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LTC4411 2.6A Low Loss Ideal Diode in ThinSOTTM
FEATURES

DESCRIPTIO
Low Loss Replacement for PowerPathTM OR'ing Diodes Small Regulated Forward Voltage (28mV) 2.6A Maximum Forward Current Low Forward ON Resistance (140m Max) Low Reverse Leakage Current (<1A) 2.6V to 5.5V Operating Range Internal Current Limit Protection Internal Thermal Protection No External Active Components Pin-Compatible Monolithic Replacement for the LTC4412 Low Quiescent Current (40A) Low-Profile (1mm) 5-lead SOT-23 Package
The LTC(R)4411 is an ideal diode IC, capable of supplying up to 2.6A from an input voltage between 2.6V and 5.5V. The LTC4411 is housed in a 5-lead 1mm profile SOT-23 package. The LTC4411 contains a 140m P-channel MOSFET connecting IN to OUT. During normal forward operation, the drop across the MOSFET is regulated to as low as 28mV. Quiescent current is less than 40A for load currents up to 100mA. If the output voltage exceeds the input voltage, the MOSFET is turned off and less than 1A of reverse current flows from OUT to IN. Maximum forward current is limited to a constant 2.6A (typical) and internal thermal limiting circuits protect the part during fault conditions. An open-drain STAT pin indicates conduction status. The STAT pin can be used to drive an auxiliary P-channel MOSFET power switch connecting an alternate power source when the LTC4411 is not conducting forward current. An active-high control pin turns off the LTC4411 and reduces current consumption to less than 25A. When shut off, the LTC4411 indicates this condition with a low voltage on the status signal.
, LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT and PowerPath are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
APPLICATIO S

Cellular Phones Handheld Computers Digital Cameras USB Peripherals Uninterrupted Supplies Logic Controlled Power Switch
TYPICAL APPLICATIO
WALL ADAPTER INPUT IN BATTERY CELL(S) OUT LTC4411 GND CTL STAT
TO LOAD VCC 4.7F 470k
IMAX
IOC
LTC4411 SLOPE 1/RON CONSTANT RON
CURRENT (A)
STATUS OUTPUT IS LOW WHEN WALL ADAPTER IS SUPPLYING LOAD CURRENT
4411 F01
IFWD
Figure 1. Automatic Switchover of Load Between a Battery and a Wall Adapter
VFWD
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LTC4411 vs Schottky Diode Forward Voltage Characteristics
CONSTANT ION SLOPE 1/RFWD SCHOTTKY DIODE
LTC4411 FO1b
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CONSTANT VON
FORWARD VOLTAGE (V)
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LTC4411
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
ORDER PART NUMBER
TOP VIEW IN 1 GND 2 CTL 3 4 STAT 5 OUT
IN, OUT, STAT, CTL Voltage .......................... -0.3 to 6V Operating Ambient Temperature Range (Note 2) ...............................................-40C to 85C Operating Junction Temperature (Note 3) .............................................-40C to 125C Storage Temperature Range ..................-65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C Continuous Power Dissipation (Derate 10mW/C above 70C)...................... 500mW
LTC4411ES5 S5 PART MARKING LTAEN
S5 PACKAGE 5-LEAD PLASTIC SOT-23 TJMAX = 125C, JA = 250C/W (Note 3)
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 6)
SYMBOL VIN, VOUT IQF IQ(Off) IQRIN IQROUT ILEAK VFWD -VRTO RFWD RON UVLO PARAMETER Operating Supply Range Quiescent Current in Forward Regulation (Note 4) Quiescent Current in Shutdown Quiescent Current While in Reverse Turn-Off. Current Drawn from VIN Quiescent Current While in Reverse Turn-Off. Current Drawn from VOUT VIN Current When VOUT Supplies Power Forward Turn-On Voltage (VIN - VOUT) Reverse Turn-Off Voltage (VOUT - VIN) Forward ON Resistance, (VIN-VOUT)/(ILOAD) ON Resistance in Constant RON Mode Undervoltage Lockout CONDITIONS
ELECTRICAL CHARACTERISTICS
MIN 2.6
TYP 40
MAX 5.5
VIN = 3.6V, ILOAD = 100mA VIN = 3.6V, VSTAT = 0V, VCTL > VIH VIN = 3.6V VOUT = 3.7V VIN = 3.6V VOUT = 3.7V VIN = 0V, VOUT = 5.5V VIN = 3.6V VIN = 3.6V VIN = 3.6V, 100mA < ILOAD < 500mA VIN = 3.6V, ILOAD = 1000mA VIN Rising, 0C < TA < 85C VIN Rising VIN Falling VIN = 3.6V, VOUT > VIN + VRTO, VCTL > VTH + VHYST VIN = 3.6V, VOUT < VIN - VFWD, VCTL < VTH - VHYST

UNITS V A A A A A mV mV m m V V
V
1.3 14 -1 8 -4
22 1.8 17
25 2.3 23 1 28 14 140 245 2.5 2.6

17 5 100 140
1.6
STAT Output IS(SNK) IS(OFF) tS(ON) tS(OFF) CTL Input VTH VHYST ICTL IOC IQOC
STAT Pin Sink Current STAT Pin Off Current STAT Pin Turn-On Time STAT Pin Turn-Off Time CTL Input Threshold Voltage CTL Input Hysteresis CTL Input Pull-Down Current Current Limit Quiescent Current While in Overcurrent Operation
7 -1
11
18 1
1.2 1.1 VTH = (VIL + VIH)/2 VHYST = (VIH - VIL) VOUT < VIN = 3.6V, VCTL = 1.5V VIN = 3.6V (Note 5) VIN = 3.6V, IOUT = 1.8A

1.4 1.25 530 6
390 2 1.8
460 90 3.5 2.6 575
Short-Circuit Response A 1100 A
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A A s s mV mV A
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WW
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LTC4411
The denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. (Note 6)
Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LTC4411E is guaranteed to meet performance specifications from 0C to 70C. Specifications over the -40C to 85C ambient operating temperature range are assured by design, characterization and correlation with statistical process controls. Note 3: TJ is calculated from the ambient temperature TA and power dissipation PD according to the following formula: TJ = TA + (PD * 150C/W) The following table lists thermal resistance for several different board sizes and copper areas. All measurements were taken in still air on 3/32" FR-4 board with the device mounted on topside. Measured Thermal Resistance (2-Layer Board*) COPPER AREA TOPSIDE BACKSIDE 2500mm2 1000mm2 225mm2 100mm2 50mm2 2500mm2 2500mm2 2500mm2 2500mm2 2500mm2 BOARD AREA 2500mm2 2500mm2 2500mm2 2500mm2 2500mm2 THERMAL RESISTANCE JUNCTION-TO-AMBIENT 125C/W 125C/W 130C/W 135C/W 150C/W Note 4: Quiescent current increases with load current, refer to plot of IQF vs ILOAD. Note 5: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125C when overtemperature protection is active. Continuous operation above the specified maximum operating junction temperature may impair device reliability. Note 6: Current into a pin is positive and current out of a pin is negative. All voltages are referenced to GND.
ELECTRICAL CHARACTERISTICS
*Each layer uses one ounce copper
TYPICAL PERFOR A CE CHARACTERISTICS
Typical IQF vs ILOAD at VIN = 3.6V
1000 TA = -40C TA = 0C TA = 40C TA = 80C TA = 120C
QUIESCENT CURRENT (A)
FORWARD VOLTAGE (V)
0.3
100
RESISTANCE ()
10 0 0.5 1.0 1.5 2.0 LOAD CURRENT (A) 2.5 3.0
4411 G01
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VFWD vs ILOAD at VIN = 3.6V
0.5 TA = -40C TA = 0C TA = 40C TA = 80C TA = 120C 0.30 0.25 0.20 0.15 0.10 0.05 0
RFWD and RON vs ILOAD at VIN = 3.6V
TA = -40C TA = 0C TA = 40C TA = 80C TA = 120C
0.4
0.2
0.1
0 0 0.5 1.0 1.5 2.0 LOAD CURRENT (A) 2.5 3.0
4411 G02
0
0.5
1.0 1.5 LOAD CURRENT (A)
2.0
4411 G03
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LTC4411 TYPICAL PERFOR A CE CHARACTERISTICS
RFWD vs VSUPPLY
0.150 TA = -40C TA = 0C TA = 40C 0.20 TA = 80C TA = 120C 0.15
IQROUT CURRENT (A)
0.125
RFWD ()
RFWD ()
0.100
0.075
0.050
2.5
3.0
3.5 4.0 4.5 SUPPLY VOLTAGE (V)
ILEAK vs VREVERSE, VIN = 0V
10 TA = 60C TA = 80C TA = 100C TA = 120C VCTRL 500mV/DIV VSTAT 2V/DIV
LEAKAGE CURRENT (A)
1
100n
10n
0
1
2 3 4 REVERSE VOLTAGE (V)
PI FU CTIO S
IN (Pin 1): Ideal Diode Anode and Positive Power Supply for LTC4411. When operating LTC4411 as a switch it must be bypassed with a low ESR ceramic capacitor of 1F. X5R and X7R dielectrics are preferred for their superior voltage and temperature characteristics. GND (Pin 2): Power and Signal Ground for the IC. CTL (Pin 3): Controlled Shutdown Pin. Weak (3A) PullDown. Pull this pin high to shut down the IC. Tie to GND to enable. Can be left floating when not in use. STAT (Pin 4): Status Condition Indicator. This pin indicates the conducting status of the LTC4411. If the part is forward biased (VIN > VOUT + VFWD) this pin will be Hi-Z. If the part is reverse biased (VOUT > VIN + VRTO), then this pin will pull down 10A through an open-drain. When terminated to a high voltage through a 470k resistor, a high voltage indicates diode conducting. May be left floating or grounded when not in use. OUT (Pin 5): Ideal Diode Cathode and Output of the LTC4411. Bypass OUT with a nominal 1m ESR capacitor of at least 4.7F. The LTC4411 is stable with ESRs down to 0.2m. However stability improves with higher ESRs.
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5.0 5
RFWD vs Temperature at VIN = 3.6V
100
IQROUT vs VREVERSE at VIN = 0V
10
0.10
1
0.05
5.5
4411 G04
0 -40 -20
0
20 40 60 80 TEMPERATURE (C)
100n 100 120
4411 G05
TA = -40C TA = 0C TA = 40C TA = 80C TA = 120C 0 1 2 3 4 REVERSE VOLTAGE (V) 5 6
4411 G06
CTL Turn-On
VCTRL 500mV/DIV VSTAT 2V/DIV VOUT 2V/DIV IOUT 50mA/DIV
CTL Turn-Off
VOUT 2V/DIV IOUT 500mA/DIV 200s/DIV
4411 G08
20s/DIV
4411 G09
6
4411 G07
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LTC4411
BLOCK DIAGRA W
+ -
5 OUT
IN
1
-+
P1 VGATE
GND
2 SHDB
VREF OFF CTL 3 3A VB
Figure 2. Detailed Block Diagram
OPERATIO
LOAD CURRENT (A)
The LTC4411 operation is described with the aid of Figure 3. Forward regulation for the LTC4411 has three operation modes depending on the magnitude of the load current. For small load currents, the LTC4411 will provide a constant voltage drop; this operating mode is referred to as "constant VON" regulation. As the current exceeds IFWD the voltage drop will increase linearly with the current with a slope of 1/RON; this operating mode is referred to as "constant RON" regulation. As the current increases further, exceeding IMAX, the forward voltage drop will increase rapidly; this operating mode is referred to as "constant ION" regulation. The characteristics for the following parameters: RFWD, RON, VFWD, IFWD, and IMAX are specified with the aid of Figure 3. Operation begins when the power source at IN rises above the UVLO voltage of 2.4V (typ) and the CTL (control) pin is low. If only the voltage at the IN pin is present, the power source to LTC4411 (VDD) will be supplied from the IN pin. The amplifier (A) will deliver a voltage proportional to the difference between VIN and VOUT to the gate (VGATE) of the internal P-channel MOSFET (P1), driving this gate voltage below VIN. This will turn on P1. As P1 conducts, VOUT will be pulled up towards VIN. The LTC4411 will then control VGATE to maintain a low forward voltage drop. The system is now in forward regulation and the load at OUT will be
- +
- +
OVERTEMP
A UVLO OUTMAX VB 10A
4 STAT
4411 F02
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powered from the supply at IN. As the load current varies, VGATE will be controlled to maintain a low forward voltage drop. If the load current exceeds P1's ability to deliver the current, as VGATE approaches GND, the P1 will behave as a fixed resistor, with resistance RON, whereby the forward voltage will increase with increased load current. As ILOAD increases further (ILOAD > IMAX), the LTC4411 will regulate the load current as described below. During the forward regulation mode of operation the STAT pin will be an open circuit.
3.0 IOC IMAX 2.0 LTC4411 IFWD 1.5 1.0 0.5 0 SLOPE 1/RFWD SLOPE 1/RON 2.5 TA = 40C SCHOTTKY DIODE 1.0
4411 F03
0 VFWD
0.25 0.5 0.75 FORWARD VOLTAGE (V)
Figure 3. LTC4411 vs Schottky Diode Forward Conduction Characteristics
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LTC4411
OPERATIO
When the load current exceeds IMAX, an over current condition is detected and the LTC4411 will limit the output current. This will cause the output voltage to drop as the load current exceeds the amount of current that the LTC4411 can supply. This condition will increase the power consumption within the LTC4411. When an alternate power source is connected to the output, the LTC4411 will sense the increased voltage at OUT, and the amplifier (A) will increase the voltage at VGATE. When VOUT is higher than VIN + VRTO, the internal power source for the LTC4411 (VDD) will be diverted to source current from the OUT pin. At the same time VGATE will be pulled to VDD, which will turn off P1. The system is now in the reverse turn-off mode. Power to the load is being delivered from an alternate supply, and only a small
NORMAL OPERATION REVERSE BIASED ISTAT = 10A DIODE OFF VCTL > VIH VIN - VOUT < VFWD VIN - VOUT > VFWD ISTAT = 0 CONSTANT VON DIODE ON REGULATION VCTL < VIL CONTROL SHUTDOWN ISTAT = 10A DIODE OFF
APPLICATIO S I FOR ATIO
INTRODUCTION
The LTC4411 is intended for power control applications that include low loss diode ORing, fully automatic switchover from a primary to an auxiliary source of power, microcontroller controlled switchover from a primary to an auxiliary source of power, load sharing between two or more batteries, charging of multiple batteries from a single charger and high side power switching.
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current is drawn from IN to sense the potential VIN. During reverse turn-off mode the STAT pin will sink 10A to indicate that the diode is not conducting. When the CTL input is asserted (high), P1 will have its gate voltage pulled high, and the STAT pin will sink 10A. A 3A pull-down current on the CTL pin will ensure a low level at this input if it is left open circuited. The overtemperature condition is detected when the internal die temperature increases beyond 150C. The overtemperature condition will cause the gate amplifier (A) as well as P1 to be shut off. When the internal die temperature cools to below 140C, the amplifier will turn on and revert to normal operation. Note that prolonged operation under overtemperature conditions will degrade reliability.
VDD < 2.3 IOUT > IFWD IOUT < IFWD VDD > 2.4 UNDER VOLTAGE LOCK-OUT ISTAT = 0 DIODE OFF ISTAT = 0 CONSTANT RON DIODE ON REGULATION TJ > 150C IOUT > IMAX IOUT < IMAX ISTAT = 0 CONSTANT ION DIODE ON REGULATION TJ < 140C WHERE: VDD = MAX {VIN, VOUT} VIL = VTH - VHYST/2 VIH = VTH + VHYST/2 ISTAT = 0 OVER DIODE OFF TEMPERATURE SHUTDOWN
4411 F04
Figure 4. State Transition Diagram
Automatic PowerPath Control Figure 1 illustrates an application circuit for automatic switchover of a load between a battery and a wall adapter or other power input. With initial application of the battery, the load will be charged up as the LTC4411 turns on. The LTC4411 will control the gate voltage of its internal MOSFET to reduce the MOSFET's voltage drop to a low forward voltage (VFWD). The system is now in the forward regula4411fa
LTC4411
APPLICATIO S I FOR ATIO
tion mode, the forward voltage will be kept low by controlling the gate voltage of the internal MOSFET to react to changes in load current. Should the wall adapter input be applied, the Schottky diode will pull up the output voltage, connected to the load, above the battery voltage. The LTC4411 will sense that the output voltage is higher than the battery voltage and will turn off the internal MOSFET. The STAT pin will then sink current indicating an auxiliary input is connected. The battery is now supplying no load current and all load current flows through the Schottky diode. Microcontrolled PowerPath Monitoring and Control Figure 6 illustrates an application circuit for microcontroller monitoring and control of two power sources. The microcontroller's analog inputs, perhaps with the aid of a resistor voltage divider, monitors each supply input and commands the LTC4411 through the CTL input. Back-toback MOSFETs are used so that the parasitic drain-source diode will not power the load when the MOSFET is turned off (dual MOSFETs in one package are commercially available).
AUXILIARY P-CHANNEL MOSFETS AUXILIARY POWER SOURCE
R1 470k
CIN 1F BAT2
MICROCONTROLLER
PRIMARY POWER SOURCE
1 C1 10F 2 3
IN
5 C2 4.7F 4 STAT
4411 F05
OUT LTC4411 GND CTL
LOAD
CIN: C0805C105K8PAC COUT: C1206C475K8PAC
STATUS
C1: C0805C106K8PAC C2: C1206C475K8PAC
Figure 5. Automatic Switchover of Load Between a Primary and an Auxiliary Power Source with External Dual P-Channel MOSFETs
Load Sharing Figure 6 illustrates an application circuit for dual battery load sharing with automatic switchover of load from batteries to wall adapter. Whichever battery is capable of supplying the higher voltage will provide the load current until it is discharged to the voltage of the other battery. The load will then be shared between the two batteries according to the capacity of each battery. The higher capacity battery will provide proportionally higher current to the load. When a wall adapter input is applied, both LTC4411s
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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turn off and no load current will be drawn from the batteries. The STAT pins provide information as to which input is supplying the load current. This concept can be expanded to more power inputs. Multiple Battery Charging Figure 7 illustrates an application circuit for automatic dual battery charging from a single charger. Whichever battery has the lower voltage will receive the charging current until both battery voltages are equal, then both will be charged. When both are charging simultaneously, the higher capacity battery will get proportionally higher current from the charger. For Li-Ion batteries, both batteries will achieve the float voltage minus the forward regulation voltage of 40mV. This concept can apply to more than two batteries. The STAT pin provides information as to which batteries are being charged. For intelligent control, the CTL pin input can be used with a microcontroller as shown in Figure 5.
WALL ADAPTER INPUT CIN 1F BAT1 1 2 3 5 VCC 470k 4 COUT 4.7F TO LOAD OUT LTC4411 GND IN CTL STAT STATUS IS HIGH WHEN BAT1 IS SUPPLYING LOAD CURRENT WHEN BOTH STATUS LINES ARE HIGH, THEN BOTH BATTERIES ARE SUPPLYING LOAD CURRENT. WHEN BOTH STATUS LINES ARE LOW, THEN WALL ADAPTER IS PRESENT AND SUPPLYING FULL LOAD CURRENT STATUS IS HIGH WHEN BAT2 IS SUPPLYING LOAD CURRENT
4411 F06
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1 2 3
IN
OUT LTC4411 GND CTL STAT
VCC 470k
Figure 6. Dual Battery Load Sharing with Automatic Switchover of Load from Batteries to Wall Adapter
BATTERY CHARGER INPUT 1 OUT LTC4411 2 GND IN 3 CTL STAT 5 VCC BAT1 470k 4 STATUS IS HIGH WHEN BAT1 IS CHARGING TO LOAD OR PowerPath CONTROLLER 1 2 3 IN OUT LTC4411 GND CTL STAT BAT2 VCC 470k STATUS IS HIGH WHEN BAT2 IS CHARGING
4411 F07
TO LOAD OR PowerPath CONTROLLER
Figure 7. Automatic Dual Battery Charging from a Single Charging Source
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LTC4411
APPLICATIO S I FOR ATIO
High Side Power Switch Figure 8 illustrates an application circuit for a logic controlled high side power switch. When the CTL pin is a logical low, the LTC4411 will turn on, supplying current to the load. When the CTL pin is a logical high, the LTC4411 will turn off and deny power to the load. If the load is powered from another (higher voltage) source, the supply connected to VIN remains disconnected from the load.
PACKAGE DESCRIPTIO
0.62 MAX
(Reference LTC DWG # 05-08-1635)
0.95 REF 2.90 BSC (NOTE 4)
1.22 REF
3.85 MAX 2.62 REF
RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR
0.20 BSC 1.00 MAX DATUM `A'
0.30 - 0.50 REF 0.09 - 0.20 (NOTE 3) 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. JEDEC PACKAGE REFERENCE IS MO-193
RELATED PARTS
PART NUMBER LTC1558/LTC1559 LTC1998 LTC4054 LTC4350 LTC4412/LTC4412HV DESCRIPTION Backup Battery Controller with Programmable Output 2.5A, 1% Accurate Programmable Battery Detector 800mA Standalone Linear Li-Ion Battery Charger with Thermal Regulation in ThinSOT Hot Swappable Load Share Controller PowerPath Controller in ThinSOT COMMENTS Adjustable Backup Voltage from 1.2V NiCd Button Cell, Includes Boost Converter Adjustable Trip Voltage/Hysteresis, ThinSOT No External MOSFET, Sense Resistor or Blocking Diode Required, Charge Current Monitor for Gas Gauging, C/10 Charge Termination Allows N + 1 Redundant Supply, Equally Loads Multiple Power Supplies Connected in Parallel More Efficient than Diode OR'ing, Automatic Switching Between DC Sources, Simplified Load Sharing, 3V VIN 36V (LTC4412HV)
4411fa LT/LT 0305 REV A * PRINTED IN USA
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Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 FAX: (408) 434-0507
www.linear.com
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SUPPLY INPUT CIN 1F LOGIC INPUT 1 OUT LTC4411 2 GND 3 CTL 4 STAT
4411 F08
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IN
5
TO COUT LOAD 4.7F
CIN: C0805C105K8PAC COUT: C1206C475K8PAC
Figure 8. Logic Controlled High Side Power Switch
S5 Package 5-Lead Plastic TSOT-23
1.4 MIN
2.80 BSC
1.50 - 1.75 (NOTE 4)
PIN ONE 0.30 - 0.45 TYP 5 PLCS (NOTE 3)
0.95 BSC
0.80 - 0.90 0.01 - 0.10
1.90 BSC
S5 TSOT-23 0302
(c) LINEAR TECHNOLOGY CORPORATION 2003

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