LTC4362-1/LTC4362-2
1.2A Overvoltage/
Overcurrent Protector
FEATURES
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DESCRIPTION
The LTC
®
4362 monolithic overvoltage/overcurrent protec-
tor safeguards 2.5V to 5.5V systems from power supply
overvoltage. It is designed for portable devices with multiple
power supply options including wall adaptors, car battery
adaptors and USB ports.
The LTC4362 controls an internal 40mΩ N-channel MOSFET
in series with the input power supply. During overvoltage
transients, the LTC4362 turns off the MOSFET within 1μs,
isolating downstream components from the input supply.
In most applications, the LTC4362 rides through induc-
tive cable transients without requiring transient voltage
suppressors or other external components. An internal
current sense resistor is used to implement overcurrent
protection.
The LTC4362 has a delayed start-up at plug-in and con-
trolled dV/dt ramp-up for inrush current limiting. A
PWRGD
pin provides power good monitoring for V
IN
. The LTC4362
features a soft-shutdown controlled by the
ON
pin and
drives an optional external P-channel MOSFET for negative
voltage protection. Following an overvoltage condition, the
LTC4362 automatically restarts with a 130ms delay. After
an overcurrent fault, the LTC4362-1 remains off while the
LTC4362-2 automatically restarts after a 130ms delay.
2.5V to 5.5V Operation
Overvoltage Protection Up to 28V
Internal 40mΩ N-Channel MOSFET and 31mΩ R
SENSE
Avalanche Rated MOSFET Requires No Input
Capacitor or TVS for Most Applications
<1μs
Overvoltage Turn-Off, Gentle Shutdown
2% Accurate 5.8V Overvoltage Threshold
20% Accurate 1.5A Overcurrent Threshold
Input Withstands Up to ±25kV HBM ESD with 1μF C
OUT
Controlled Power-Up dV/dt Limits Inrush Current
Reverse Voltage Protection Driver
Low Current Shutdown
Latchoff (LTC4362-1) or Auto-Retry (LTC4362-2)
After Overcurrent
Available in 8-Lead DFN 2mm
×
3mm Package
APPLICATIONS
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USB Protection
Handheld Computers
Cell/Smart Phones
MP3/MP4 Players
Digital Cameras
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
ThinSOT, PowerPath and Hot Swap are trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
TYPICAL APPLICATION
Protection from Overvoltage and Overcurrent
V
IN
5V
V
OUT
5V
0.5A
Output Protected from Overvoltage at Input
V
IN
IN
OUT
LTC4362
C
OUT
ON
PWRGD
GND
436212 TA01a
V
OUT
V
IN
, V
OUT
5V/DIV
0.2μs/DIV
C
OUT
= 10μF
436212 TA01b
436212f
1
LTC4362-1/LTC4362-2
ABSOLUTE MAXIMUM RATINGS
(Notes 1 and 2)
PIN CONFIGURATION
TOP VIEW
GATEP 1
IN 2
GND 3
SENSE 4
9
SENSE
8 OUT
7 OUT
6
ON
5
PWRGD
Bias Supply Voltage
IN to OUT (Note 3) ................................. –0.3V to 28V
Input Voltages
SENSE to OUT (Notes 3 and 4) .............. –0.3V to 28V
ON
........................................................... –0.3V to 9V
Output Voltages
OUT,
PWRGD
........................................... –0.3V to 9V
IN to GATEP ........................................... –0.3V to 10V
Operating Temperature Range
LTC4362C ................................................ 0°C to 70°C
LTC4362I .............................................–40°C to 85°C
Storage Temperature Range ................. –65°C to 150°C
DCB PACKAGE
8-LEAD (2mm 3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 64°C/W
ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI)
TAPE AND REEL
PART MARKING*
LFNC
LFJN
LFNC
PACKAGE DESCRIPTION
8-Lead Plastic DFN
8-Lead Plastic DFN
8-Lead Plastic DFN
TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
LTC4362CDCB-1#TRMPBF LTC4362CDCB-1#TRPBF
LTC4362CDCB-2#TRMPBF LTC4362CDCB-2#TRPBF
LTC4362IDCB-1#TRMPBF
LTC4362IDCB-1#TRPBF
LTC4362IDCB-2#TRMPBF LTC4362IDCB-2#TRPBF
LFJN
8-Lead Plastic DFN
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
436212f
2
LTC4362-1/LTC4362-2
ELECTRICAL CHARACTERISTICS
SYMBOL
Supplies
V
IN
V
IN(UVL)
I
IN
Thresholds
V
IN(OV)
ΔV
OV
Input Pins
V
ON(TH)
I
ON
Output Pins
V
OUT(UP)
I
OUT
V
GATEP(CLP)
R
GATEP
V
PWRGD(OL)
R
PWRGD
R
ON
I
TRIP
I
AS
E
AS
Delay
t
ON
t
OFF(OV)
t
OFF(OC)
t
PWRGD(LH)
t
PWRGD(HL)
t
ON(OFF)
ESD Protection
ESD Protection for IN to GND
C
OUT
= 1μF Human Body Model
,
±25
kV
Turn-On Delay
Turn-Off Delay for Overvoltage
Turn-Off Delay for Overcurrent
PWRGD
Rising Delay
PWRGD
Falling Delay
ON
High to N-channel MOSFET Off
V
IN
High to V
OUT
= 0.5V, R
OUT
= 1kΩ
V
IN
= 5V
I
OUT
= 0.5A
V
IN
= 5V
6.5V to V
OUT
= 4.5V, R
OUT
= 1kΩ
3A to V
OUT
= 4.5V
6.5V
l
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The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 5V, V
ON
= 0V unless otherwise noted.
PARAMETER
Input Voltage Range
Input Undervoltage Lockout
Input Supply Current
V
IN
Rising
V
ON
= 0V
V
ON
= 2.5V
V
IN
Rising
CONDITIONS
l
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l
l
l
l
l
MIN
2.5
1.8
TYP
MAX
28
UNITS
V
V
μA
μA
V
mV
V
μA
V/ms
μA
V
MΩ
V
kΩ
mΩ
A
A
mJ
2.1
220
1.5
2.45
400
10
5.916
200
1.5
IN Pin Overvoltage Threshold
Overvoltage Hysteresis
ON
Input Threshold
ON
Pull-Down Current
OUT Turn-On Ramp-Rate
OUT Leakage Current
IN to GATEP Clamp Voltage
GATEP Pull-Down Resistance
PWRGD
Output Low Voltage
PWRGD
Pull-Up Resistance to OUT
On Resistance
Overcurrent Threshold
Peak Avalanche Current
Single Pulse Avalanche Energy
5.684
25
0.4
2.5
1.5
5
0.8
250
5.8
100
V
ON
= 2.5V
V
OUT
= 0.5V to 4V
V
ON
= 2.5V, V
OUT
= 5V
V
GATEP
= 3V
V
IN
= 5V, I
PWRGD
= 3mA
V
IN
= 6.5V, V
PWRGD
= 1V
I
OUT
= 0.5A
L = 0.1mH (Note 5)
I
AS
= 10A, L = 0.1mH (Note 5)
l
5
3
0
5.8
2
0.23
500
40
10
4.5
±3
7.5
3.2
0.4
800
70
1.8
l
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l
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l
l
l
Internal N-Channel MOSFET
1.2
1.5
10
10
50
5
130
0.45
10
0.3
25
65
40
200
1
20
1
100
100
ms
μs
μs
μs
ms
μs
V
IN
= 0V 5V, V
OUT
= 0.5V to
PWRGD
Pull Low,
R
OUT
= 1kΩ
V
ON
= 0V
2.5V
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
All currents into device pins are positive; all currents out of device
pins are negative. All voltages are referenced to GND unless otherwise
specified.
Note 3:
The minimum drain-source breakdown voltage of the internal
MOSFET is 28V. Driving the IN and SENSE pins more than 28V above OUT
may damage the device if the E
AS
capability of the MOSFET is exceeded.
Note 4:
An internal current sense resistor ties IN and SENSE. Driving
SENSE relative to IN may damage the resistor.
Note 5:
The I
AS
and E
AS
typical values are based on characterization and
are not production tested.
436212f
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LTC4362-1/LTC4362-2
TYPICAL PERFORMANCE CHARACTERISTICS
Specifications are at T
A
= 25°C, V
IN
= 5V, V
ON
= 0V unless otherwise noted.
Input Supply Current
vs Input Voltage
1000
V
ON
= 0V
100
V
ON
= 2.5V
10
V
IN(0V)
(V)
I
IN
(μA)
5.80
400
5.82
V
PWRGD(OL)
(mV)
300
5.84
Overvoltage Threshold
vs Temperature
500
PWRGD
Voltage vs
PWRGD
Current
200
1
5.78
100
0.1
1
10
V
IN
(V)
100
436212 G01
5.76
–50
0
–25
0
25
50
TEMPERATURE (°C)
75
100
0
1
2
3
I
PWRGD
(mA)
4
5
436212 G03
436212 G02
Internal MOSFET On Resistance
vs Temperature
60
40
Internal R
SENSE
vs Temperature
1.60
Overcurrent Threshold
vs Temperature
INTERNAL R
SENSE
(mΩ)
50
R
ON
(mΩ)
V
IN
= 3V
40
V
IN
= 5V
35
I
TRIP
(A)
–25
0
25
50
TEMPERATURE (°C)
75
100
1.55
30
1.50
30
25
1.45
20
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
20
–50
1.40
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
436212 G04
436212 G05
436212 G06
Overvoltage Turn-Off Delay
vs Temperature
1.0
V
IN
= STEP 5V TO 6.5V
14
Overcurrent Turn-Off Delay
vs Temperature
I
OUT
= STEP 0.5A TO 3A
8
Overvoltage Turn-Off Delay
vs Overdrive (V
OVDRV
)
V
IN
= STEP 5V TO (V
IN(OV)
+ V
OVDRV
)
0.8
12
t
OFF(OC)
(μs)
t
OFF(OV)
(μs)
–25
0
25
50
TEMPERATURE (°C)
75
100
6
t
OFF(OV)
(μs)
0.6
10
4
0.4
0.2
8
2
0
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
6
–50
0
0
0.5
1
1.5
V
OVDRV
(V)
2
2.5
436212 G09
436212 G07
436212 G08
436212f
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LTC4362-1/LTC4362-2
TYPICAL PERFORMANCE CHARACTERISTICS
Specifications are at T
A
= 25°C, V
IN
= 5V, V
ON
= 0V unless otherwise noted.
Normal Start-Up Sequence
V
IN
5V/DIV
Turn-On Ramp-Up
V
IN
5V/DIV
V
OUT
5V/DIV
Entering Sleep Mode
V
IN
5V/DIV
V
OUT
5V/DIV
V
OUT
5V/DIV
V
ON
5V/DIV
I
CABLE
0.5A/DIV
I
CABLE
0.5A/DIV
I
CABLE
0.5A/DIV
20ms/DIV
FIGURE 4 CIRCUIT
R
IN
= 150mΩ, L
IN
= 0.7μH
LOAD = 10Ω, C
OUT
= 10μF
436212 G10
1ms/DIV
FIGURE 4 CIRCUIT
R
IN
= 150mΩ, L
IN
= 0.7μH
LOAD = 10Ω, C
OUT
= 10μF
436212 G11
50μs/DIV
FIGURE 4 CIRCUIT
R
IN
= 150mΩ, L
IN
= 0.7μH
LOAD = 10Ω, C
OUT
= 10μF
436212 G12
PIN FUNCTIONS
GATEP:
Gate Drive for External P-channel MOSFET. GATEP
connects to the gate of an optional external P-channel
MOSFET to protect against negative voltages at IN. Inter-
nally clamped to 5.8V below V
IN
. An internal 2M resistor
connects this pin to ground. Connect to IN if unused.
GND:
Device Ground.
IN:
Supply Voltage Input. Connect this pin to the input
power supply. This pin has an overvoltage threshold of
5.8V. After an overvoltage event, this pin must fall below
V
IN(OV)
–
ΔV
OV
to release the overvoltage lockout. During
lockout, the internal N-channel MOSFET remains off and
the
PWRGD
pull-down releases.
ON:
On Control Input. A logic low at
ON
enables the
LTC4362. A logic high at
ON
activates a low current pull-
down on the gate of the internal N-channel MOSFET and
causes the LTC4362 to enter a low current sleep mode. An
internal 5μA current pulls
ON
down to ground. Connect
to ground or leave open if unused.
OUT:
Source of Internal N-Channel MOSFET. Connect to
load.
PWRGD:
Power Good Status. Open-drain output with
internal 500k resistive pull-up to OUT. Pulls low 65ms
after the MOSFET gate ramps above its internal gate high
threshold.
SENSE, Exposed Pad:
Current Sense Node and Internal
N-Channel MOSFET Drain. An internal sense resistor
between IN and SENSE is used to implement the 1.5A
overcurrent threshold. The exposed pad is connected to
SENSE and must be soldered to an electrically isolated
printed circuit board trace to properly transfer the heat
out of the package. To disable the overcurrent function,
connect SENSE and the exposed pad to IN.
436212f
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