LTC4361-1/LTC4361-2
Overvoltage/Overcurrent
Protection Controller
FEATURES
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DESCRIPTION
The
LTC
®
4361
overvoltage/overcurrent protection con-
troller safeguards 2.5V to 5.5V systems from input sup-
ply overvoltage. It is designed for portable devices with
multiple power supply options including wall adaptors,
car battery adaptors and USB ports.
The LTC4361 controls an external N-channel MOSFET
in series with the input power supply. During overvolt-
age transients, the LTC4361 turns off the MOSFET within
1µs, isolating downstream components from the input
supply. Inductive cable transients are absorbed by the
MOSFET and load capacitance. In most applications, the
LTC4361 provides protection from transients up to 80V
without requiring transient voltage suppressors or other
external components.
The LTC4361 has a delayed start-up and adjustable dV/
dt ramp-up for inrush current limiting. A
PWRGD
pin
provides power good monitoring for V
IN
. The LTC4361
features a soft shutdown controlled by the
ON
pin and
drives an optional external P-channel MOSFET for nega-
tive voltage protection. Following an overvoltage condi-
tion, the LTC4361 automatically restarts with a start-up
delay. After an overcurrent fault, the LTC4361-1 remains
off while the LTC4361-2 automatically restarts after a
130ms start-up delay.
All registered trademarks and trademarks are the property of their respective owners.
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2.5V to 5.5V Operation
Overvoltage Protection Up to 80V
No Input Capacitor or TVS Required for Most
Applications
2% Accurate 5.8V Overvoltage Threshold
10% Accurate 50mV Overcurrent Circuit Breaker
<1µs Overvoltage Turn-Off, Gentle Shutdown
Controls N-Channel MOSFET
Adjustable Power-Up dV/dt Limits Inrush Current
Reverse Voltage Protection
Power Good Output
Low Current Shutdown
Latchoff (LTC4361-1) or Auto-Retry (LTC4361-2)
After Overcurrent
Available in 8-Lead ThinSOT™ and 8-Lead
(2mm
×
2mm) DFN Packages
APPLICATIONS
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USB Protection
Handheld Computers
Cell/Smart Phones
MP3/MP4 Players
Digital Cameras
TYPICAL APPLICATION
Protection from Overvoltage and Overcurrent
V
IN
5V
0.025Ω
Si1470DH
C
OUT
GATE
SENSE OUT
IN
LTC4361
ON
PWRGD
GND
436112 TA01a
Output Protected from Overvoltage at Input
V
IN
V
OUT
5V
1.5A
V
IN
, V
OUT
5V/DIV
V
GATE
10V/DIV
V
OUT
Si1470DH
C
OUT
= 10µF
0.5µs/DIV
436112 TA01b
Document Feedback
For more information
www.analog.com
1
Rev C
LTC4361-1/LTC4361-2
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Bias Supply Voltage (IN) ............................ –0.3V to 85V
Input Voltages
SENSE ................................................... –0.3V to 85V
OUT,
ON
................................................... –0.3V to 9V
Output Voltages
PWRGD
.................................................... –0.3V to 9V
GATE (Note 3) ........................................ –0.3V to 15V
GATEP.................................................... –0.3V to 85V
IN to GATEP ........................................... –0.3V to 10V
Operating Temperature Range
LTC4361C ................................................ 0°C to 70°C
LTC4361I .............................................–40°C to 85°C
LTC4361H .......................................... –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
TSOT................................................................. 300°C
PIN CONFIGURATION
TOP VIEW
ON
1
OUT 2
GATEP 3
GND 4
8
PWRGD
7 GATE
6 SENSE
5 IN
GND 1
GATEP 2
OUT 3
ON
4
9
TOP VIEW
8 IN
7 SENSE
6 GATE
5
PWRGD
TS8 PACKAGE
8-LEAD PLASTIC TSOT-23
T
JMAX
= 125°C,
θ
JA
= 195°C/W
DC PACKAGE
8-LEAD (2mm
×
2mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 102°C/W
EXPOSED PAD (PIN 9) IS GND, CONNECTION OPTIONAL
ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI)
LTC4361CTS8-1#TRMPBF
LTC4361CTS8-2#TRMPBF
LTC4361ITS8-1#TRMPBF
LTC4361ITS8-2#TRMPBF
LTC4361HTS8-1#TRMPBF
LTC4361HTS8-2#TRMPBF
LTC4361CDC-1#TRMPBF
LTC4361CDC-2#TRMPBF
LTC4361IDC-1#TRMPBF
LTC4361IDC-2#TRMPBF
LTC4361HDC-1#TRMPBF
LTC4361HDC-2#TRMPBF
TAPE AND REEL
LTC4361CTS8-1#TRPBF
LTC4361CTS8-2#TRPBF
LTC4361ITS8-1#TRPBF
LTC4361ITS8-2#TRPBF
LTC4361HTS8-1#TRPBF
LTC4361HTS8-2#TRPBF
LTC4361CDC-1#TRPBF
LTC4361CDC-2#TRPBF
LTC4361IDC-1#TRPBF
LTC4361IDC-2#TRPBF
LTC4361HDC-1#TRPBF
LTC4361HDC-2#TRPBF
PART MARKING*
LTDWN
LTFMN
LTDWN
LTFMN
LTDWN
LTFMN
LDWP
LFMP
LDWP
LFMP
LDWP
LFMP
PACKAGE DESCRIPTION
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead Plastic TSOT-23
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
8-Lead (2mm
×
2mm) Plastic DFN
TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container.
Consult ADI Marketing for parts specified with wider operating temperature ranges.
Consult ADI Marketing for information on lead based finish parts.
Tape and reel specifications.
Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix.
2
Rev C
For more information
www.analog.com
LTC4361-1/LTC4361-2
ELECTRICAL CHARACTERISTICS
SYMBOL
Supplies
V
IN
V
IN(UVL)
I
IN
Thresholds
V
IN(OV)
V
IN(OVL)
∆V
OV
∆V
OC
∆V
GATE
V
GATE(TH)
I
GATE(UP)
V
GATE(UP)
I
GATE(FST)
I
GATE(DN)
Input Pins
I
SENSE(IN)
I
OUT(IN)
V
ON(TH)
I
ON
Output Pins
V
GATEP(CLP)
R
GATEP
V
PWRGD(OL)
R
PWRGD
Delay
t
ON
t
OFF
t
PWRGD
t
ON(OFF)
GATE On Delay
GATE Off Propagation Delay
PWRGD
Delay
ON
High to GATE Off
V
IN
High to I
GATE
= –5µA
V
IN
= Step 5V to 6.5V to
PWRGD
High
V
IN
– V
SENSE
= Step 0mV to 100mV
V
IN
= Step 5V to 6.5V
V
GATE
> V
GATE(TH)
to
PWRGD
Low
V
ON
= Step 0V to 2.5V
l
l
l
l
l
l
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
IN Pin Overvoltage Threshold
IN Pin Overvoltage Recovery Threshold
Overvoltage Hysteresis
Overcurrent Threshold
External N-Channel MOSFET Gate Drive
(V
GATE
– V
OUT
)
V
IN
– V
SENSE
2.5V ≤ V
IN
< 3V, I
GATE
= –1µA
3V ≤ V
IN
< 5.5V, I
GATE
= –1µA
V
IN
Rising
V
IN
Falling
CONDITIONS
l
l
l
l
MIN
2.5
1.8
TYP
MAX
80
UNITS
V
V
µA
µA
V
V
mV
mV
V
V
V
V
µA
V/ms
mA
mA
µA
nA
2.1
220
1.5
2.47
400
10
5.916
5.85
300
55
6
7.9
6.8
7.8
–15
4.5
60
60
80
l
l
l
l
5.684
5.51
25
45
3.5
4.5
5.7
6.7
–4.5
1.3
15
12
5
5.8
5.7
100
50
4.5
6
6.3
7.2
–10
3
30
30
40
10
External Gate Drive
l
l
l
l
l
l
l
l
l
GATE High Threshold for
PWRGD
Status V
IN
= 3.3V
V
IN
= 5V
GATE Pull-Up Current
GATE Ramp-Up
GATE Pull-Down Current
GATE Pull-Down Current
SENSE Input Current
OUT Input Current
ON
Input Threshold
ON
Pull-Down Current
IN to GATEP Clamp Voltage
GATEP Resistive Pull-Down
PWRGD
Output Low Voltage
PWRGD
Pull-Up Resistance to OUT
V
ON
= 2.5V
V
IN
= 8V to 80V
V
GATEP
= 3V
V
IN
= 5V, I
PWRGD
= 3mA
V
IN
= 6.5V, V
PWRGD
= 1V
(C-, I-Grade)
(H-Grade)
V
GATE
= 1V
V
GATE
= 1V to 7V
Fast Turn-Off, V
IN
= 6V, V
GATE
= 9V (C-, I-Grade)
(H-Grade)
V
ON
= 2.5V, V
GATE
= 9V
V
SENSE
= 5V
V
OUT
= 5V, V
ON
= 0V
V
OUT
= 5V, V
ON
= 2.5V
l
l
l
l
5
0.4
2
5
0.6
10
0
5
5.8
2
0.23
0.23
20
±3
1.5
10
7.9
3.2
0.4
0.5
800
219
1
20
1
105
5
µA
µA
V
µA
V
MΩ
V
V
kΩ
ms
µs
µs
µs
ms
µs
l
l
l
l
l
220
50
5
25
500
130
0.25
10
0.25
65
2
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:
An internal clamp limits V
GATE
to a minimum of 4.5V above V
OUT
.
Driving this pin to voltages beyond this clamp may damage the device.
For more information
www.analog.com
3
Rev C
LTC4361-1/LTC4361-2
TYPICAL PERFORMANCE CHARACTERISTICS
T
A
= 25°C, V
IN
= 5V, V
ON
= 0V, unless otherwise noted.
Input Supply Current
vs Input Voltage
10000
1000
V
ON
= 0V
∆V
GATE
(V)
I
IN
(µA)
100
V
ON
= 2.5V
8
7
6
5
4
3
2
1
0.1
1
10
V
IN
(V)
100
436112 G01
GATE Drive vs GATE Current
40
GATE Fast Pull-Down Current
vs Temperature
V
IN
= 6V
V
GATE
= 9V
V
IN
= 3V
I
GATE(FST)
(mA)
V
IN
= 5V
35
30
10
1
V
IN
= 2.5V
25
0
0
2
4
6
I
GATE
(µA)
8
10
12
20
–50
–25
50
75
0
25
TEMPERATURE (°C)
100
125
436112 G03
436112 G02
PWRGD
Voltage
vs
PWRGD
Current
500
8
7
400
V
PWRGD(OL)
(mV)
GATE Off Propagation Delay
vs Overdrive
V
IN
= STEP 5V TO (V
IN(OV)
+ V
OVDRV
)
12
11
V
GATE
/VG
GATE(TH)
(V)
10
9
8
7
6
5
0
0.5
1
1.5
V
OVDRV
(V)
2
2.5
436112 G05
GATE Voltage and GATE High
Threshold (for
PWRGD
Status)
vs Input Voltage
V
IN
= V
OUT
V
GATE
6
5
t
OFF
(µs)
4
3
2
1
300
200
V
GATE(TH)
100
0
0
1
3
I
PWRGD
(mA)
2
4
5
436112 G04
0
4
2.5
3
3.5
4
4.5
V
IN
(V)
5
5.5
6
436112 G06
Normal Start-Up Sequence
V
IN
5V/DIV
V
OUT
5V/DIV
V
GATE
10V/DIV
V
IN
5V/DIV
V
OUT
5V/DIV
V
GATE
10V/DIV
I
CABLE
0.5A/DIV
20ms/DIV
FIGURE 5 CIRCUIT
R
IN
= 150m , L
IN
= 0.7µH
R
SENSE
= 25m
LOAD = 10 , C
OUT
= 10µF
436112 G07
GATE Slow Ramp-Up
V
ON
5V/DIV
V
OUT
5V/DIV
V
GATE
10V/DIV
I
CABLE
0.5A/DIV
1ms/DIV
FIGURE 5 CIRCUIT
R
IN
= 150m , L
IN
= 0.7µH
R
SENSE
= 25m
LOAD = 10 , C
OUT
= 10µF
436112 G08
Entering Sleep Mode
I
CABLE
0.5A/DIV
FIGURE 5 CIRCUIT
R
IN
= 150m , L
IN
= 0.7µH
R
SENSE
= 25m
LOAD = 10 , C
OUT
= 10µF
50µs/DIV
436112 G09
4
Rev C
For more information
www.analog.com
LTC4361-1/LTC4361-2
PIN FUNCTIONS
Exposed Pad (DFN):
Ground. Connection to PCB is
optional.
GATE:
Gate Drive for External N-Channel MOSFET. An
internal charge pump provides a 10µA pull-up current
to charge the gate of the external N-channel MOSFET. An
additional ramp circuit limits the GATE ramp rate when
turning on to 3V/ms. For slower ramp rates, connect an
external capacitor from GATE to GND. An internal clamp
limits GATE to 6V above the OUT pin voltage. An internal
GATE high comparator controls the
PWRGD
pin.
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. This
pin is internally clamped to 5.8V below V
IN
. An internal
2M resistor connects this pin to ground. Connect to IN
if not used.
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)
–
∆V
OV
to release the overvoltage lockout. During
lockout, GATE is held low and the
PWRGD
pull-down
releases.
ON:
On Control Input. A logic low at
ON
enables the
LTC4361. A logic high at
ON
activates a low current pull-
down at the GATE pin and causes the LTC4361 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:
Output Voltage Sense Input for GATE Clamp. Connect
to the source of the external N-channel MOSFET to sense
the output voltage for GATE to OUT clamp.
PWRGD:
Power Good Status. Open-drain output with
internal 500k resistive pull-up to OUT. Pulls low 65ms
after GATE ramps above V
GATE(TH)
.
SENSE:
Current Sense Input. Connect a sense resistor
between IN and SENSE. An overcurrent protection circuit
turns off the N-channel MOSFET when the voltage across
the sense resistor exceeds 50mV for more than 10µs.
For more information
www.analog.com
5
Rev C
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