1

LTC4412

4412f

APPLICATIO S

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

Low Loss PowerPath

TM

Controller in ThinSOT

s

Very Low Loss Replacement for Power Supply

OR’ing Diodes

s

Minimal External Components

s

Automatic Switching Between DC Sources

s

Simplifies Load Sharing with Multiple Batteries

s

Low Quiescent Current: 11

µA

s

3V to 28V AC/DC Adapter Voltage Range

s

2.5V to 28V Battery Voltage Range

s

Reverse Battery Protection

s

Drives Almost Any Size MOSFET for Wide Range of

Current Requirements

s

MOSFET Gate Protection Clamp

s

Manual Control Input

s

Low Profile (1mm) ThinSOT

s

Cellular Phones

s

Notebook and Handheld Computers

s

Digital Cameras

s

USB-Powered Peripherals

s

Uninterruptable Power Supplies

s

Logic Controlled Power Switch

The LTC

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 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

(11

µA 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

microcontroller 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.

, LTC and LT are registered trademarks of Linear Technology Corporation.

PowerPath and ThinSOT are trademarks of Linear Technology Corporation.

GND

CTL

SENSE

GATE

STAT

1

2

3

6

5

4

LTC4412

TO LOAD

STATUS OUTPUT

LOW WHEN WALL

ADAPTER PRESENT

470k

4412 F01

1N5819

FDN306P

BATTERY

CELL(S)

WALL

ADAPTER

INPUT

Figure 1. Automatic Switchover of Load Between a Battery and a Wall Adapter

FORWARD VOLTAGE (V)

0.02

0

1

CONSTANT

4412 F01b

0.5

CONSTANT

VOLTAGE

SCHOTTKY

DIODE

LTC4412

LTC4412 vs Schottky Diode

Forward Voltage Drop