LTC4412HV
36V, Low Loss PowerPath
TM
Controller in ThinSOT
DESCRIPTIO
The LTC
®
4412HV controls an external P-channel MOSFET
to create a near ideal diode function for power switchover
or load sharing. This permits highly efficient OR’ing of mul-
tiple power sources for extended battery life and low self-
heating. When conducting, the voltage drop across the
MOSFET is typically 20mV. For applications with a wall
adapter or other auxiliary power source, the load is auto-
matically disconnected from the battery when the auxiliary
source is connected. Two or more LTC4412HVs may be in-
terconnected to allow load sharing between multiple bat-
teries or charging of multiple batteries from a single charger.
The LTC4412HV is an extended supply and temperature
range version of the LTC4412.
The wide supply operating range supports operation from
one to eight Li-Ion cells in series. The low quiescent
current (11µA typical) is independent of the load current.
The gate driver includes an internal voltage clamp for
MOSFET protection.
The STAT pin can be used to enable an auxiliary P-channel
MOSFET power switch when an auxiliary supply is
detected. This pin may also be used to indicate to a micro-
controller that an auxiliary supply is connected. The con-
trol (CTL) input enables the user to force the primary
MOSFET off and the STAT pin low.
The LTC4412HV is available in a low profile (1mm) SOT-23
package.
FEATURES
s
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s
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Very Low Loss Replacement for Power Supply
OR’ing Diodes
3V to 36V AC/DC Adapter Voltage Range
–40°C to 125°C Operating Temperature Range
Minimal External Components
Automatic Switching Between DC Sources
Simplifies Load Sharing with Multiple Batteries
Low Quiescent Current: 11µA
2.5V to 36V Battery Voltage Range
Reverse Battery Protection
Drives Almost Any Size MOSFET for Wide Range of
Current Requirements
MOSFET Gate Protection Clamp
Manual Control Input
Low Profile (1mm) SOT-23 (ThinSOT
TM
) Package
APPLICATIO S
s
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Industrial and Automotive Applications
Notebook and Handheld Computers
USB-Powered Peripherals
Uninterruptable Power Supplies
Logic Controlled Power Switch
, LTC and LT are registered trademarks of Linear Technology Corporation.
PowerPath and ThinSOT are trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
WALL
ADAPTER
INPUT
BATTERY
CELL(S)
1N5819
LTC4412HV vs Schottky Diode Forward Voltage Drop
1
CONSTANT
R
ON
CURRENT (A)
FDN306P
TO LOAD
LTC4412HV
6
1
V
IN
SENSE
5
2
GND GATE
4
3
CTL STAT
C
OUT
V
CC
470k
4412HV F01
STATUS OUTPUT
LOW WHEN WALL
ADAPTER PRESENT
Figure 1. Automatic Switchover of Load Between a Battery and a Wall Adapter
0
0.02
FORWARD VOLTAGE (V)
0.5
4412HV F01b
U
U
U
LTC4412HV
CONSTANT
VOLTAGE
SCHOTTKY
DIODE
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1
LTC4412HV
ABSOLUTE
MAXIMUM
RATINGS
(Note 1)
PACKAGE/ORDER INFORMATION
ORDER PART
NUMBER
TOP VIEW
V
IN
1
GND 2
CTL 3
6 SENSE
5 GATE
4 STAT
Supply Voltage (V
IN
) .................................. –14V to 40V
Voltage from V
IN
to SENSE ........................ – 40V to 40V
Input Voltage
CTL ........................................................– 0.3V to 40V
SENSE .................................................... –14V to 40V
Output Voltage
GATE ..................... –0.3V to the Higher of V
IN
+ 0.3V
or SENSE + 0.3V
STAT .....................................................– 0.3V to 40V
Operating Ambient Temperature Range
(Note 2) ........................................... – 40°C to 125°C
Operating Junction Temperature ......... – 40°C to 125°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
LTC4412HVIS6
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
T
JMAX
= 125°C,
θ
JA
= 230°C/W
S6 PART MARKING
LTBHR
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
SYMBOL
V
IN
,
V
SENSE
I
QFL
PARAMETER
Operating Supply Range
Quiescent Supply Current at Low Supply
While in Forward Regulation
Quiescent Supply Current at High Supply
While in Forward Regulation
Quiescent Supply Current at Low Supply
While in Reverse Turn-Off
Quiescent Supply Current at High Supply
While in Reverse Turn-Off
Quiescent Supply Current at Low Supply
with CTL Active
Quiescent Supply Current at High Supply
with CTL Active
V
IN
and SENSE Pin Leakage Currents
When Other Pin Supplies Power
PowerPath Switch Forward Regulation
Voltage
PowerPath Switch Reverse Turn-Off
Threshold Voltage
The
q
denotes specifications which apply over the full operating
temperature range, unless otherwise noted specifications are at T
A
= 25°C, V
IN
= 12V, CTL and GND = 0V. Current into a pin is positive
and current out of a pin is negative. All voltages are referenced to GND, unless otherwise specified.
CONDITIONS
V
IN
and/or V
SENSE
Must Be in This Range
for Proper Operation
V
IN
= 3.6V. Measure Combined Current
at V
IN
and SENSE Pins Averaged with
V
SENSE
= 3.5V and V
SENSE
= 3.6V (Note 3)
V
IN
= 36V. Measure Combined Current
at V
IN
and SENSE Pins Averaged with
V
SENSE
= 35.9V and V
SENSE
= 36V (Note 3)
V
IN
= 3.6V, V
SENSE
= 3.7V. Measure
Combined Current of V
IN
and SENSE Pins
V
IN
= 35.9V, V
SENSE
= 36V. Measure
Combined Current of V
IN
and SENSE Pins
V
IN
= 3.6V, V
SENSE
= 0V, V
CTL
= 1V
V
IN
= 36V, V
SENSE
= 8V, V
CTL
= 1V
V
IN
= 28V, V
SENSE
= 0V; V
SENSE
= 28V, V
IN
= 0V
V
IN
= 14V, V
SENSE
= –14V; V
SENSE
= 14V, V
IN
= –14V
V
IN
– V
SENSE
, 2.5V
≤
V
IN
≤
36V
V
SENSE
– V
IN
, 2.5V
≤
V
IN
≤
36V
q
q
q
q
MIN
2.5
TYP
MAX
36
UNITS
V
µA
11
19
I
QFH
q
18
32
I
QRL
I
QRH
I
QCL
I
QCH
I
LEAK
10
19
7
15
–3
0
19
33
13
25
1
PowerPath Controller
V
FR
V
RTO
10
10
20
20
32
32
mV
mV
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U
W
U
U
W W
W
µA
µA
µA
µA
µA
µA
LTC4412HV
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
GATE Active Forward Regulation
Source Current
Sink Current
GATE Clamp Voltage
GATE Off Voltage
GATE Turn-On Time
GATE Turn-Off Time
STAT Off Current
STAT Sink Current
STAT Turn-On Time
STAT Turn-Off Time
CTL Input Low Voltage
CTL Input High Voltage
CTL Input Pull-Down Current
CTL Hysteresis
GATE and STAT Outputs
The
q
denotes specifications which apply over the full operating
temperature range, unless otherwise noted specifications are at T
A
= 25°C, V
IN
= 12V, CTL and GND = 0V. Current into a pin is positive
and current out of a pin is negative. All voltages are referenced to GND, unless otherwise specified.
CONDITIONS
(Note 4)
–1
25
Apply I
GATE
= 1µA, V
IN
= 12V,
V
SENSE
= 11.9V, Measure V
IN
– V
GATE
Apply I
GATE
= – 5µA, V
IN
= 12V,
V
SENSE
= 12.1V, Measure V
SENSE
– V
GATE
V
GS
< –3V, C
GATE
= 1nF (Note 5)
V
GS
> –1.5V, C
GATE
= 1nF (Note 6)
2.5V
≤
V
IN
≤
36V (Note 7)
2.5V
≤
V
IN
≤
36V (Note 7)
(Note 8)
(Note 8)
2.5V
≤
V
IN
≤
36V
2.5V
≤
V
IN
≤
36V
0.35V
≤
V
CTL
≤
36V
2.5V
≤
V
IN
≤
36V
q
q
q
q
MIN
TYP
MAX
UNITS
I
G(SRC)
I
G(SNK)
V
G(ON)
V
G(OFF)
t
G(ON)
t
G(OFF)
I
S(OFF)
I
S(SNK)
t
S(ON)
t
S(OFF)
CTL Input
V
IL
V
IH
I
CTL
H
CTL
–2.5
50
7
0.13
110
13
–5
85
7.7
0.25
175
22
1
17
25
75
0.35
µA
µA
V
V
µs
µs
µA
µA
µs
µs
V
V
µA
mV
6.3
–1
6
0
10
4.5
40
0.9
1
3.5
135
5.9
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
The LTC4412HV is guaranteed to meet performance specifications
over the – 40°C to 125°C operating ambient temperature range.
Note 3:
This results in the same supply current as would be observed with
an external P-channel MOSFET connected to the LTC4412HV and
operating in forward regulation.
Note 4:
V
IN
is held at 12V and GATE is forced to 10.5V. SENSE is set at
12V to measure the source current at GATE. SENSE is set at 11.9V to
measure sink current at GATE.
Note 5:
V
IN
is held at 12V and SENSE is stepped from 12.2V to 11.8V to
trigger the event. GATE voltage is initially V
G(OFF)
.
Note 6:
V
IN
is held at 12V and SENSE is stepped from 11.8V to 12.2V to
trigger the event. GATE voltage is initially internally clamped at V
G(ON)
.
Note 7:
STAT is forced to V
IN
– 1.5V. SENSE is set at V
IN
– 0.1V to
measure the off current at STAT. SENSE is set V
IN
+ 0.1V to measure the
sink current at STAT.
Note 8:
STAT is forced to 9V and V
IN
is held at 12V. SENSE is stepped
from 11.8V to 12.2V to measure the STAT turn-on time defined when I
STAT
reaches one half the measured I
S(SNK).
SENSE is stepped from 12.2V to
11.8V to measure the STAT turn-off time defined when I
STAT
reaches one
half the measured I
S(SNK) .
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LTC4412HV
TYPICAL PERFOR A CE CHARACTERISTICS
V
FR
vs Temperature and
Supply Voltage
22
22
V
IN
= 2.5V
20
V
IN
= 28V
V
RTO
(mV)
V
FR
(mV)
V
IN
= 28V
20
V
IN
= 2.5V
CURRENT (µA)
V
IN
= 36V
18
–50 –25
50
25
75
0
TEMPERATURE (°C)
V
IN
and SENSE Pin Leakages vs
Temperature and Supply Voltage
0
I
LEAK
7.1
–1
CURRENT (µA)
VOLTAGE (V)
VOLTAGE (V)
I
VIN
: V
SENSE
= 36V, V
IN
= 0V
–2
I
VIN
: V
SENSE
= 24V, V
IN
= –14V
–3
I
SENSE
: V
IN
= 36V, V
SENSE
= 0V
–4
I
SENSE
: V
IN
= 24V, V
SENSE
= –14V
–5
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
t
G(ON)
vs Temperature and
Supply Voltage
120
V
IN
= 12V
14
15
V
IN
= 24V
110
TIME (µs)
V
IN
= 30V
TIME (µs)
CURRENT (µA)
100
V
IN
= 36V
11
90
–50 –25
50
25
75
0
TEMPERATURE (°C)
4
U W
100
V
RTO
vs Temperature and
Supply Voltage
1.05
Normalized Quiescent Supply
Current vs Temperature
V
IN
= 36V
3.6V
≤
V
IN
≤
36V
1.0
125
18
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
0.95
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
4412HV G01
4412HV G02
4412HV G03
V
G(ON)
vs Temperature
8V
≤
V
IN
≤
36V
I
GATE
= 1µA
0.25
V
G(OFF)
vs Temperature and I
GATE
2.5V
≤
V
IN
≤
36V
0.20
I
GATE
= –10µA
0.15
I
GATE
= –5µA
0.10
I
GATE
= 0µA
7.0
0.05
6.9
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
0
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
4412HV G04
4412HV G05
4412HV G06
t
G(OFF)
vs Temperature and
Supply Voltage
10.5
I
S(SNK)
vs Temperature and V
IN
V
STAT
= V
IN
– 1.5V
V
IN
= 12V
13
V
IN
= 36V
V
IN
= 36V
10.0
V
IN
= 2.5V
12
100
125
10
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
9.5
–50 –25
50
25
75
0
TEMPERATURE (°C)
100
125
4412HV G07
4412HV G08
4412HV G09
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LTC4412HV
PI FU CTIO S
V
IN
(Pin 1):
Primary Input Supply Voltage. Supplies power
to the internal circuitry and is one of two voltage sense
inputs to the internal analog controller (The other input to
the controller is the SENSE pin). This input is usually
supplied power from a battery or other power source
which supplies current to the load. This pin can be by-
passed to ground with a capacitor in the range of 0.1µF to
10µF if needed to suppress load transients.
GND (Pin 2):
Ground. Provides a power return for all the
internal circuits.
CTL (Pin 3):
Digital Control Input. A logical high input (V
IH
)
on this pin forces the gate to source voltage of the primary
P-channel MOSFET power switch to a small voltage (V
GOFF
).
This will turn the MOSFET off and no current will flow from
the primary power input at V
IN
if the MOSFET is configured
so that the drain to source diode does not forward bias. A
high input also forces the STAT pin to sink 10µA of current
(I
S(SNK)
). If the STAT pin is used to control an auxiliary P-
channel power switch, then a second active source of
power, such as an AC wall adaptor, will be connected to the
load (see Applications Information). An internal current
sink will pull the CTL pin voltage to ground (logical low) if
the pin is open.
STAT (Pin 4):
Open-Drain Output Status Pin. When the
SENSE pin is pulled above the V
IN
pin with an auxiliary
power source by about 20mV or more, the reverse turn-off
threshold (V
RTO
) is reached. The STAT pin will then go
from an open state to a 10µA current sink (I
S(SNK)
). The
STAT pin current sink can be used, along with an external
resistor, to turn on an auxiliary P-channel power switch
and/or signal the presence of an auxiliary power source to
a microcontroller.
GATE (Pin 5):
Primary P-Channel MOSFET Power Switch
Gate Drive Pin. This pin is directed by the power controller
to maintain a forward regulation voltage (V
FR
) of 20mV
between the V
IN
and SENSE pins when an auxiliary power
source is not present. When an auxiliary power source is
connected, the GATE pin will pull up to the SENSE pin
voltage, turning off the primary P-channel power switch.
SENSE (Pin 6):
Power Sense Input Pin. Supplies power to
the internal circuitry and is a voltage sense input to the
internal analog controller (The other input to the controller
is the V
IN
pin). This input is usually supplied power from
an auxiliary source such as an AC adapter or back-up
battery which also supplies current to the load.
AUXILIARY
SUPPLY
PRIMARY
SUPPLY
1
V
IN
6
SENSE
POWER SOURCE
SELECTOR
POWER
VOLTAGE/CURRENT
REFERENCE
0.5V
A1
LINEAR GATE
DRIVER AND
VOLTAGE CLAMP
GATE
5
V
CC
ON/OFF
3
CTL
3.5µA
+
C1
ANALOG CONTROLLER
ON/OFF
10µA
STAT
4
STATUS
OUTPUT
–
2
GND
*DRAIN-SOURCE DIODE OF MOSFET
4412HV BD
–
+
+
–
–
+
BLOCK DIAGRA
–
+
W
U
U
U
OUTPUT
TO LOAD
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