LT4356MP-1/LT4356MP-2
Surge Stopper
FEATURES
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DESCRIPTION
The LT
®
4356 surge stopper protects loads from high voltage
transients. It regulates the output during an overvoltage
event, such as load dump in automobiles, by controlling
the gate of an external N-channel MOSFET. The output
is limited to a safe value thereby allowing the loads to
continue functioning. The LT4356MP also monitors the
voltage drop between the V
CC
and SNS pins to protect
against overcurrent faults. An internal amplifier limits the
current sense voltage to 50mV. In either fault condition, a
timer is started inversely proportional to MOSFET stress.
If the timer expires, the
FLT
pin pulls low to warn of an
impending power-down. If the condition persists, the
MOSFET is turned off. After a cooldown period, the GATE
pin pulls up turning on the MOSFET again.
The spare amplifier may be used as a voltage detection
comparator or as a linear regulator controller driving an
external PNP pass transistor.
Back-to-back FETs can be used in lieu of a Schottky diode
for reverse input protection, reducing voltage drop and
power loss. A shutdown pin reduces the quiescent current
to less than 7μA during shutdown for the LT4356-1 and
60μA for the LT4356-2 while keeping the reference and
auxiliary amplifier functioning.
Stops High Voltage Surges
Adjustable Output Clamp Voltage
Overcurrent Protection
Wide Operation Range: 4V to 80V
Reverse Input Protection to –60V
Low 7μA Shutdown Current, LT4356-1
Adjustable Fault Timer
Controls N-channel MOSFET
Shutdown Pin Withstands –60V to 100V
Fault Output Indication
Guaranteed Operation –55°C to 125°C
Spare Amplifier for Level Detection Comparator or
Linear Regulator Controller
Available in 10-Pin MSOP or 16-Pin SO Packages
APPLICATIONS
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Automotive/Avionic Surge Protection
Hot Swap/Live Insertion
High Side Switch for Battery Powered Systems
Intrinsic Safety Applications
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
4A, 12V Overvoltage Output Regulator
V
IN
12V
10mΩ
IRLR2908
V
OUT
80V INPUT SURGE
10Ω
383k
V
CC
SHDN
IN
+
100k
EN
UNDERVOLTAGE
A
OUT
GND
TMR
FLT
4356mp12 TA01
Overvoltage Protector Regulates Output at
27V During Transient
C
TMR
= 6.8μF
I
LOAD
= 500mA
102k
OUT
FB
4.99k
V
CC
DC-DC
CONVERTER
SHDN
GND
FAULT
V
OUT
20V/DIV
12V
4356mp12 TA01b
SNS
GATE
V
IN
20V/DIV
12V
27V ADJUSTABLE CLAMP
LT4356S
100ms/DIV
0.1μF
4356mp12f
1
LT4356MP-1/LT4356MP-2
ABSOLUTE MAXIMUM RATINGS
(Notes 1 and 2)
V
CC
,
SHDN
................................................ –60V to 100V
SNS............................. V
CC
– 30V or –60V to V
CC
+ 0.3V
OUT, A
OUT
,
FLT,
EN ..................................... –0.3V to 80V
GATE (Note 3) .................................–0.3V to V
OUT
+ 10V
FB, TMR, IN
+
................................................ –0.3V to 6V
A
OUT
, EN,
FLT,
IN
+
..................................................–3mA
Operating Temperature Range
LT4356M ............................................ –55°C to 125°C
Storage Temperature Range
MS, SO .............................................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
MS, SO ............................................................. 300°C
PIN CONFIGURATION
TOP VIEW
TMR 1
TOP VIEW
FB
OUT
GATE
SNS
V
CC
1
2
3
4
5
10
9
8
7
6
TMR
GND
EN
FLT
SHDN
FB 2
NC 3
OUT 4
GATE 5
NC 6
SNS 7
V
CC
8
16 IN
+
15 NC
14 A
OUT
13 NC
12 GND
11 EN
10
FLT
9
SHDN
MS PACKAGE
10-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 160°C/W
S PACKAGE
16-LEAD PLASTIC SO
T
JMAX
= 150°C,
θ
JA
= 100°C/W
ORDER INFORMATION
LEAD FREE FINISH
LT4356MPMS-1#PBF
LT4356MPS-1#PBF
LT4356MPS-2#PBF
LEAD BASED FINISH
LT4356MPMS-1
LT4356MPS-1
LT4356MPS-2
TAPE AND REEL
LT4356MPMS-1#TRPBF
LT4356MPS-1#TRPBF
LT4356MPS-2#TRPBF
TAPE AND REEL
LT4356MPMS-1#TR
LT4356MPS-1#TR
LT4356MPS-2#TR
PART MARKING
LTFGD
LT4356MPS-1
LT4356MPS-2
PART MARKING
LTFGD
LT4356MPS-1
LT4356MPS-2
PACKAGE DESCRIPTION
10-Lead Plastic MSOP
16-Lead Plastic SO
16-Lead Plastic SO
PACKAGE DESCRIPTION
10-Lead Plastic MSOP
16-Lead Plastic SO
16-Lead Plastic SO
TEMPERATURE RANGE
–55°C to 125°C
–55°C to 125°C
–55°C to 125°C
TEMPERATURE RANGE
–55°C to 125°C
–55°C to 125°C
–55°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
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/
4356mp12f
2
LT4356MP-1/LT4356MP-2
ELECTRICAL CHARACTERISTICS
SYMBOL
V
CC
I
CC
PARAMETER
Operating Voltage Range
V
CC
Supply Current
CONDITIONS
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 12V unless otherwise noted.
MIN
4
1
7
7
60
60
0.3
0.8
4.5
10
–4
–4.5
75
5
1.5
1.215
42.5
43
5
l
l
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l
l
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l
l
l
l
l
l
l
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l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
l
TYP
MAX
80
1.5
25
40
70
250
1
2
8
16
–36
–50
UNITS
V
mA
μA
μA
μA
μA
mA
mA
V
V
μA
μA
mA
mA
mA
V
μA
mV
mV
μA
μA
μA
μA
μA
μA
μA
μA
μA
V
V
mV
V
μA
V
mV
μA
mA
V
V
V
V
μA
μs
μs
I
R
ΔV
GATE
I
GATE(UP)
I
GATE(DN)
Reverse Input Current
GATE Pin Output High Voltage
GATE Pin Pull-Up Current
GATE Pin Pull-Down Current
V
FB
I
FB
ΔV
SNS
I
SNS
I
LEAK
I
TMR
FB Pin Servo Voltage
FB Pin Input Current
Overcurrent Fault Threshold
SNS Pin Input Current
FLT,
EN Pins Leakage Current
A
OUT
Pin Leakage Current
TMR Pin Pull-Up Current
V
SHDN
= Float
V
SHDN
= 0V, IN
+
= 1.3V, LT4356MP-1
LT4356MP-1
V
SHDN
= 0V, IN
+
= 1.3V, LT4356MP-2
LT4356MP-2
V
SNS
= V
CC
= –30V,
SHDN
Open
V
SNS
= V
CC
= V
SHDN
= –30V
V
CC
= 4V; (V
GATE
– V
OUT
)
80V ≥ V
CC
≥ 8V; (V
GATE
– V
OUT
)
V
GATE
= 12V; V
CC
= 12V
V
GATE
= 48V; V
CC
= 48V
Overvoltage, V
FB
= 1.4V, V
GATE
= 12V
Overcurrent, V
CC
– V
SNS
= 120mV, V
GATE
= 12V
Shutdown Mode, V
SHDN
= 0V, V
GATE
= 12V
V
GATE
= 12V; V
OUT
= 12V
V
FB
= 1.25V
ΔV
SNS
= (V
CC
– V
SNS
), V
CC
= 12V
ΔV
SNS
= (V
CC
– V
SNS
), V
CC
= 48V
V
SNS
= V
CC
= 12V to 48V
FLT,
EN = 80V
A
OUT
= 80V
V
TMR
= 1V, V
FB
= 1.5V, (V
CC
– V
OUT
) = 0.5V
V
TMR
= 1V, V
FB
= 1.5V, (V
CC
– V
OUT
) = 75V
V
TMR
= 1.3V, V
FB
= 1.5V
V
TMR
= 1V,
ΔV
SNS
= 60mV, (V
CC
– V
OUT
) = 0.5V
V
TMR
= 1V,
ΔV
SNS
= 60mV, (V
CC
– V
OUT
) = 80V
V
TMR
= 1V, V
FB
= 1V,
ΔV
SNS
= 0V
FLT
From High to Low, V
CC
= 5V to 80V
V
GATE
From Low to High, V
CC
= 5V to 80V
From
FLT
Going Low to GATE Going Low, V
CC
= 5V to 80V
V
IN+
= 1.25V
I
SINK
= 2mA
I
SINK
= 0.1mA
V
OUT
= V
CC
= 12V
V
OUT
= V
CC
= 12V, V
SHDN
= 0V
ΔV
OUT
= V
CC
– V
OUT
; EN from Low to High
V
CC
= 12V to 48V
V
CC
= 12V to 48V
V
SHDN
= 0V
GATE from High to Low,
ΔV
SNS
= 0
→
120mV
GATE from High to Low, V
FB
= 0
→
1.5V
–23
–30
150
10
5
1.25
0.3
50
51
10
1.275
1
55
56
22
2.5
4.5
–4
–56
–8.5
–6.5
–315
2.7
1.28
0.52
120
1.28
1
8
800
300
14
0.7
1.7
2.1
2
–8
4
1
TMR Pin Pull-Down Current
V
TMR
ΔV
TMR
V
IN+
I
IN+
V
OL
I
OUT
ΔV
OUT
V
SHDN
TMR Pin Thresholds
Early Warning Period
IN
+
Pin Threshold
IN
+
Pin Input Current
FLT,
EN, A
OUT
Pins Output Low
OUT Pin Input Current
OUT Pin High Threshold
SHDN
Pin Threshold
–1.5
–44
–3.5
–2.5
–195
1.5
1.22
0.48
80
1.22
–2.5
–50
–5.5
–4.5
–260
2.2
1.25
0.5
100
1.25
0.3
2
300
200
6
0.5
1.4
1.2
–4
2
0.25
0.25
0.6
0.4
0.6
–1
V
SHDN(FLT)
SHDN
Pin Float Voltage
SHDN
Pin Current
I
SHDN
Overcurrent Turn-Off Delay Time
t
OFF(OC
)
t
OFF(OV)
Overvoltage Turn-Off Delay Time
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 the GATE pin to a minimum of 10V above
the OUT pin. Driving this pin to voltages beyond the clamp may damage
the device.
4356mp12f
3
LT4356MP-1/LT4356MP-2
TYPICAL PERFORMANCE CHARACTERISTICS
Specifications are at V
CC
= 12V, T
A
= 25°C unless otherwise noted.
I
CC
(Shutdown) vs V
CC
60
50
40
I
CC
(μA)
I
CC
(μA)
30
20
10
0
0
10
20
30
40 50
V
CC
(V)
60
70
80
LT4356-1
120
100
80
60
40
20
0
0
10
20
30
40 50
V
CC
(V)
60
70
80
200
I
CC
(μA)
600
I
CC
(Shutdown) vs V
CC
LT4356-2
IN
+
= 1.3V
1000
I
CC
vs V
CC
800
400
0
0
10
20
30
40 50
V
CC
(V)
60
70
80
4356mp12 G01
4356mp12 G02
4356mp12 G03
I
CC
(Shutdown) vs Temperature
35
30
25
I
CC
(μA)
I
CC
(μA)
20
15
10
5
0
–50
LT4356-1
300
250
200
150
100
50
I
CC
(Shutdown) vs Temperature
LT4356-2
6
5
4
I
SHDN
(μA)
–25
25
75
0
50
TEMPERATURE (°C)
100
125
3
2
1
SHDN
Current vs Temperature
V
SHDN
= 0V
–25
25
75
0
50
TEMPERATURE (°C)
100
125
0
–50
0
–50
–25
25
75
0
50
TEMPERATURE (°C)
100
125
4356mp12 G04
4356mp12 G05
4356mp12 G06
GATE Pull-Up Current vs V
CC
40
35
30
I
GATE
(μA)
I
GATE
(μA)
25
20
15
10
5
0
0
10
20
30
40 50
V
CC
(V)
60
70
80
35
30
GATE Pull-Up Current
vs Temperature
V
GATE
= V
OUT
= 12V
220
200
I
GATE(DOWN)
(mA)
180
160
140
120
GATE Pull-Down Current
vs Temperature
OVERVOLTAGE CONDITION
V
FB
= 1.5V
25
20
15
10
5
0
–50
–25
25
75
0
50
TEMPERATURE (°C)
100
125
100
–50
–25
25
75
0
50
TEMPERATURE (°C)
100
125
4356mp12 G07
4356mp12 G08
4356mp12 G09
4356mp12f
4
LT4356MP-1/LT4356MP-2
TYPICAL PERFORMANCE CHARACTERISTICS
Specifications are at V
CC
= 12V, T
A
= 25°C unless otherwise noted.
GATE Pull-Down Current
vs Temperature
12
10
I
GATE(DOWN)
(mA)
8
ΔV
GATE
(V)
6
4
2
0
–50
OVERCURRENT CONDITION
ΔV
SNS
= 120mV
14
12
10
ΔV
GATE
(V)
8
6
4
2
0
0
2
4
6
10
I
GATE
(μA)
8
12
14
16
ΔV
GATE
vs I
GATE
V
OUT
= 12V
14
12
10
8
6
4
2
ΔV
GATE
vs Temperature
I
GATE
= –1μA
V
CC
= 8V
V
CC
= 4V
–25
25
75
0
50
TEMPERATURE (°C)
100
125
0
–50
–25
0
50
25
75
TEMPERATURE (°C)
100
125
4356mp12 G10
4356mp12 G11
4356mp12 G12
ΔV
GATE
vs V
CC
16
14
12
ΔV
GATE
(V)
10
8
6
4
2 I
GATE
= –1μA
V
OUT
= V
CC
0
0
10 20
8
0
30
40 50
V
CC
(V)
60
70
80
T
A
= 25°C
T
A
= 130°C
48
Overvoltage TMR Current
vs (V
CC
– V
OUT
)
OVERVOLTAGE CONDITION
V
OUT
= 5V
V
TMR
= 1V
40
32
I
TMR
(μA)
I
TMR
(μA)
0
10
20
30 40 50
V
CC
– V
OUT
(V)
60
70
80
24
16
280
Overcurrent TMR Current
vs (V
CC
– V
OUT
)
OVERCURRENT CONDITION
V
OUT
= 0V
240 V
TMR
= 1V
200
160
120
80
40
0
0
10
20
30 40 50
V
CC
– V
OUT
(V)
60
70
80
T
A
= –45°C
4356mp12 G13
4356mp12 G14
4356mp12 G15
Warning Period
TMR Current vs V
CC
14
OVERVOLTAGE, EARLY
WARNING PERIOD
12 V
FB
= 1.5V
V
TMR
= 1.3V
10
I
TMR
(μA)
I
TMR
(μA)
8
6
4
2
0
0
10
20
30
40 50
V
CC
(V)
60
70
80
3.0
2.5
2.0
TMR Pull-Down Current
vs Temperature
V
TMR
= 1V
4.0
3.5
3.0
2.5
V
OL
(V)
2.0
1.5
1.0
0.5
0
–50
0.5
0
–25
0
25
50
75
TEMPERATURE (°C)
100
125
Output Low Voltage vs Current
A
OUT
FLT
EN
1.5
1.0
0
0.5
1.0
1.5
2.0
CURRENT (mA)
2.5
3.0
4356mp12 G16
4356mp12 G17
4356mp12 G18
4356mp12f
5
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