LTC4412

Manufacturer Part NumberLTC4412
DescriptionLow Loss PowerPathTM Controller
ManufacturerLinear Technology
LTC4412 datasheet
 


1
Page 1
2
Page 2
3
Page 3
4
Page 4
5
Page 5
6
Page 6
7
Page 7
8
Page 8
9
Page 9
10
Page 10
11
12
Page 1/12

Download datasheet (186Kb)Embed
Next
FEATURES
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: 11 A
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
TM
Low Profile (1mm) ThinSOT
Package
U
APPLICATIO S
Cellular Phones
Notebook and Handheld Computers
Digital Cameras
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.
U
TYPICAL APPLICATIO
1N5819
WALL
ADAPTER
INPUT
FDN306P
BATTERY
CELL(S)
LTC4412
1
6
V
SENSE
IN
2
5
GND
GATE
3
4
CTL
STAT
Figure 1. Automatic Switchover of Load Between a Battery and a Wall Adapter
Low Loss PowerPath
Controller in ThinSOT
DESCRIPTIO
®
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 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 A 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.
1
TO LOAD
C
OUT
V
CC
470k
STATUS OUTPUT
LOW WHEN WALL
4412 F01
ADAPTER PRESENT
0
0.02
LTC4412
www.DataSheet4U.com
TM
U
LTC4412 vs Schottky Diode
Forward Voltage Drop
CONSTANT
R
ON
LTC4412
CONSTANT
VOLTAGE
SCHOTTKY
DIODE
0.5
FORWARD VOLTAGE (V)
4412 F01b
4412f
1

LTC4412 Summary of contents

  • Page 1

    ... 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 LOAD ...

  • Page 2

    ... V = 14V SENSE SENSE V – 2.5V V 28V IN SENSE IN V – 2.5V V 28V SENSE IN IN www.DataSheet4U.com U W INFORMATION ORDER PART NUMBER LTC4412ES6 TOP VIEW 6 SENSE 5 GATE 4 STAT S6 PART MARKING S6 PACKAGE = 125 C, = 230 C/W LTA2 JA MIN TYP MAX 2 ...

  • Page 3

    ... operating ambient temperature range are assured by design, characterization and correlation with statistical process controls. 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 held at 12V and GATE is forced to 10.5V. SENSE is set at IN 12V to measure the source current at GATE ...

  • Page 4

    ... LTC4412 W U TYPICAL PERFOR A CE CHARACTERISTICS V vs Temperature and FR Supply Voltage 2. 28V –50 – 100 TEMPERATURE ( C) 4412 G01 I vs Temperature LEAK –0.20 –0.25 –0.30 –0.35 – 100 –25 0 TEMPERATURE ( C) 4412 G04 t vs Temperature G(ON) 120 3.6V V 28V ...

  • Page 5

    ... SOURCE A1 0.5V + ON/OFF C1 ANALOG CONTROLLER – GND 2 *DRAIN-SOURCE DIODE OF MOSFET LTC4412 www.DataSheet4U.com pin with an auxiliary reached. The STAT pin will then go RTO and SENSE pins when an auxiliary power IN pin). This input is usually supplied power from + OUTPUT TO LOAD – LINEAR GATE ...

  • Page 6

    ... IN 6 The Power Source Selector will power the LTC4412 from the SENSE pin. As the SENSE voltage pulls above V 20mV, the Analog Controller will instruct the Linear Gate Driver and Voltage Clamp block to pull the GATE voltage up to turn off the P-channel MOSFET ...

  • Page 7

    ... U U APPLICATIO S I FOR ATIO Introduction The system designer will find the LTC4412 useful in a variety of cost and space sensitive power control applica- tions that include low loss diode OR’ing, fully automatic switchover from a primary to an auxiliary source of power, microcontroller controlled switchover from a primary to ...

  • Page 8

    ... Internal protection for the LTC4412 is provided to prevent damaging pin currents and excessive internal self heating during a fault condition. These fault conditions can be a result of any LTC4412 pins shorted to ground power source that is within the pin’s absolute maximum voltage ), the system is RTO limits ...

  • Page 9

    ... Should the wall adapter input be applied, the Schottky diode will pull up the SENSE pin, connected to the load, above the battery voltage and the LTC4412 will turn the MOSFET off. The STAT pin will then sink current indicating an auxiliary input is connected. The battery is now supplying no load current and all the load current flows through the Schottky diode ...

  • Page 10

    ... LTC4412 through the CTL input. Back-to- back MOSFETs are used so that the drain-source diode will not power the load when the MOSFET is turned off (dual MOSFETs in one package are commercially avail- able) ...

  • Page 11

    ... SENSE pin is grounded, the LTC4412 will apply maximum clamped gate drive voltage to the MOSFET. When the CTL pin is a logical high, the LTC4412 will turn off the MOSFET by pulling its gate voltage up to the supply input voltage and thus deny power to the load. The MOSFET is connected with its source connected to the power source ...

  • Page 12

    ... LTC4412 PACKAGE DESCRIPTIO 0.62 0.95 MAX REF 3.85 MAX 2.62 REF RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.20 BSC DATUM ‘A’ 0.30 – 0.50 REF NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6 ...