LTC4360-1/LTC4360-2
Overvoltage Protection
Controller
FEATURES
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DESCRIPTION
The LTC
®
4360 overvoltage protection controller 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 LTC4360 controls an external N-channel MOSFET in
series with the input power supply. During overvoltage
transients, the LTC4360 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 LTC4360
provides protection from transients up to 80V without
requiring transient voltage suppressors or other external
components.
The LTC4360 has a delayed start-up and an adjustable dV/dt
ramp-up for inrush current limiting. A
PWRGD
pin provides
power good monitoring for V
IN
. Following an overvolt-
age condition, the LTC4360 automatically restarts with a
start-up delay. The LTC4360-1 features a soft shutdown
controlled by the
ON
pin, while the LTC4360-2 controls an
optional external P-channel MOSFET for negative voltage
protection.
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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
<1µs Overvoltage Turn-Off, Gentle Shutdown
Controls N-Channel MOSFET
Adjustable Power-Up dV/dt Limits Inrush
Reverse Voltage Protection (LTC4360-2)
Power Good Output
Low Current Shutdown (LTC4360-1)
Available in a Tiny 8-Lead SC70 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, How Swap and No R
SENSE
are trademarks of Linear Technology
Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Protection from Overvoltage
V
IN
5V
Si1470DH
C
OUT
GATE
IN
OUT
V
IN
, V
OUT
5V/DIV
V
OUT
V
OUT
5V
1.5A
Output Protected from Overvoltage at Input
V
IN
LTC4360-1
ON
PWRGD
GND
436012 TA01a
V
GATE
10V/DIV
Si1470DH
C
OUT
= 10µF
0.5µs/DIV
436012 TA01b
436012fa
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LTC4360-1/LTC4360-2
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Bias Supply Voltage (IN) ............................ –0.3V to 85V
Input Voltages
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
LTC4360C ................................................ 0°C to 70°C
LTC4360I .............................................–40°C to 85°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
PIN CONFIGURATION
LTC4360-1
IN 1
GND 2
GND 3
GND 4
TOP VIEW
8 GATE
7 OUT
6
ON
5
PWRGD
LTC4360-2
IN 1
GND 2
GND 3
GND 4
TOP VIEW
8 GATEP
7 GATE
6 OUT
5
PWRGD
SC8 PACKAGE
8-LEAD PLASTIC SC70
T
JMAX
= 125°C,
θ
JA
= 270°C/W
SC8 PACKAGE
8-LEAD PLASTIC SC70
T
JMAX
= 125°C,
θ
JA
= 270°C/W
ORDER INFORMATION
Lead Free Finish
TAPE AND REEL (MINI)
LTC4360CSC8-1#TRMPBF
LTC4360CSC8-2#TRMPBF
LTC4360ISC8-1#TRMPBF
LTC4360ISC8-2#TRMPBF
TAPE AND REEL
LTC4360CSC8-1#TRPBF
LTC4360CSC8-2#TRPBF
LTC4360ISC8-1#TRPBF
LTC4360ISC8-2#TRPBF
PART MARKING*
LDXN
LDXP
LDXN
LDXP
PACKAGE DESCRIPTION
8-Lead Plastic SC70
8-Lead Plastic SC70
8-Lead Plastic SC70
8-Lead Plastic SC70
TEMPERATURE RANGE
0°C to 70°C
0°C to 70°C
–40°C to 85°C
–40°C to 85°C
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/
436012fa
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LTC4360-1/LTC4360-2
ELECTRICAL CHARACTERISTICS
SYMBOL
Supplies
V
IN
V
IN(UVL)
I
IN
Thresholds
V
IN(OV)
∆V
OV
∆V
GATE
V
GATE(TH)
I
GATE(UP)
V
GATE(UP)
I
GATE(FST)
I
GATE(DN)
Input Pins
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
= Step 5V to 6.5V
V
GATE
> V
GATE(TH)
to
PWRGD
Low
V
ON
= Step 0V to 2.5V (LTC4360-1)
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 (LTC4360-1) unless otherwise noted.
PARAMETER
Input Voltage Range
Input Undervoltage Lockout
Input Supply Current
V
IN
Rising
LTC4360-1 V
ON
= 0V, LTC4360-2
LTC4360-1 V
ON
= 2.5V
IN Pin Overvoltage Threshold
Overvoltage Hysteresis
External N-Channel MOSFET Gate Drive
(V
GATE
– V
OUT
)
2.5V ≤ V
IN
< 3V, I
GATE
= –1µA
3V ≤ V
IN
< 5.5V, I
GATE
= –1µA
V
IN
Rising
CONDITIONS
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MIN
2.5
1.8
TYP
MAX
80
UNITS
V
V
µA
µA
V
mV
V
V
V
V
µA
V/ms
mA
µA
µA
µA
V
µA
V
MΩ
V
kΩ
ms
µs
µs
ms
µs
2.1
220
1.5
2.45
400
10
5.916
200
6
7.9
6.8
7.8
–15
4.5
60
80
20
±3
1.5
10
7.5
3.2
0.4
800
200
1
1
100
5
l
l
5.684
25
3.5
4.5
5.7
6.7
–5
1.5
15
10
5
0.4
2.5
5
0.8
250
50
5.8
100
4.5
6
6.3
7.2
–10
3
30
40
10
0
5
5.8
2
0.23
500
130
0.25
0.25
65
2
External Gate Drive
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GATE High Threshold for
PWRGD
Status V
IN
= 3.3V
V
IN
= 5V
GATE Pull-Up Current
GATE Ramp-Up
GATE Fast Pull-Down Current
GATE Pull-Down 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
GATE
= 1V
V
GATE
= 1V to 7V
Fast Turn-Off, V
IN
= 6V, V
GATE
= 9V
V
ON
= 2.5V, V
GATE
= 9V (LTC4360-1)
V
OUT
= 5V, V
ON
= 0V
V
OUT
= 5V, V
ON
= 2.5V
(LTC4360-1)
V
ON
= 2.5V (LTC4360-1)
V
IN
= 8V to 80V (LTC4360-2)
V
GATEP
= 3V (LTC4360-2)
V
IN
= 5V, I
PWRGD
= 3mA
V
IN
= 6.5V, V
PWRGD
= 1V
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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.
436012fa
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LTC4360-1/LTC4360-2
TYPICAL PERFORMANCE CHARACTERISTICS
T
A
= 25°C, V
IN
= 5V, V
ON
= 0V (LTC4360-1) unless otherwise noted.
Input Supply Current
vs Input Voltage
1000
LTC4360-1 V
ON
= 0V, LTC4360-2)
100
∆V
GATE
(V)
V
ON
= 2.5V
(LTC4360-1)
8
7
6
5
4
3
2
1
0.1
1
10
V
IN
(V)
100
436012 G01
GATE Drive vs GATE Current
40
GATE Fast Pull-Down Current
vs Temperature
V
IN
= 6V
V
GATE
= 9V
I
IN
(µA)
10
V
IN
= 3V
V
IN
= 2.5V
I
GATE(FST)
(mA)
V
IN
= 5V
35
30
1
25
0
0
2
4
6
8
I
GATE
(µA)
10
12
20
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
436012 G02
436012 G03
PWRGD
Voltage
vs
PWRGD
Current
500
8
7
400
V
PWRGD(OL)
(mV)
GATE Off Propagation Delay
vs Overdrive (V
OVDRV
)
V
IN
= STEP 5V TO (V
IN(OV)
+ V
OVDRV
)
12
11
V
GATE
/V
GATE(TH)
(V)
10
9
8
7
6
5
0
0.5
1
1.5
V
OVDRV
(V)
2
2.5
436012 G05
GATE Voltage and GATE High
Threshold (for
PWRGD
Status)
vs Input Voltage
V
IN
= V
OUT
V
GATE
6
t
OFF
(µs)
5
4
3
2
1
300
200
V
GATE(TH)
100
0
0
1
3
I
PWRGD
(mA)
2
4
5
436012 G04
0
4
2.5
3
3.5
4
4.5
V
IN
(V)
5
5.5
6
436012 G06
Normal Start-Up Sequence
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
LOAD = 10 , C
OUT
= 10µF
436012 G07
GATE Slow Ramp-Up
V
IN
5V/DIV
V
OUT
5V/DIV
V
GATE
10V/DIV
I
CABLE
0.5A/DIV
436012 G08
Entering Sleep Mode (LTC4360-1)
V
ON
5V/DIV
V
OUT
5V/DIV
V
GATE
10V/DIV
I
CABLE
0.5A/DIV
FIGURE 5 CIRCUIT
R
IN
= 150m , L
IN
= 0.7µH
LOAD = 10 , C
OUT
= 10µF
1ms/DIV
FIGURE 5 CIRCUIT
R
IN
= 150m , L
IN
= 0.7µH
LOAD = 10 , C
OUT
= 10µF
50µs/DIV
436012 G09
436012fa
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LTC4360-1/LTC4360-2
PIN FUNCTIONS
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 (LTC4360-2):
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. Dur-
ing lockout, GATE is held low and the
PWRGD
pull-down
releases.
ON
(LTC4360-1):
On Control Input. A logic low at
ON
enables the LTC4360-1. A logic high at
ON
activates a
low current pull-down at the GATE pin and causes the
LTC4360-1 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)
.
BLOCK DIAGRAM
GATEP
(LTC4360-2)
200k
5.8V
IN
1.8M
CHARGE
PUMP
10µA
GATE
GATE HIGH
COMPARATOR
ON
(LTC4360-1)
1V
5µA
5.8V
OUT
V
GATE(TH)
+
–
+
–
CONTROL
OVERVOLTAGE
COMPARATOR
+
–
5.8V
5.7V
PWRGD
500k
GND
436012 BD
436012fa
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