create a near ideal diode function for power switchover
or load sharing. This permits highly efficient OR’ing of
multiple 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
automatically disconnected from the battery when the
auxiliary source is connected. Two or more LTC4412s
may be interconnected to allow load sharing between
multiple batteries or charging of multiple batteries from
a single charger.
The wide supply operating range supports operation
from one to six 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 mi-
crocontroller that an auxiliary supply is connected. The
control (CTL) input enables the user to force the primary
MOSFET off and the STAT pin low.
The LTC4412 is available in a low profile (1mm) ThinSOT
package.
n
n
n
Very Low Loss Replacement for Power Supply
OR’ing Diodes
Minimal External Components
Automatic Switching Between DC Sources
Simplifies Load Sharing with Multiple Batteries
Low Quiescent Current: 11µA
3V to 28V AC/DC Adapter Voltage Range
2.5V to 28V 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) ThinSOT™ Package
applicaTions
n
n
n
n
n
n
Cellular Phones
Notebook and Handheld Computers
Digital Cameras
USB-Powered Peripherals
Uninterruptible Power Supplies
Logic Controlled Power Switch
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks
are the property of their respective owners.
Typical applicaTion
1
LTC4412 vs Schottky Diode
Forward Voltage Drop
CONSTANT
R
ON
WALL
ADAPTER
INPUT
CURRENT (A)
BATTERY
CELL(S)
TO LOAD
LTC4412
V
IN
SENSE
GND
CTL
GATE
STAT
C
OUT
V
CC
470k
4412 F01
LTC4412
CONSTANT
VOLTAGE
STATUS OUTPUT
LOW WHEN WALL
ADAPTER PRESENT
SCHOTTKY
DIODE
Figure 1. Automatic Switchover of Load Between a Battery and a Wall Adapter
0
0.02
FORWARD VOLTAGE (V)
0.5
4412 F01b
4412fb
For more information
www.linear.com/LTC4412
1
LTC4412
absoluTe MaxiMuM raTings
(Note 1)
pin conFiguraTion
TOP VIEW
V
IN
1
GND 2
CTL 3
6 SENSE
5 GATE
4 STAT
Supply Voltage (V
IN
) .................................. –14V to 36V
Voltage from V
IN
to SENSE ........................ – 28V to 28V
Input Voltage
CTL ........................................................– 0.3V to 36V
SENSE .................................................... –14V to 36V
Output Voltage
GATE ..................... –0.3V to the Higher of V
IN
+ 0.3V
or SENSE + 0.3V
STAT ......................................................– 0.3V to 36V
Operating Junction Temperature Range
(Note 2) ........................................... – 55°C to 150°C
Storage Temperature Range...................–65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
S6 PACKAGE
6-LEAD PLASTIC TSOT-23
T
JMAX
= 150°C,
θ
JA
= 230°C/W
orDer inForMaTion
LEAD FREE FINISH
LTC4412ES6#PBF
LTC4412IS6#PBF
LTC4412HS6#PBF
LTC4412MPS6#PBF
LEAD BASED FINISH
LTC4412ES6
LTC4412IS6
LTC4412HS6
LTC4412MPS6
TAPE AND REEL
LTC4412ES6#TRPBF
LTC4412IS6#TRPBF
LTC4412HS6#TRPBF
LTC4412MPS6#TRPBF
TAPE AND REEL
LTC4412ES6#TR
LTC4412IS6#TR
LTC4412HS6#TR
LTC4412MPS6#TR
PART MARKING*
LTA2
LTA2
LTA2
LTA2
PART MARKING*
LTA2
LTA2
LTA2
LTA2
PACKAGE DESCRIPTION
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
PACKAGE DESCRIPTION
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
6-Lead Plastic TSOT-23
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
–40°C to 150°C
–55°C to 150°C
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
–40°C to 150°C
–55°C to 150°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
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/
2
4412fb
For more information
www.linear.com/LTC4412
LTC4412
elecTrical characTerisTics
SYMBOL
V
IN
,
V
SENSE
I
QFL
I
QFH
I
QRL
I
QRH
I
QCL
I
QCH
I
LEAK
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
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
The
l
denotes the specifications which apply over the full operating
junction 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
= 28V. Measure Combined Current
at V
IN
and SENSE Pins Averaged with
V
SENSE
= 27.9V and V
SENSE
= 28V (Note 3)
V
IN
= 3.6V, V
SENSE
= 3.7V. Measure
Combined Current of V
IN
and SENSE Pins
V
IN
= 27.9V, V
SENSE
= 28V. Measure
Combined Current of V
IN
and SENSE Pins
V
IN
= 3.6V, V
SENSE
= 0V, V
CTL
= 1V
V
IN
= 28V, V
SENSE
= 0V, 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
≤ 28V
V
SENSE
– V
IN
, 2.5V ≤ V
IN
≤ 28V
l
l
l
l
MIN
2.5
TYP
MAX
28
UNITS
V
µA
11
19
l
15
26
µA
10
16
7
12
–3
0
19
28
13
20
1
µA
µA
µA
µA
µA
PowerPath Controller
V
FR
V
RTO
10
10
20
20
32
32
mV
mV
GATE and STAT Outputs
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
2.5V ≤ V
IN
≤ 28V
2.5V ≤ V
IN
≤ 28V
0.35V ≤ V
CTL
≤ 28V
2.5V ≤ V
IN
≤ 28V
l
l
(Note 4)
–1
25
6.3
–2.5
50
7
0.13
110
13
–5
85
7.7
0.25
175
22
1
17
25
75
0.35
5.5
µA
µA
V
V
µs
µs
µA
µA
µs
µs
V
V
µA
mV
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
≤ 28V (Note 7)
2.5V ≤ V
IN
≤ 28V (Note 7)
(Note 8)
(Note 8)
l
l
–1
6
0
10
4.5
40
0.5
0.9
1
0.635
3.5
135
4412fb
For more information
www.linear.com/LTC4412
3
LTC4412
elecTrical characTerisTics
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:
The LTC4412 is tested under pulsed load conditions such that T
J
≈
T
A
. The LTC4412E is guaranteed to meet performance specifications from
0°C to 85°C operating junction temperature range. Specifications over
the –40°C to 85°C operating junction temperature range are assured by
design, characterization and correlation with statistical process controls.
The LTC4412I is guaranteed over the –40°C to 85°C operating junction
temperature range. The LTC4412MP is tested and guaranteed over the
–55°C to 150°C operating junction temperature range. High junction
temperatures degrade operating lifetimes; operating lifetime is degraded
for junction temperatures greater than 125°C. Note that the maximum
ambient temperature consistent with these specifications is determined
by specific operating conditions in conjunction with board layout, the
rated package thermal impedance and other environmental factors. T
J
is calculated from the ambient temperature T
A
and power dissipation P
D
according to the following formula: T
J
= T
A
+ (P
D
•
Θ
JA
), where
Θ
JA
=
230°C/W for the TSOT-23 package.
Note 3:
This results in the same supply current as would be observed with
an external P-channel MOSFET connected to the LTC4412 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
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