage drop.
IN
Output Capacitor
A 0.1uF capacitor C
, should be placed between V
and
OUT
OUT
GND. This capacitor will prevent parasitic board inductances
from forcing V below GND when the switch turns-off. For the
OUT
FPF2180/82/84/86, the total output capacitance needs to be
kept below a maximum value, C (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,
Board Layout
OUT
For 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 short-circuit
I
(max) x t
(min)
LIM
BLANK
operation. Using wide traces for V , V
minimize parasitic electrical effects along with minimizing the
case to ambient thermal impedance.
and GND will help
(1)
IN
OUT
C
=
OUT(max)
V
IN
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 parts with the higher current limits will dissipate the
most power and that will only be,
2
2
P = (I ) x R
= (0.8) x 0.055 = 35.2mW
ON
(2)
LIM
If the part goes into current limit the maximum power dissipation
will occur when the output is shorted to ground. For the
FPF2180/84, the power dissipation will scale by the
Auto-Restart Time, t
, and the Over Current Blanking Time,
RSTRT
t
, so that the maximum power dissipated is,
BLANK
t
BLANK
P(max) =
x V (max) x I (max)
IN LIM
t
+ t
RSTRT
BLANK
30
=
x 5.5 x 0.8 = 275mW
(3)
30 + 450
11
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FPF2180/82/83/84/86/87 Rev. F
Application Notes
Startup Power Sequence
To Load
V
V
FPF218X
OUT
IN
PGOOD
ON
V
IN1
FLAGB
OFF ON
GND
100Kꢁ
To Load
V
V
FPF218X
OUT
IN
PGOOD
ON
V
IN2
FLAGB
GND
100Kꢁ
Power good function in sequential startup. No battery is loaded to the output
Power Good
Sequential Startup using Power Good
FPF218X family has a "Power Good" feature. PGOOD pin is an
open-drain MOSFET which asserts high when the output
voltage reaches 90% of the input voltage.
The power good pin can be connected to another load switch's
enable pin to implement sequential startup. PGOOD pin asserts
low when the load switch is OFF. This feature allows driving a
subsequent circuit. The diagram illustrates power good function
in sequential startup. As the VOUT1 of the first load switch
starts to ramp to the 90% of its input voltage the second switch
remains in OFF state. Whereas the VOUT1 passes the 90%
threshold, power good signal becomes active and asserts high.
This signal will turn on the second load switch and VOUT2 will
start to increase. The total startup time may vary according to
the difference between supply voltages that are used in the
application.
PGOOD pin requires an external pull up resistor that is
connected to the output voltage when there is no battery in the
load side and the logic level of the subsequent controller
permits. This would give logic levels similar to a CMOS output
stage for PGOOD, while still keeping the option to tie the pull-up
to a different supply voltage. A 100Kꢁ is recommended to be
used as pull up resistor. The PGOOD pin status is independent
of the ON pin position. This mean that PGOOD pin stays low
when the load switch is OFF. If the Power Good feature is not
used in the application the pin can be connected directly to
GND.
12
www.fairchildsemi.com
FPF2180/82/83/84/86/87 Rev. F
Dimensional Outline and Pad Layout
13
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FPF2180/82/83/84/86/87 Rev. F
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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 significant injury to the user.
2.
A critical component is any component of a life support
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Definition of Terms
Datasheet Identification
Product Status
Definition
This datasheet contains the design specifications for product development.
Specifications may change in any manner without notice.
Advance Information
Formative or In Design
This 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
This datasheet contains final specifications. Fairchild Semiconductor reserves
the right to make changes at any time without notice to improve design.
No Identification Needed
Obsolete
This datasheet contains specifications on a product that has been
discontinued by Fairchild semiconductor. The datasheet is printed for
reference information only.
Rev. I31
14
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FPF2180/82/83/84/86/87 Rev. F
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