LTC4231
Micropower Hot Swap
Controller
FeaTures
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DescripTion
The
LTC
®
4231
is a micropower Hot Swap™ controller that
allows safe circuit board insertion and removal from a live
power supply. An internal high side switch driver controls
the gate of an external N-channel MOSFET. Back-to-back
MOSFETs can be used for reverse supply protection down
to –40V.
The LTC4231 provides a debounce delay and allows the
GATE to be ramped up at an adjustable rate. After start-
up, the LTC4231's quiescent current drops to 4µA during
normal operation with output active. UVL, UVH, OV and
GNDSW monitor overvoltage and undervoltage periodi-
cally, keeping total quiescent current low. Pulling
SHDN
low shuts down the LTC4231 and quiescent current drops
to 0.3µA.
During an overcurrent fault, the LTC4231 actively limits
current while running an adjustable timer. The LTC4231-1
remains off after a current fault while the LTC4231-2
automatically reapplies power after a cool-down period.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and Hot
Swap and PowerPath are trademarks of Linear Technology Corporation. All other trademarks are
the property of their respective owners.
Enables Safe Board Insertion and Removal from a
Power Supply
4µA Supply Current
0.3µA Shutdown Current
Wide Operating Voltage Range: 2.7V to 36V
Reverse Supply Protection to –40V
Adjustable Analog Current Limit with Circuit Breaker
Automatic Retry or Latchoff on Current Fault
Overvoltage and Undervoltage Monitoring
Controls Single or Back-to-Back N-Channel MOSFETs
12-Lead MSOP and 3mm × 3mm QFN Packages
applicaTions
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Battery Powered Equipment
Solar Powered Systems
Portable Instruments
Automotive Battery Protection
Energy Harvesting
Typical applicaTion
Battery Hot Swap with Reverse Protection
SMAJ24CA
22.5m
Si7164DP
Si5410DU
V
OUT
24V
2A
220µF
SENSE
1020k
24V
1.65k
UVH
4.22k
OV
32.4k
GNDSW
GND
TIMER
180nF
SHDN
IN
UVL
LTC4231
GATE
SOURCE
STATUS
SOURCE
20V/DIV
I
LOAD
5A/DIV
10ms/DIV
4231 TA01b
Power-Up Waveforms
CONTACT
BOUNCE
IN
20V/DIV
GATE
20V/DIV
20k
4231 TA01a
4321fa
For more information
www.linear.com/LTC4231
1
LTC4231
absoluTe MaxiMuM raTings
(Notes 1, 2)
Supply Voltage
IN ............................................................ –40V to 40V
Input Voltages
SENSE, SOURCE ..................................... –40V to 40V
IN–SENSE ............................................... –40V to 40V
SHDN,
UVL, UVH, OV, GNDSW.............. –0.3V to 40V
Input Currents
SHDN,
UVL, UVH, OV, GNDSW (Note 3) ............–1mA
Output Voltages
GATE–SOURCE (Note 4) .........................–0.3V to 13V
GATE–SENSE .......................................... –40V to 20V
STATUS ................................................. –0.3V to 40V
TIMER ...................................................... –0.3V to 4V
Operating Ambient Temperature Range
LTC4231C ................................................ 0°C to 70°C
LTC4231I..............................................–40°C to 85°C
LTC4231H .......................................... –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)
MSOP Package ................................................. 300°C
pin conFiguraTion
TOP VIEW
SENSE
GATE
IN
12 11 10
SHDN
1
UVL 2
UVH 3
4
OV
5
GNDSW
6
GND
13
9 SOURCE
8 TIMER
7 STATUS
SENSE
IN
SHDN
UVL
UVH
OV
1
2
3
4
5
6
TOP VIEW
12
11
10
9
8
7
GATE
SOURCE
TIMER
STATUS
GND
GNDSW
MS PACKAGE
12-LEAD PLASTIC MSOP
T
JMAX
= 150°C,
θ
JA
= 135°C/W
UD PACKAGE
12-LEAD (3mm
×
3mm) PLASTIC QFN
T
JMAX
= 150°C,
θ
JA
= 68°C/W
EXPOSED PAD (PIN 13) PCB CONNECTION TO GND IS OPTIONAL
orDer inForMaTion
LEAD FREE FINISH
LTC4231CUD-1#PBF
LTC4231CUD-2#PBF
LTC4231IUD-1#PBF
LTC4231IUD-2#PBF
LTC4231HUD-1#PBF
LTC4231HUD-2#PBF
TAPE AND REEL
LTC4231CUD-1#TRPBF
LTC4231CUD-2#TRPBF
LTC4231IUD-1#TRPBF
LTC4231IUD-2#TRPBF
LTC4231HUD-1#TRPBF
LTC4231HUD-2#TRPBF
PART MARKING
LGMX
LGSP
LGMX
LGSP
LGMX
LGSP
PACKAGE DESCRIPTION
12-Lead (3mm × 3mm) Plastic QFN
12-Lead (3mm × 3mm) Plastic QFN
12-Lead (3mm × 3mm) Plastic QFN
12-Lead (3mm × 3mm) Plastic QFN
12-Lead (3mm × 3mm) Plastic QFN
12-Lead (3mm × 3mm) Plastic QFN
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
2
4321fa
For more information
www.linear.com/LTC4231
LTC4231
orDer inForMaTion
LEAD FREE FINISH
LTC4231CMS-1#PBF
LTC4231CMS-2#PBF
LTC4231IMS-1#PBF
LTC4231IMS-2#PBF
LTC4231HMS-1#PBF
LTC4231HMS-2#PBF
TAPE AND REEL
LTC4231CMS-1#TRPBF
LTC4231CMS-2#TRPBF
LTC4231IMS-1#TRPBF
LTC4231IMS-2#TRPBF
LTC4231HMS-1#TRPBF
LTC4231HMS-2#TRPBF
PART MARKING
42311
42312
42311
42312
42311
42312
PACKAGE DESCRIPTION
12-Lead Plastic MSOP
12-Lead Plastic MSOP
12-Lead Plastic MSOP
12-Lead Plastic MSOP
12-Lead Plastic MSOP
12-Lead Plastic MSOP
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
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on nonstandard 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/
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. IN = 12V, unless otherwise noted.
SYMBOL
IN
V
IN
V
IN(UVL)
∆V
IN(HYST)
I
CC
Input Supply Voltage Range
Input Supply Undervoltage Lockout
Input Supply Undervoltage Lockout
Hysteresis
Supply Current (Average)
Normal On, Voltage or Current Fault
Start-Up or Overcurrent
Shutdown
Reverse Input
SENSE
∆V
SENSE(CB)
∆V
SENSE(ACL)
I
SENSE
GATE, SOURCE
∆V
GATE
∆V
GATE(H)
V
GATE(L)
I
GATE(UP)
I
GATE(FAST)
I
GATE(SLOW)
t
D(ON)
t
RETRY
t
PHL(ILIM)
External N-Channel Gate Drive
(V
GATE
– V
SOURCE
)
∆V
GATE
(V
GATE
– V
SOURCE
) Threshold
That Deactivates the Charge Pump
GATE Low Threshold
GATE Pull-Up Current
GATE Fast Pull-Down Current
GATE Slow Pull-Down Current
Turn-On Debounce Delay
Auto-Retry Delay
Overcurrent to GATE Low Propagation
Delay
V
IN
< 7V, I
GATE
= 0, –0.1µA
V
IN
≥ 7V, I
GATE
= 0, –0.1µA
V
IN
< 7V
V
IN
≥ 7V
To Enter Shutdown or Voltage Fault
GATE On, GATE = 1V
∆V
SENSE
= 0.5V, ∆V
GATE
= 5V
SHDN
= 0V, ∆V
GATE
= 5V
UVL = UVH = 2V, OV = 0V,
SHDN
= Step 0V to 5V
LTC4231-2
∆V
SENSE
= Step 0mV to 300mV,
C
GATE
= 1nF, ∆V
GATE
Crosses 1V
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elecTrical characTerisTics
PARAMETER
CONDITIONS
MIN
2.7
2
TYP
MAX UNITS
36
V
V
mV
10
20
600
1
2
–5
53
90
1
10
18
10
18
1.8
–13
µA
µA
µA
µA
µA
mA
mV
mV
µA
V
V
V
V
V
µA
mA
mA
60
0.73
1
ms
s
µs
IN Rising
l
2.3
200
2.6
(Note 5)
I
GATE
≤ –0.1µA, C
GATE-SOURCE
= 1nF, (C-Grade, I-Grade)
(H-Grade)
SHDN
Low, GATE Pulled to GND, (C-Grade, I-Grade)
(H-Grade)
IN, SENSE = –40V
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4
4
300
0.3
0.3
–2.5
47
65
50
80
0.3
4.5
10
5.5
11
0.4
–7
70
0.6
20
0.27
6.2
11.4
6.5
11.7
1.2
–10
130
1
40
0.5
0.5
Circuit Breaker Threshold (V
IN
– V
SENSE
)
Analog Current Limit
SENSE Input Current
During Output Short-Circuit
SHDN
= High, SENSE = 12V
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4321fa
For more information
www.linear.com/LTC4231
3
LTC4231
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. IN = 12V, unless otherwise noted.
SYMBOL
V
UV
V
OV
V
OV(HYST)
I
LEAK(0.9V)
I
LEAK(12V)
R
ON(GNDSW)
V
OL
V
SHDN
t
PERIOD
t
SAMPLE
TIMER
t
CB
V
TIMER(H)
V
TIMER(L)
I
TIMER(UP)
I
TIMER(DN)
Circuit Breaker Delay
TIMER High Threshold
TIMER Low Threshold
TIMER Pull-Up Current
TIMER Pull-Down Current
C
T
= 100nF
TIMER Rising
TIMER Falling
TIMER = 0.5V, Circuit Breaker Tripped
TIMER = 0.5V, Circuit Breaker Recovery
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elecTrical characTerisTics
PARAMETER
UVL, UVH Threshold
OV Threshold
OV Hysteresis
UVL, UVH and OV Leakage Current
UVL, UVH, OV, GNDSW, STATUS and
SHDN
Leakage Current
Switch Resistance
STATUS Output Low Voltage
SHDN
Input Threshold
Sampling Period
Sampling Width
CONDITIONS
l
MIN
0.776
0.776
3
TYP
MAX UNITS
V
V
mV
nA
nA
nA
nA
Ω
V
V
ms
µs
ms
V
V
µA
µA
UVL, UVH, OV, GNDSW, STATUS and
SHDN
0.795 0.814
0.795 0.814
15
0
0
0
0
80
0.2
0.4
5
100
1.7
1.170
0.07
–35
3
0.8
10
200
2.4
0.1
–50
5
30
±10
±100
±100
±500
200
0.4
1.5
15
300
3.5
0.13
–65
7
OV Rising
V = 0.9V (C-Grade, I-Grade)
(H-Grade)
V = 12V (C-Grade, I-Grade)
(H-Grade)
I = 2mA
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1.193 1.216
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:
These pins can be tied to voltages below –0.3V through a
resistance that limits the current below 1mA.
Note 4:
An internal clamp limits GATE to a minimum of 13V above
SOURCE. Driving this pin to voltages beyond this clamp may damage the
device.
Note 5:
For modes where GATE is pulled to GND, I
CC
= I
IN
+ I
SENSE
.
Else I
CC
= I
IN
+ I
SENSE
+ I
SOURCE
.
4
4321fa
For more information
www.linear.com/LTC4231
LTC4231
Typical perForMance characTerisTics
Average Supply Current vs IN
5
NORMAL ON
I
GATE
= –0.1µA
100
I
CC
(µA)
I
CC
(µA)
I
CC
(µA)
3
1000
Average Supply Current
(Normal On) vs GATE Leakage
V
IN
= 12V
100
Average Supply Current
vs Temperature
V
IN
= 12V
NORMAL ON
I
GATE
= –1µA
NORMAL ON
I
GATE
= –0.1µA
NORMAL ON
I
GATE
= 0
4
10
2
10
1
SHUTDOWN
0
0
10
20
V
IN
(V)
30
40
4231 G01
1
SHUTDOWN
1
–0.01
–0.1
–1
I
GATE
(µA)
–10
–100
4231 G02
0.1
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
4231 G03
Supply Current (Reverse Input)
vs IN
–3
14
∆V
GATE
(Average) vs IN
I
GATE
= –0.1µA
∆V
GATE
(Average)
vs GATE Leakage
16
14
12
∆V
GATE
(V)
10
8
6
4
2
V
IN
= 2.7V
V
IN
= 12V
12
–2
∆V
GATE
(V)
–1
6
0
I
CC
(mA)
10
8
0
–10
–20
V
IN
(V)
–30
–40
4231 G04
4
0
10
20
V
IN
(V)
30
40
4231 G05
0
0
–2
–4
–6
–8
I
GATE
(µA)
–10
–12
4231 G06
4321fa
For more information
www.linear.com/LTC4231
5
