LTC4062
1
4062fb
■
Charge Current Programmable Up to 1A
■
Charges Single-Cell Li-Ion Batteries Directly from
USB Port
■
Preset Float Voltage with
±
0.35% Accuracy
■
Micropower Comparator for Battery Monitoring
■
Thermal Regulation Maximizes Charge Rate
Without Risk of Overheating
■
Programmable Charge Current Detection/
Termination
■
Programmable Charge Termination Timer
■
Smart Pulsing Error Feature
■
SmartStart
TM
Prolongs Battery Life
■
20µA Charger Quiescent Current in Shutdown
■
Available in a Low Profile (0.75mm) 10-Lead
(3mm × 3mm) DFN Package
TYPICAL APPLICATIO
U
FEATURES
DESCRIPTIO
U
Standalone Linear Li-Ion
Battery Charger with
Micropower Comparator
APPLICATIO S
U
■
Handheld Computers
■
Portable MP3 Players
■
Digital Cameras
Complete Charge Cycle (1100mAh Battery)
The LTC
®
4062 is a full-featured, flexible, standalone linear
charger for single-cell Lithium-Ion batteries. It is capable
of operating within USB power specifications.
Both programmable time and programmable current based
termination schemes are available. Furthermore, the CHRG
open-drain status pin can be programmed to indicate the
battery charge state according to the needs of the applica-
tion. A precise low power comparator is available even
with no power applied as long as battery voltage is higher
than 2.5V. Additional safety features designed to maxi-
mize battery lifetime and reliability include the SmartStart
charging algorithm.
No external sense resistor or external blocking diode is
required for charging due to the internal MOSFET architec-
ture. Internal thermal feedback regulates the charge cur-
rent to maintain a constant die temperature during high
power operation or high ambient temperature conditions.
The charge current is programmed with an external resis-
tor. With power applied, the LTC4062 can be put into
shutdown mode to reduce the supply current to 20µA and
the battery drain current to less than 5µA. Without power
applied, the internal low power comparator can work
sinking only 10µA from the battery.
Other features include smart recharge, USB C/5 current
programming input and undervoltage lockout.
TIME (HOURS)
0 0.5 1.5 2.5 3.0
CHARGE CURRENT (mA)
BATTERY VOLTAGE (V)
2.0
900
800
700
600
500
400
300
200
100
0
4.3
4.2
4.1
4.0
3.9
3.8
3.7
3.6
3.5
3.4
4062 TA01b
1.0
BATTERY
CURRENT
BATTERY
VOLTAGE
V
CC
= 5V
T
A
= 25°C
800mA Single-Cell Li-Ion Battery Charger
(C/10 Termination)
+
TIMER
PROG
EN
C/5
I
OUT
BAT
VIN
4.3V TO 8V
IN+
DET
LTC4062
GND
619Ω
100k
715k
347k
800mA
1µF
4062 TA01
SINGLE-CELL
Li-Ion BATTERY
VCC BAT > 3V BAT < 3V
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
SmartStart is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 6522118.
LTC4062
2
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ABSOLUTE AXI U RATI GS
W
WW
U
PACKAGE/ORDER I FOR ATIO
UUW
(Note 1)
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise noted.
Input Supply Voltage (V
CC
) ........................ –0.3V to 10V
EN, OUT, CHRG, IN
+
, PROG, C/5, BAT ....... –0.3V to 10V
TIMER, I
DET
..................................... –0.3V to V
CC
+0.3V
BAT Short-Circuit Duration ...........................Continuous
V
CC
Pin Current ......................................................... 1A
BAT Pin Current ......................................................... 1A
Maximum Junction Temperature .......................... 125°C
Operating Temperature Range (Note 2) ... –40°C to 85°C
Storage Temperature Range .................. –65°C to 125°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
CC
Input Supply Voltage ●4.3 8 V
I
CC
Input Supply Current Charge Mode (Note 4), R
PROG
= 10k ●240 500 µA
Standby Mode, Charge Terminated ●130 300 µA
Shutdown (EN = 5V, V
CC
< V
BAT
or V
CC
< V
UV
)●20 50 µA
V
FLOAT
V
BAT
Regulated Output Voltage 4.185 4.2 4.215 V
0 < T
A
< 85°C 4.175 4.2 4.225 V
I
BAT
BAT Pin Current R
PROG
= 10k, Constant Current Mode ●93 100 107 mA
R
PROG
= 1.25k, Constant Current Mode ●760 800 840 mA
Standby Mode, Charge Terminated, V
BAT
= 4.2V ●–3.5 –7 µA
Shutdown Mode, V
BAT
= 4.2V ●±1 ±5µA
V
PROG
PROG Pin Voltage R
PROG
= 10k, Constant Current Mode 0.97 1 1.03 V
R
PROG
= 1.25k, Constant Current Mode 0.97 1 1.03 V
V
OUT
OUT Output Low Voltage I
OUT
= 5mA 0.10 0.25 V
I
OUT
= 5mA, V
CC
= 0V, V
BAT
= 2.55V 0.16 0.26 V
V
CHRG
CHRG Output Low Voltage I
CHRG
= 5mA 0.1 0.25 V
I
TRIKL
Trickle Charge Current V
BAT
< V
TRIKL
, R
PROG
= 10k 6 10 14 mA
V
BAT
< V
TRIKL
, R
PROG
= 1.25k 60 80 100 mA
V
TRIKL
Trickle Charge Threshold Voltage V
BAT
Rising 2.8 2.9 3 V
Hysteresis 100 mV
V
UV
V
CC
Undervoltage Lockout From Low to High 3.7 3.8 3.9 V
Voltage Hysteresis 200 V
V
ASD
V
CC
– V
BAT
Lockout Threshold V
CC
from Low to High, V
BAT
= 4.3V 145 190 230 mV
Voltage V
CC
from High to Low, V
BAT
= 4.3V 10 45 75 mV
R
EN
EN Pin Pull-Down Resistor ●2 3.4 5 MΩ
TOP VIEW
10
9
6
7
811
4
5
3
2
1V
CC
PROG
I
DET
EN
C/5
BAT
IN+
TIMER
OUT
CHRG
DD PACKAGE
10-LEAD (3mm × 3mm) PLASTIC DFN
T
JMAX
= 125°C, θ
JA
= 40°C/W (NOTE 3)
EXPOSED PAD IS GROUND (PIN 11)
MUST BE SOLDERED TO PCB
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ORDER PART NUMBER DD PART MARKING
LTC4062EDD LBJT
LTC4062
3
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ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise noted.
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 LTC4062 is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 3: Failure to correctly solder the exposed pad of the package to the
PC board will result in a thermal resistance much higher than 40°C/W.
Note 4: Supply current includes PROG pin current and I
DET
pin current
(approximately 100µA each) but does not include any current delivered to
the battery through the BAT pin (approximately 100mA).
Note 5: This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions.
Overtemperature protection will become active at a junction temperature
greater than the maximum operating temperature. Continuous operation
above the specified maximum operating junction temperature may impair
device reliability.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
EN
EN Input Threshold Voltage EN Rising, 4.3V < V
CC
< 8V 0.4 0.7 1 V
Hysteresis 70 mV
V
CT
Charge Termination Mode Threshold V
TIMER
from High to Low 0.4 0.7 1 V
Voltage Hysteresis 50 mV
V
UT
User Termination Mode Threshold V
TIMER
from Low to High 3.9 4.2 V
Voltage Hysteresis 50 mV
I
DETECT
Charge Current Detection Threshold R
DET
= 1k, 0 ≤ T
A
≤ 85°C 90 100 110 mA
R
DET
= 2k, 0 ≤ T
A
≤ 85°C455055mA
R
DET
= 10k, 0 ≤ T
A
≤ 85°C81012mA
R
DET
= 20k, 0 ≤ T
A
≤ 85°C 3.8 5 6.2 mA
∆V
RECHRG
Recharge Threshold Voltage V
FLOAT
–
V
RECHRG
, 0 ≤ T
A
≤ 85°C 65 100 135 mV
t
SS
Soft-Start Time I
BAT
from 0 to I
CHG
100 µs
t
TERM
Termination Comparator Filter Time Current Termination Mode 0.8 1.5 2.5 ms
t
RECHRG
Recharge Comparator Filter Time 3 7 14 ms
t
TIMER
Charge Cycle Time C
TIMER
= 0.1µF 2.55 3 3.45 hr
R
C/5
C/5 Pin Pull-Down Resistor ●2 3.4 5 MΩ
V
C/5
C/5 Input Threshold Voltage C/5 Rising, 4.3V < V
CC
< 8V 0.4 0.7 1 V
Hysteresis 70 mV
T
LIM
Junction Temperature in Constant 105 °C
Temperature Mode
R
ON
Power FET “ON” Resistance V
BAT
= 3.85V, I
CC
= 175mA, R
PROG
= 2k 375 mΩ
(Between V
CC
and BAT)
Comparator
V
IN
+IN
+
Pin Threshold Voltage V
IN
+
Falling ●0.988 1 1.012 V
Hysteresis 50 mV
V
BAT-MIN
Minimum V
BAT
Supply Voltage for the V
CC
= 0V, V
BAT
Falling 2.4 2.5 2.6 V
Low Power Comparator Hysteresis 100 mV
I
BAT
Supply Current for the Low Power V
CC
= 0V, V
BAT
= 2.5V 7 9 13 µA
Comparator
LTC4062
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TYPICAL PERFOR A CE CHARACTERISTICS
UW
Battery Regulated Output (Float)
Voltage vs Charge Current
PROG Pin Voltage vs Temperature
(Constant-Current Mode)
Charge Current vs PROG
Pin Voltage
PROG Pin Voltage vs VCC
(Constant-Current Mode)
Trickle Charge Current vs
Temperature Charge Current vs Battery Voltage
Trickle Charge Threshold Voltage
vs Temperature
Battery Regulated Output (Float)
Voltage vs Temperature
Battery Regulated Output (Float)
Voltage vs Supply Voltage
CHARGE CURRENT (mA)
0600 1000
4062 G01
200 400 800
4.26
4.24
4.22
4.20
4.18
VFLOAT (V)
4.16
4.14
4.12
4.10
TEMPERATURE (°C)
–50
VFLOAT (V)
4.215
4.210
4.205
4.200
4.195
4.190
4.185 –25 02550
4062 G02
75 100
–50 –25 0 25 50 75 100
–50 –25 0 25 50 75 100
TEMPERATURE (°C)
VPROG (V)
4062 G05
1.006
1.004
1.002
1.000
0.998
0.996
0.994
VPROG (V)
0
IBAT (mA)
1200
1000
800
600
400
200
00.2 0.4 0.6 0.8
4062 G04
1.0 1.2
TEMPERATURE (°C)
ITRICKLE (mA)
84
82
80
78
76
4062 G07
–50 –25 0 25 50 75 100
TEMPERATURE (°C)
VTRICKLE (V)
2.96
2.94
2.92
2.90
2.88
2.86
2.84
4062 G08
VBAT (V)
3.0
IBAT (mA)
550
450
350
250
150
50 3.8
4062 G09
3.2 3.4 3.6 4.0
VCC = 5V
RPROG = 1k
VCC = 5V
RPROG = 10k
RPROG = 10k
C/5 = VCC
VCC = 5V
VBAT = 2.5V
RPROG = 1.25k
VCC = 5V
RPROG = 1.25k
VCC = 5V
RPROG = 1k
C/5 = 5V
VTIMER = 5V
VCC = 5V
RPROG = 2k
VCC = 4.3V
VCC = 8V
C/5 = 5V
C/5 = 0V
4062 G03
VCC (V)
4.0
VFLOAT (V)
8.0
5.0 6.0 7.0
4.5 5.5 6.5 7.5
4.26
4.24
4.22
4.20
4.18
4.16
4.14
4.12
4.10
RPROG = 1k
TA = 25°C
IBAT = 10mA
4062 G06
VCC (V)
4.0
VPROG (V)
8.0
5.0 6.0 7.0
1.006
1.004
1.002
1.000
0.998
0.996
0.994 4.5 5.5 6.5 7.5
VCC = 5V
VBAT = 4V
RPROG = 10k
C/5 = 5V
TA = 25°C unless otherwise noted.
LTC4062
5
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Internal Charge Timer vs
Temperature Charge Current vs Supply Voltage
Charge Current vs Ambient
Temperature with Thermal
Regulation
Recharge Threshold Voltage vs
Temperature
Power FET “ON” Resistance vs
Temperature
Charge Current vs Battery Voltage
Undervoltage Lockout Voltage vs
Temperature
EN Pin Pulldown Resistance vs
Temperature
C/5 Pin Pulldown Resistance vs
Temperature
TEMPERATURE (°C)
–50 –25
0
I
BAT
(mA)
400
1000
050 75
4062 G13 4062 G14
200
800
600
25 100 125
R
PROG
= 1.25k
ONSET OF THERMAL
REGULATION
R
PROG
= 2k
V
CC
(V)
4.0
I
BAT
(mA)
8.0
5.0 6.0 7.0
104
102
100
98
96 4.5 5.5 6.5 7.5
TEMPERATURE (°C)
–50
V
RECHARGE
(V)
4.16
4.14
4.12
4.10
4.08
4.06
4.04 –25 02550
4062 G15
75 100
TEMPERATURE (°C)
–50
500
R
DS(ON)
(mΩ)
450
400
350
300
250
–25 02550
4062 G16
75 100
V
CC
= 4V
I
BAT
= 200mA
V
CC
= 8V
V
CC
= 4.3V
V
CC
= 5V
V
BAT
= 4V
C/5 = 5V
R
PROG
= 10k
–50 –25 0 25 50 75 100
TEMPERATURE (°C)
t
TIMER
(MINUTES)
195
190
185
180
175
170
165
4062 G10
C
TIMER
= 0.1µF
V
CC
= 4.3V
V
CC
= 8V
4062 G17
4062 G18
TEMPERATURE (°C)
–50 25 75
–25 0 50 100
V
UV
(V)
3.900
3.875
3.850
3.825
3.800
3.775
3.750
3.725
3.700
V
BAT
(V)
0
I
BAT
(mA)
3.0
900
800
700
600
500
400
300
200
100
0
0.5 4.5
1.0 1.5 2.0 2.5 3.5 4.0
V
CC
= 5V
C/5 = 5V
R
PROG
= 1.25k
θ
JA
= 40°C/W
V
CC
= 5V
V
BAT
= 4V
θ
JA
= 40°C/W
4062 G19
TEMPERATURE (°C)
–50 25 75
–25 0 50 100
5.0
4.5
4.0
3.5
3.0
2.5
2.0
R
EN
(MΩ)
4062 G20
TEMPERATURE (°C)
–50 25 75
–25 0 50 100
5.0
4.5
4.0
3.5
3.0
2.5
2.0
R
C/5
(MΩ)
TYPICAL PERFOR A CE CHARACTERISTICS
UW
TA = 25°C unless otherwise noted.
LTC4062
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EN Pin Threshold Voltage
(On-to-Off) vs Temperature
Shutdown Supply Current vs
Temperature and VCC
C/5 Pin Threshold Voltage
(High-to-Low) vs Temperature
CHRG Pin Output Low Voltage vs
Temperature
OUT Pin Output Low Voltage vs
Temperature CHRG Pin I-V Curve
OUT Pin I-V Curve
4062 G22
4062 G25
4062 G26
TEMPERATURE (°C)
–50 25 75
–25 0 50 100
VC/5 (mV)
900
850
800
750
700
650
600
TEMPERATURE (°C)
–50
VCHRG (V)
0.6
0.5
0.4
0.3
0.2
0.1
025 75
–25 0 50 100
TEMPERATURE (°C)
–50
VOUT (V)
0.6
0.5
0.4
0.3
0.2
0.1
025 75
–25 0 50 100
VCC = 5V
VCC = 5V
IOUT = 5mA
VCC = 5V
ICHRG = 5mA
TEMPERATURE (°C)
–50
VEN (mV)
900
850
800
750
700
650
600 –25 02550
4062 G21
75 100
TEMPERATURE (°C)
–50
ICC (µA)
70
60
50
40
30
20
10 –25 02550
4062 G23
75 100
VCC = 5V EN = VCC
VCC = 4.3V
VCC = 8V
VCC = 5V
IOUT (mA)
4062 G24
VOUT (V)
04
123
160
140
120
100
80
60
40
20
0
VCC = 5V
VBAT = 4V TA = –40°C
TA = 25°C
TA = 90°C
VCHRG (V)
0
ICHRG (mA)
160
140
120
100
80
60
40
20
0123 4
4062 G27
VCC = 5V
VBAT = 4V
TA = 25°C
TA = –40°C
TA = 90°C
IN+ ≥ 1.05V
TYPICAL PERFOR A CE CHARACTERISTICS
UW
TA = 25°C unless otherwise noted.
LTC4062
7
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UU
U
PI FU CTIO S
BAT (Pin 1): Charge Current Output. This pin provides
charge current to the battery and regulates the final float
voltage to 4.2V.
IN
+
(Pin 2): Positive Input of the Micropower Comparator.
The negative input is tied internally to a precise bandgap
voltage reference of 1V. There is approximately 50mV of
hysteresis associated with the input comparator threshold
(rising edge).
TIMER (Pin 3): Timer Program and Termination Select
Pin. This pin selects which method is used to terminate the
charge cycle. Connecting a capacitor, C
TIMER
, to ground
selects charge time termination. The charge time is set by
the following formula:
TIME HOURS HOURS C
For
CF
TIME HOURS
HOURS
TIMER
TIMER
()()•
.
.• ()
()
=µ
=µ
301
01 3
Connecting the TIMER pin to ground selects charge cur-
rent termination, while connecting the pin to V
CC
selects
user termination. See Applications Information for more
information on current and user termination.
OUT (Pin 4): Low Power Comparator Open-Drain Output.
This comparator output pin has two states; pull-down and
high impedance. This output can be used as a logic
interface or as an LED driver. In the pull-down state, an
NMOS transistor capable of sinking 10mA pulls down on
the OUT pin. The state of this pin is dependent on the value
of IN
+
. When IN
+
is greater than 1V the output pin is in pull-
down state, if IN
+
is less than 1V the output pin is in high
impedance state. See Applications Information.
CHRG (Pin 5): Open-Drain Charge Status Output. The
charge status indicator pin has three states: pull-down,
pulse at 6Hz and high impedance. This output can be used
as a logic interface or as a LED driver. In the pull-down
state, an NMOS transistor capable of sinking 10mA pulls
down on the CHRG pin. The state of this pin depends on the
value of I
DETECT
as well as the termination method being
used. See Applications Information.
C/5 (Pin 6): C/5 Enable Input. Used to control the amount
of current drawn by the charger when powered from a USB
port. A logic high on the C/5 pin sets the current limit to
100% of the current programmed by the PROG pin. A logic
low on the C/5 pin sets the current limit to 20% of the current
programmed by the PROG pin. An internal 3MΩ pull-down
resistor defaults the C/5 pin to its low current state.
EN (Pin 7): Charger Enable Input. A logic high on the EN
pin places the charger into shutdown mode, where the
input quiescent current is less than 50µA. A logic low on
this pin enables charging. An internal 3MΩ pull-down
resistor to ground defaults the charger to its enabled state.
I
DET
(Pin 8): Current Detection Threshold Program Pin.
The current detection threshold, I
DETECT
, is set by con-
necting a resistor, R
DETECT
, to ground. I
DETECT
is set by the
following formula:
IR
RIV
Ror
RV
I
DETECT PROG
DET CHG DET
DET DETECT
==
=
10
100
100
•
The CHRG pin becomes high impedance when the charge
current drops below I
DETECT
. I
DETECT
can be set to 1/10th
the programmed charge current by connecting I
DET
di-
rectly to PROG. If the I
DET
pin is not connected, the CHRG
output remains in its pull-down state until the charge time
elapses and terminates the charge cycle. See Applications
Information.
This pin is clamped to approximately 2.4V. Driving this pin
to voltages beyond the clamp voltage should be avoided.
PROG (Pin 9): Charge Current Program and Charge Cur-
rent Monitor. The charge current is set by connecting a
resistor, R
PROG
, to ground. When charging in constant
current mode, this pin servos to 1V. The voltage on this pin
can be used to measure the charge current using the
following formula:
IV
R
BAT PROG
PROG
=•1000
LTC4062
8
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UU
U
PI FU CTIO S
–
+
–
+
–+
11983
CA
MA
1×1×1000×
1.2V
2.9V
PROGIDET
RDET
CTIMER RPROG
0.1V TO BAT
0.2V
1V
0.1V
–+–+
C3C2
LOGIC
TA
TDIE
105°C
SHDN
4062 BD
GND
–+
VA
BAT
VCC
1
10
TERM
RECHRG
4.1V
1V
TO BAT
EN
SEL
TIMER
COUNTER
OSCILLATOR
IN+
OUT
CHRG
C/5
EN
LOGIC
C/5
C/5
STOP
3M
3M
5
6
7
–
+
–
+
C1
4
2
C4
BLOCK DIAGRA
W
V
CC
(Pin 10): Positive Input Supply Voltage. Provides
power to the battery charger. This pin should be bypassed
with a 1µF capacitor.
GND (Exposed Pad) (Pin 11): Ground. This pin is the back
of the exposed metal pad package and must be soldered
to the PCB copper for minimal thermal resistance.
LTC4062
9
4062fb
OPERATIO
U
The LTC4062 is designed to charge single-cell lithium-ion
batteries. Using the constant current/constant voltage
algorithm, the charger can deliver up to 1A of charge
current with a final float voltage accuracy of ±0.35%. The
LTC4062 includes an internal P-channel power MOSFET
and thermal regulation circuitry. No blocking diode or
external sense resistor is required; thus, the basic charger
circuit requires only two external components.
Normal Operation
The charge cycle begins when the voltage at the V
CC
pin
rises above the UVLO level and a discharged battery is
connected to BAT. If the BAT pin voltage is below 2.9V, the
charger enters trickle charge mode. In this mode, the
LTC4062 supplies 1/10th of the programmed charge
current in order to bring the battery voltage up to a safe
level for full current charging.
Once the BAT pin voltage rises above 2.9V, the charger
enters constant current mode, where the programmed
charge current is supplied to the battery. When the BAT pin
approaches the final float voltage (4.2V), the LTC4062
enters constant voltage mode and the charge current
decreases as the battery becomes fully charged.
The LTC4062 offers several methods with which to termi-
nate a charge cycle. Connecting an external capacitor to
the TIMER pin activates an internal timer that stops the
charge cycle after the programmed time period has elapsed.
Grounding the TIMER pin and connecting a resistor to the
I
DET
pin causes the charge cycle to terminate once the
charge current falls below a set threshold when the charger
is in constant voltage mode. Connecting the TIMER pin to
V
CC
disables internal termination, allowing external charge
user termination through the EN input. See Applications
Information for more information on charge termination
methods.
Programming Charge Current
The charge current is programmed using a single resistor
from the PROG pin to ground. When the charger is in the
constant current mode, the voltage on the PROG pin is 1V.
The battery charge current is 1000 times the current out of
the PROG pin. The program resistor and the charge
current are calculated by the following equations:
RV
IIV
R
PROG CHG CHG PROG
==
1000 1000
,
The charge current out of the BAT pin can be determined
at any time by monitoring the PROG pin voltage and
applying the following equation:
IV
R
BAT PROG
PROG
=•1000
SmartStart
When the LTC4062 is initially powered on or brought out
of shutdown mode, the charger checks the battery voltage.
If the BAT pin is below the recharge threshold of 4.1V
(which corresponds to approximately 80-90% battery
capacity), the LTC4062 enters charge mode and begins a
full charge cycle. If the BAT pin is above 4.1V, the LTC4062
enters standby mode and does not begin charging. This
feature reduces the number of unnecessary charge cycles,
prolonging battery life.
Automatic Recharge
When the charger is in standby mode, the LTC4062
continuously monitors the voltage on the BAT pin. When
the BAT pin voltage drops below 4.1V, the charge cycle is
automatically restarted and the internal timer is reset to
50% of the programmed charge time (if time termination
LTC4062
10
4062fb
OPERATIO
U
is being used). This feature eliminates the need for peri-
odic charge cycle initiations and ensures that the battery
is always fully charged. Automatic recharge is disabled in
user termination mode.
Thermal Regulation
An internal thermal feedback loop reduces the programmed
charge current if the die temperature attempts to rise
above a preset value of approximately 105°C. This feature
protects the LTC4062 from excessive temperature and
allows the user to push the limits of the power handling
capability of a given circuit board without risk of damaging
the LTC4062. The charge current can be set according to
typical (not worst-case) ambient temperatures with the
assurance that the charger will automatically reduce the
current in worst-case conditions.
Undervoltage Lockout (UVLO)
An internal undervoltage lockout circuit monitors the input
voltage and keeps the charger in shutdown mode until V
CC
rises above the undervoltage lockout threshold (3.8V).
The UVLO circuit has a built-in hysteresis of 200mV.
Furthermore, to protect against reverse current in the
power MOSFET, the UVLO circuit keeps the charger in
shutdown mode if V
CC
falls to less than 45mV above the
battery voltage. Hysteresis of 145mV prevents the charger
from cycling in and out of shutdown.
Manual Shutdown
At any point in the charge cycle, the charger can be put into
shutdown mode by pulling the EN pin high. This reduces
the supply current to less than 50µA and the battery drain
current of the charger to less than 2µA. A new charge cycle
can be initiated by floating the EN pin or pulling it low.
If shutdown is not required, leaving the pin disconnected
continuously enables the circuit.
Trickle-Charge and Defective Battery Detection
When the BAT pin voltage is below the 2.9V trickle charge
threshold (V
TRIKL
), the charger reduces the charge current
to 10% of the programmed value. If the battery remains in
trickle charge for more than 25% of the total programmed
charge time, the charger stops charging and enters a
FAULT state, indicating that the battery is defective
1
. The
LTC4062 indicates the FAULT state by driving the CHRG
open-drain output with a square wave. The duty cycle of
this oscillation is 50% and the frequency is set by C
TIMER
:
fF
CHz
CHRG TIMER
=•
01 6
.µ
A LED driven by the CHRG output exhibits a pulsing
pattern, indicating to the user that the battery needs
replacing. To exit the FAULT state, the charger must be
restarted either by toggling the EN input or removing and
reapplying power to V
CC
.
Charge Status Output (CHRG)
The charge status indicator pin has three states: pull-
down, pulse at 6Hz and high impedance. In the pull-down
state, an NMOS transistor pulls down on the CHRG pin
capable of sinking up to 10mA. A pull-down state indicates
that the LTC4062 is charging a battery and the charge
current is greater than I
DETECT
(which is set by the external
component R
DET
). A high impedance state indicates that
the charge current has dropped below I
DETECT
. In the case
where the I
DET
pin is left unconnected (R
DET
= ∞, I
DETECT
= 0), a high impedance state on CHRG indicates that the
LTC4062 is not charging.
1
The Defective Battery Detection Feature is only available when time termination is being used.
LTC4062
11
4062fb
Smart Pulsing Error Feature
LTC4062 has a pulsing state at the CHRG pull-down pin of
6Hz (50% duty cycle) due to defective battery detection
(see Trickle-Charge and Defective Battery Detection sec-
tion).
Low Power Comparator (IN
+
; OUT)
The low power, low offset comparator is designed with an
internal 1V reference connected to the negative input. This
reference is generated by a precise bandgap circuit. The
–
+
1V
2
LTC4062
4062 F01
IN+
4
OUT
Figure 1. Low Power Comparator Circuit
comparator output drives a pull down NMOS transistor
able to sink up to 10mA. Voltages lower than 1V at the IN
+
pin set the OUT pin to a high impedance state.
Voltages higher than 1V plus a built-in 50mV hysteresis at
the IN
+
pin set the OUT pin to a low impedance state. The
comparator is operational even when V
CC
is not applied
provided the BAT pin voltage is greater than 2.5V. When
the voltage at the BAT pin drops below 2.5V, the compara-
tor shuts down and the current at the BAT pin is reduced
to <1µA.
OPERATIO
U
LTC4062
12
4062fb
METHOD
Charge
Time
Termination
Mode
Charge
Current
Termination
TIMER
0.1µF to
GND
IDET
RDET to
GND
CHARGER DESCRIPTION
Charges for 3 Hours. After 3 Hours, the Charger
Stops Charging and Enters Standby Mode.
Recharge Cycles Last for 1.5 Hours.
Charges for 3 Hours. After 3 Hours, the Charger
Stops Charging and Enters Standby Mode.
Recharge Cycles Last for 1.5 Hours.
Charges Until Charge Current Drops Below
IDET, Then Enters Standby Mode.
Pull-Down State When Charging. High Impedance State
When Charging Is Stopped. Pulsing State Available
When NTC Is Used and Is Still Charging.
Pull-Down State When Charging. High Impedance State
When Charging Is Stopped. Pulsing State Available
When NTC Is Used and Is Still Charging.
CHRG OUTPUT DESCRIPTION
Pull-Down State While IBAT > IDET. High Impedance
State While IBAT < IDETECT or When Charging Is Stopped.
Pulsing State Available When NTC Is Used and
Is Still Charging.
Pull-Down State While IBAT > IDETECT. High Impedance
State While IBAT < IDETECT or When Charging Is Stopped.
Pulsing State Available When NTC Is Used and
Is Still Charging.
0.1µF to
GND
GND RDET to
GND
User
Selectable
Charge
Termination
VCC RDET to
GND
Charges Indefinitely.
Charges Indefinitely.
SmartStart Is Disabled.
VCC NC Charges Indefinitely.
SmartStart Is Disabled.
Pull-Down State When Charging. High Impedance State
When Charging Is Stopped. Pulsing State Available
When NTC Is Used and Is Still Charging.
Pull-Down State When Charging. High Impedance State
When Charging Is Stopped. Pulsing State Available
When NTC Is Used and Is Still Charging.
GND NC
NC
APPLICATIO S I FOR ATIO
WUUU
Table 1
Programming Charge Termination
The LTC4062 can terminate a charge cycle using one of
several methods, allowing the designer considerable flex-
ibility in choosing an ideal charge termination algorithm.
Table 1 shows a brief description of the different termina-
tion methods and their behaviors.
Charge Time Termination
Connecting a capacitor (C
TIMER
) to the TIMER pin enables
the timer and selects charge time termination. The total
charge time is set by:
TIME HOURS C
FHOURS
TIMER
()
.•=µ01 3
When the programmed time has elapsed, the charge cycle
terminates and the charger enters standby mode. Subse-
quent recharge cycles terminate when 50% of the pro-
grammed time has elapsed. The I
DET
pin determines the
behavior of the CHRG output. Connecting a resistor (R
DET
)
from the I
DET
pin to ground sets the charge current
detection threshold, I
DETECT
:
IR
RIV
Ror
RV
I
DETECT PROG
DET CHG DET
DET DETECT
==
=
10
100
100
•
When the charge current (I
BAT
) is greater than
I
DETECT
, the CHRG output is in its pull-down state. When
the charger enters constant voltage mode operation and
the charge current falls below I
DETECT
, the CHRG output
becomes high impedance, indicating that the battery is
almost fully charged. The CHRG output will also become
high impedance once the charge time elapses. If the I
DET
pin is not connected, the CHRG output remains in its pull-
down state until the charge time elapses and terminates
the charge cycle.
Figure 2 shows a charger circuit using charge time termi-
nation that is programmed to charge at 500mA. Once the
charge current drops below 100mA in constant voltage
mode (as set by R
DET
), the CHRG output turns off the LED.
This indicates to the user that the battery is almost fully
charged and ready to use. The LTC4062 continues to
LTC4062
13
4062fb
APPLICATIO S I FOR ATIO
WUUU
charge the battery until the internal timer reaches 3 hours
(as set by C
TIMER
). During recharge cycles, the LTC4062
charges the battery until the internal timer reaches
1.5 hours. Figure 3 describes the operation of the LTC4062
charger when charge time termination is used.
Charge Current Termination
Connecting the TIMER pin to ground selects charge cur-
rent termination. With this method, the timer is disabled
and a resistor (R
DET
) must be connected from the I
DET
pin
to ground. I
DETECT
is programmed using the same equa-
tion stated in the previous section. The charge cycle
terminates when the charge current falls below I
DETECT
.
This condition is detected using an internal filtered com-
parator to monitor the I
DET
pin. When the I
DET
pin falls
below 100mV for longer than t
TERM
(typically 1.5ms),
charging is terminated.
When charging, transient loads on the BAT pin can cause
the I
DET
pin to fall below 100mV for short periods of time
before the DC current has dropped below the I
DETECT
+
VCC
CHRG
PROG
IDET CTIMER
0.1µF
VIN
4062 F02
BAT
500mA
TIMER
R
DET
1k
R
PROG
2k
LTC4062
GND
C/5
Figure 2. Time Termination Mode.
The Charge Cycle Ends After 3 Hours
Figure 3. State Diagram of a Charge Cycle
Using Charge Time Termination
CHARGE MODE
FULL CURRENT
CHRG STATE:
PULL-DOWN IF IBAT > IDETECT
Hi-Z IF IBAT < IDETECT
CHARGE TIME
ELAPSES
1/4 CHARGE TIME
ELAPSES
BAT < 4.1V
4062 F03
TRICKLE CHARGE MODE
1/10TH FULL CURRENT
BAT > 2.9V
BAT < 2.9V
2.9V < BAT < 4.1V
BAT > 4.1V
EN = 5V
OR
UVLO CONDITION
STANDBY MODE
NO CHARGE CURRENT
CHRG STATE: Hi-Z
SHUTDOWN MODE
ICC DROPS TO 20µA
CHRG STATE: Hi-Z
CHRG STATE: PULL-DOWN
DEFECTIVE BATTERY
FAULT MODE
NO CHARGE CURRENT
CHRG STATE: PULSING
RECHARGE MODE
FULL CURRENT
CHRG STATE:
PULL-DOWN IF IBAT > IDETECT
Hi-Z IF IBAT < IDETECT
1/2 CHARGE
TIME ELAPSES
POWER ON
EN = 0V
OR UVLO
CONDITION
STOPS
LTC4062
14
4062fb
APPLICATIO S I FOR ATIO
WUUU
threshold. The 1.5ms filter time (t
TERM
) on the internal
comparator ensures that transient loads of this nature do
not result in premature charge cycle termination. Once the
average
charge current drops below I
DETECT
, the charger
terminates the charge cycle.
The CHRG output is in a pull-down state while charging
and in a high impedance state once charging has stopped.
Figure 4 describes the operation of the LTC4062 charger
when charge current termination is used.
When the charger is set for charge current termination and
the battery is removed from the charger, a sawtooth
waveform of several hundred mV will appear at the charger
output. This is caused by the repeated cycling between
termination and recharge events. This cycling results in
pulsing at the CHRG output. If an LED is connected to this
pin, it will exhibit a pulsing pattern, indicating to the user
that a battery is not present. The frequency of the sawtooth
is dependent on the amount of output capacitance.
Figure 4. State Diagram of a Charge Cycle Using Charge Current Termination
CHARGE MODE
FULL CURRENT
I
BAT
< I
DETECT
IN VOLTAGE MODE
4062 F04
TRICKLE CHARGE MODE
1/10TH FULL CURRENT
BAT > 2.9V
BAT < 2.9V
2.9V < BAT < 4.1V
BAT > 4.1V
BAT < 4.1V
EN = 5V
OR
UVLO CONDITION
STANDBY MODE
NO CHARGE CURRENT
CHRG STATE: Hi-Z
SHUTDOWN MODE
I
CC
DROPS TO 20µA
CHRG STATE: Hi-Z
CHRG STATE: PULL-DOWN
CHRG STATE: PULL-DOWN
POWER ON
EN = 0V
OR UVLO
CONDITION
STOPS
CHARGE MODE
FULL CURRENT
4062 F05
TRICKLE CHARGE MODE
1/10TH FULL CURRENT
BAT > 2.9V
BAT < 2.9V
2.9V < BAT EN = 5V
OR
UVLO CONDITION
SHUTDOWN MODE
ICC DROPS TO 20µA
CHRG STATE: Hi-Z
CHRG STATE: PULL-DOWN
POWER ON
EN = 0V
OR UVLO
CONDITION
STOPS
CHRG STATE:
PULL-DOWN IF IBAT > IDETECT
Hi-Z IF IBAT < IDETECT
Figure 5. State Diagram of a Charge Cycle Using User-Selectable Termination
LTC4062
15
4062fb
APPLICATIO S I FOR ATIO
WUUU
User-Selectable Charge Termination
Connecting the TIMER pin to V
CC
selects user-selectable
charge termination, in which all of the internal termination
features are disabled. The charge cycle continues indefi-
nitely until the charger is shut down through the EN pin.
The I
DET
pin programs the behavior of the CHRG output in
the same manner as when using charge time termination.
If the I
DET
pin is not connected, the CHRG output remains
in its pull-down state until the charger is shut down.
With user-selectable charge termination, the SmartStart
feature is disabled; when the charger is powered on or
enabled, the LTC4062 automatically begins charging, re-
gardless of the battery voltage. Figure 5 describes charger
operation when user-selectable charge termination is used.
Programming C/10 Current Detection/Termination
In most cases, an external resistor, R
DET
, is needed to set
the charge current detection threshold, I
DETECT
. However,
when setting I
DETECT
to be 1/10th of I
CHG
, the I
DET
pin can
be connected directly to the PROG pin. This reduces the
component count, as shown in Figure 6.
When PROG and I
DET
are connected in this way, the full-
scale charge current, I
CHG
, is programmed with a different
equation:
RV
IIV
R
PROG CHG CHG PROG
==
500 500
,
Stability Considerations
The battery charger constant voltage mode feedback loop
is stable without any compensation provided a battery is
connected. However, a 1µF capacitor with a 1Ω series
resistor to GND is recommended at the BAT pin to reduce
noise when no battery is present.
When the charger is in constant current mode, the PROG
pin is in the feedback loop, not the battery. The constant
current stability is affected by the impedance at the PROG
pin. With no additional capacitance on the PROG pin, the
charger is stable with program resistor values as high as
10kΩ; however, additional capacitance on this node re-
duces the maximum allowed program resistor value.
Power Dissipation
When designing the battery charger circuit, it is not
necessary to design for worst-case power dissipation
scenarios because the LTC4062 automatically reduces
the charge current during high power conditions. The
conditions that cause the LTC4062 to reduce charge
current through thermal feedback can be approximated
by considering the power dissipated in the IC. Most of the
power dissipation is generated from the internal charger
MOSFET. Thus, the power dissipation is calculated to be
approximately:
P
D
= (V
CC
– V
BAT
) • I
BAT
P
D
is the power dissipated, V
CC
is the input supply voltage,
V
BAT
is the battery voltage and I
BAT
is the charge current.
The approximate ambient temperature at which the ther-
mal feedback begins to protect the IC is:
T
A
= 105°C – P
D
• θ
JA
T
A
= 105°C – (V
CC
– V
BAT
) • I
BAT
• θ
JA
+
VCC
PROG
IDET
VIN BAT
500mA
TIMER
RDET
2k
RPROG
2k
LTC4062
GND
+
VCC
PROG
IDET
VIN
4062 F06
BAT
500mA
TIMER
R
PROG
1k
LTC4062
GND
C/5
C/5
Figure 6. Two Circuits That Charge at 500mA
Full-Scale Current and Terminate at 50mA
LTC4062
16
4062fb
APPLICATIO S I FOR ATIO
WUUU
Example: An LTC4062 operating from a 5V wall adapter is
programmed to supply 800mA full-scale current to a
discharged Li-Ion battery with a voltage of 3.3V. Assuming
θ
JA
is 40°C/W (see Thermal Considerations), the ambient
temperature at which the LTC4062 will begin to reduce the
charge current is approximately:
T
A
= 105°C – (5V – 3.3V) • (800mA) • 40°C/W
T
A
= 105°C – 1.36W • 40°C/W = 105°C – 54.4°C
T
A
= 50.6°C
The LTC4062 can be used above 50.6°C ambient, but the
charge current will be reduced from 800mA. The approxi-
mate current at a given ambient temperature can be
approximated by:
ICT
VV
BAT A
CC BAT JA
=°105 –
(– )•θ
Using the previous example with an ambient temperature
of 60°C, the charge current will be reduced to
approximately:
ICC
VVCW
C
CA
ImA
BAT
BAT
=°°
°=°
°
=
105 60
53340
45
68
662
–
(–.)• / /
It is important to remember that LTC4062 applications do
not need to be designed for worst-case thermal condi-
tions, since the IC will automatically reduce power dissi-
pation if the junction temperature reaches approximately
105°C.
Thermal Considerations
In order to deliver maximum charge current under all
conditions, it is critical that the exposed metal pad on the
backside of the LTC4062 package is properly soldered to
the PC board ground. Correctly soldered to a 2500mm
2
double sided 1oz copper board, the LTC4062 has a ther-
mal resistance of approximately 40°C/W. Failure to make
thermal contact between the exposed pad on the backside
of the package and the copper board will result in thermal
resistances far greater than 40°C/W. As an example, a
correctly soldered LTC4062 can deliver over 800mA to a
battery from a 5V supply at room temperature. Without a
good backside thermal connection, this number could
drop to less than 500mA.
V
CC
Bypass Capacitor
Many types of capacitors can be used for input bypassing;
however, caution must be exercised when using multi-
layer ceramic capacitors. Because of the self-resonant and
high Q characteristics of some types of ceramic capaci-
tors, high voltage transients can be generated under some
start-up conditions such as connecting the charger input
to a live power source. Adding a 1.5Ω resistor in series
with an X5R ceramic capacitor will minimize start-up
voltage transients. For more information, see Application
Note 88.
Charge Current Soft-Start and Soft-Stop
The LTC4062 includes a soft-start circuit to minimize the
inrush current at the start of a charge cycle. When a charge
cycle is initiated, the charge current ramps from zero to the
full-scale current over a period of approximately 100µs.
Likewise, internal circuitry slowly ramps the charge cur-
rent from full-scale to zero when the charger is shut off or
self terminates. This has the effect of minimizing the
transient current load on the power supply during start-up
and charge termination.
Reverse Polarity Input Voltage Protection
In some applications, protection from reverse polarity on
V
CC
is desired. If the supply voltage is high enough, a
series blocking diode can be used. In other cases, where
the diode voltage drop must be kept low, a P-channel
MOSFET can be used (as shown in Figure 7).
Figure 7. Low Loss Input Reverse Polarity Protection
V
CC
V
IN
4062 F07
LTC4062
DRAIN-BULK
DIODE OF FET
LTC4062
17
4062fb
APPLICATIO S I FOR ATIO
WUUU
Figure 8. Combining Wall Adapter and USB Power
+
VCC
D1
PROG
IDET
3.3k
2k
MN1
5V WALL
ADAPTER
ICHG = 800mA
USB POWER
ICHG = 500mA MP1
4062 F08
BAT
LTC4062
1.24k
Li-Ion
BATTERY
SYSTEM
LOAD
1k
C/5
USB and Wall Adapter Power
The LTC4062 allows charging from both a wall adapter
and a USB port. Figure 8 shows an example of how to
combine wall adapter and USB power inputs. A P-channel
MOSFET, MP1, is used to prevent back conducting into the
USB port when a wall adapter is present and a Schottky
diode, D1, is used to prevent USB power loss through the
1kΩ pull-down resistor.
Typically a wall adapter can supply more current than
the 500mA limited USB port. Therefore, an N-channel
MOSFET, MN1, and an extra 3.3kΩ program resistor are
used to increase the charge current to 800mA when the
wall adapter is present.
LTC4062
18
4062fb
TYPICAL APPLICATIO S
U
+
VCC
TIMER
BAT
PROG
IDET
LTC4062
GND 2k 2.5k
5V
WALL ADAPTER
USB
POWER
4062 TA04
Li-Ion
CELL
1µF
C/5
400mA
Full-Featured Li-Ion Charger with Low-Battery Comparator (Using Time Termination)
USB/Wall Adapter Power Li-Ion Charger
(Using Charge Current Termination)
+
TIMER
PROG
EN
C/5
I
OUT
BAT
V
IN
4.3V TO 8V
IN
+
DET
LTC4062
GND
1.24k 619Ω
100k
715k
347k
800mA
1µF
0.1µF
4062 TA03
SINGLE-CELL
Li-Ion BATTERY
V
CC
BAT > 3V BAT < 3V
LTC4062
19
4062fb
DD Package
10-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1669)
PACKAGE DESCRIPTIO
U
3.00 0.10
(4 SIDES)
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2).
CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
0.38 0.10
BOTTOM VIEW—EXPOSED PAD
1.65 0.10
(2 SIDES)
0.75 0.05
R = 0.115
TYP
2.38 0.10
(2 SIDES)
15
106
PIN 1
TOP MARK
(SEE NOTE 6)
0.200 REF
0.00 – 0.05
(DD10) DFN 1103
0.25 0.05
2.38 0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
1.65 0.05
(2 SIDES)2.15 0.05
0.50
BSC
0.675 0.05
3.50 0.05
PACKAGE
OUTLINE
0.25 0.05
0.50 BSC
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 represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
LTC4062
20
4062fb
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATIO N 2005
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with Integrated Pass Transistor in ThinSOT C/10 Indicator, Up to 800mA Charge Current
LTC4057 Lithium-Ion Linear Battery Charger Up to 800mA Charge Current, Thermal Regulation, ThinSOT Package
LTC4058 Standalone 950mA Lithium-Ion Charger in DFN C/10 Charge Termination, Battery Kelvin Sensing, ±7% Charge Accuracy
LTC4059 900mA Linear Lithium-Ion Battery Charger 2mm × 2mm DFN Package, Thermal Regulation, Charge Current Monitor
Output
LTC4061/ Standalone Li-Ion Chargers with Thermistor 4.2V/4.4V, ±0.35%/±0.4% Float Voltage, Up to 1A Charge Current,
LTC4061-4.4 Thermistor Input, 3mm × 3mm DFN Package
LTC4063 Li-Ion Charger with Linear Regulator Up to 1A Charge Current, 100mA, 125mV LDO, 3mm × 3mm DFN
LTC4411/LTC4412 Low Loss PowerPathTM Controller in ThinSOT Automatic Switching Between DC Sources, Load Sharing,
Replaces ORing Diodes
Power Management
LTC3405/LTC3405A 300mA (I
OUT
), 1.5MHz, Synchronous Step-Down 95% Efficiency, V
IN
: 2.7V to 6V, V
OUT
= 0.8V, I
Q
= 20µA, I
SD
< 1µA,
DC/DC Converter ThinSOT Package
LTC3406/LTC3406A 600mA (I
OUT
), 1.5MHz, Synchronous Step-Down 95% Efficiency, V
IN
: 2.5V to 5.5V, V
OUT
= 0.6V, I
Q
= 20µA, I
SD
< 1µA,
DC/DC Converter ThinSOT Package
LTC3411 1.25A (I
OUT
), 4MHz, Synchronous Step-Down 95% Efficiency, V
IN
: 2.5V to 5.5V, V
OUT
= 0.8V, I
Q
= 60µA, I
SD
< 1µA,
DC/DC Converter MS Package
LTC3440 600mA (I
OUT
), 2MHz, Synchronous Buck-Boost 95% Efficiency, V
IN
: 2.5V to 5.5V, V
OUT
= 2.5V, I
Q
= 25µA, I
SD
< 1µA,
DC/DC Converter MS Package
LTC4413 Dual Ideal Diode in DFN 2-Channel Ideal Diode ORing, Low Forward On-Resistance, Low Regulated
Forward Voltage, 2.5V ≤ V
IN
≤ 5.5V
ThinSOT and PowerPath are trademarks of Linear Technology Corporation.
