FEATURES
n Very Low Loss Replacement for Power Supply
OR’ing Diodes
n Minimal External Components
n Automatic Switching Between DC Sources
n Simplifies Load Sharing with Multiple Batteries
n Low Quiescent Current: 11µA
n 3V to 28V AC/DC Adapter Voltage Range
n 2.5V to 28V Battery Voltage Range
n Reverse Battery Protection
n Drives Almost Any Size MOSFET for Wide Range of
Current Requirements
n MOSFET Gate Protection Clamp
n Manual Control Input
n Low Profile (1mm) ThinSOT™ Package
n AEC-Q100 Qualified for Automotive Applications
APPLICATIONS
n Cellular Phones
n Notebook and Handheld Computers
n Digital Cameras
n USB-Powered Peripherals
n Uninterruptible Power Supplies
n Logic Controlled Power Switch
All registered trademarks and trademarks are the property of their respective owners.
LTC4412
Low Loss PowerPath™
Controller in ThinSOT
DESCRIPTION
The LTC®4412 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
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.
TYPICAL APPLICATION
WALL
ADAPTER
INPUT
BATTERY
CELL(S)
LTC4412
VIN SENSE
GND GATE
CTL STAT
COUT
VCC
TO LOAD
470k STATUS OUTPUT
LOW WHEN WALL
4412 F01 ADAPTER PRESENT
Figure 1. Automatic Switchover of Load Between a Battery and a Wall Adapter
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LTC4412 vs Schottky Diode
Forward Voltage Drop
1
CONSTANT
RON
LTC4412
CONSTANT
VOLTAGE
SCHOTTKY
DIODE
0
0.02
FORWARD VOLTAGE (V)
0.5
4412 F01b
Rev. C
1
