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TECHNOLOGY
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CHARGE cunnmnmm
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L7 LJUW 1
LTC4061
1
4061fd
Typical applicaTion
FeaTures DescripTion
Standalone Linear Li-Ion
Battery Charger with
Thermistor Input
The LTC
®
4061 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 application. Additional safety features designed
to maximize battery lifetime and reliability include NTC
battery temperature sensing and the SmartStart charg-
ing algorithm.
No external sense resistor or external blocking diode is
required for charging due to the internal MOSFET archi-
tecture. Internal thermal feedback regulates the charge
current to maintain a constant die temperature during
high power operation or high ambient temperature condi-
tions. The charge current is programmed with an external
resistor. With power applied, the LTC4061 can be put into
shutdown mode to reduce the supply current to 20µA and
the battery drain current to less than 5µA.
Other features include smart recharge, USB C/5 cur-
rent programming input, undervoltage lockout and AC
Present logic output.
applicaTions
n Charge Current Programmable Up to 1A
n Charges Single-Cell Li-Ion Batteries Directly from
USB Port
n Preset Charge Voltage with ±0.35% Accuracy
n Thermistor Input for Temperature Qualified
Charging
n Input Supply Present Logic Output
n Thermal Regulation Maximizes Charge Rate
Without Risk of Overheating
n Programmable Charge Current Detection/
Termination
n Programmable Charge Termination Timer
n Smart Pulsing Error Feature
n SmartStart™ Prolongs Battery Life
n 20µA Charger Quiescent Current in Shutdown
n Available in a Low Profile (0.75mm) 10-Lead
(3mm × 3mm) DFN Package
n Handheld Computers
n Portable MP3 Players
n Digital Cameras
800mA Single-Cell Li-Ion Battery Charger
(C/10 Termination)
Complete Charge Cycle (1100mAh Battery)
VCC
TIMER
PROG
IDET
BAT
800mA
VIN
4.3V TO 8V
4.2V
SINGLE-CELL
Li-Ion BATTERY
+
619Ω
1µF
ACPR
NTC
LTC4061
GND
4061 TA01a
CHRG
EN
C/5
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
4061 TA01b
1.0
BATTERY
CURRENT
BATTERY
VOLTAGE
VCC = 5V
TA = 25°C
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
SmartStart, ThinSOT and PowerPath are trademarks of Linear Technology Corporation. All
other trademarks are the property of their respective owners. Protected by U.S. Patents
including 6522118.
LTC406 1
TOP wEw
2 L7LJ1‘JW
LTC4061
2
4061fd
pin conFiguraTionabsoluTe MaxiMuM raTings
Input Supply Voltage (VCC) ........................ –0.3V to 10V
EN,
ACPR, CHRG, NTC, PROG,
C/5, BAT ..................................................... –0.3V to 10V
TIMER, IDET .................................... –0.3V to VCC + 0.3V
BAT Short-Circuit Duration ...........................Continuous
VCC Pin Current ...........................................................1A
BAT Pin Current ..........................................................1A
Maximum Junction Temperature (Note 5) ............ 125°C
Operating Temperature Range (Note 2) ...–40°C to 85°C
Storage Temperature Range .................. –65°C to 125°C
(Note 1)
TOP VIEW
10
9
6
7
8
11
4
5
3
2
1VCC
PROG
IDET
EN
C/5
BAT
NTC
TIMER
ACPR
CHRG
DD PACKAGE
10-LEAD (3mm s 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 40°C/W (NOTE 3)
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC4061EDD#PBF LTC4061EDD#TRPBF LBJS 10-Lead (3mm × 3mm) Plastic DFN –40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
elecTrical characTerisTics
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
VCC Input Supply Voltage l4.3 8 V
ICC Input Supply Current Charge Mode (Note 4), RPROG = 10k
Standby Mode, Charge Terminated
Shutdown (EN = 5V, VCC < VBAT or VCC < VUV)
l
l
l
240
130
20
500
300
50
µA
µA
µA
VFLOAT VBAT Regulated Output Voltage
0 ≤ TA ≤ 85°C
4.185
4.175
4.2
4.2
4.215
4.225
V
V
IBAT BAT Pin Current RPROG = 10k, Constant Current Mode
RPROG = 1.25k, Constant Current Mode
Standby Mode, Charge Terminated, VBAT = 4.2V
Shutdown Mode, VBAT = 4.2V
l
l
l
l
93
760
100
800
–3.5
±1
107
840
–7
±5
mA
mA
µA
µA
VPROG PROG Pin Voltage RPROG = 10k, Constant Current Mode
RPROG = 1.25k, Constant Current Mode
0.97
0.97
1
1
1.03
1.03
V
V
VACPR ACPR Output Low Voltage IACPR = 5mA 0.1 0.25 V
VCHRG CHRG Output Low Voltage ICHRG = 5mA 0.1 0.25 V
ITRIKL Trickle Charge Current VBAT < VTRIKL, RPROG = 10k
VBAT < VTRIKL, RPROG = 1.25k
6
60
10
80
14
100
mA
mA
VTRIKL Trickle Charge Threshold Voltage VBAT Rising
Hysteresis
2.8 2.9
100
3 V
mV
VUV VCC Undervoltage Lockout Voltage From Low to High
Hysteresis
3.7 3.8
200
3.9 V
mV
VASD VCC – VBAT Lockout Threshold Voltage VCC from Low to High, VBAT = 4.3V
VCC from High to Low, VBAT = 4.3V
145
10
190
45
230
75
mV
mV
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise noted.
LTCAOé 1
L7 LJUW 3
LTC4061
3
4061fd
elecTrical characTerisTics
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 LTC4061 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.
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
REN EN Pin Pull-Down Resistor l2 3.4 5 MΩ
VEN EN Input Threshold Voltage EN Rising, 4.3V < VCC < 8V
Hysteresis
0.4 0.7
70
1 V
mV
VCT Charge Termination Mode Threshold
Voltage
VTIMER from High to Low
Hysteresis
0.4 0.7
50
1 V
mV
VUT User Termination Mode Threshold
Voltage
VTIMER from Low to High
Hysteresis
3.9 4.2
50
V
mV
IDETECT Charge Current Detection Threshold RDET = 1k, 0 ≤ TA ≤ 85°C
RDET = 2k, 0 ≤ TA ≤ 85°C
RDET = 10k, 0 ≤ TA ≤ 85°C
RDET = 20k, 0 ≤ TA ≤ 85°C
90
45
8
3.8
100
50
10
5
110
55
12
6.2
mA
mA
mA
mA
ΔVRECHRG Recharge Threshold Voltage VFLOAT – VRECHRG, 0 ≤ TA ≤ 85°C 65 100 135 mV
tSS Soft-Start Time IBAT from 0 to ICHRG 100 µs
tTERM Termination Comparator Filter Time Current Termination Mode 0.8 1.5 2.5 ms
tRECHRG Recharge Comparator Filter Time 3 7 14 ms
tTIMER Charge Cycle Time CTIMER = 0.1µF 2.55 3 3.45 hr
RC/5 C/5 Pin Pull-Down Resistor l2 3.4 5 MΩ
VC/5 C/5 Input Threshold Voltage C/5 Rising, 4.3V < VCC < 8V
Hysteresis
0.4 0.7
70
1 V
mV
VNTC-HOT NTC Pin Hot Threshold Voltage VNTC Falling
VNTC Rising
0.35 • VCC
0.36 • VCC
V
V
VNTC-COLD NTC Pin Cold Threshold Voltage VNTC Rising
VNTC Falling
0.76 • VCC
0.75 • VCC
V
V
VNTC-DIS NTC Pin Disable Threshold Voltage VNTC Falling
Hysteresis
70 85
50
100 mV
mV
fCHRG NTC Fault Pulsing Frequency Current/User Termination Mode
Time Termination Mode CTIMER = 0.1µF
1
1.5
1.5
2
Hz
Hz
TLIM Junction Temperature in Constant
Temperature Mode
105 °C
RON Power FET On-Resistance
(Between VCC and BAT)
VBAT = 3.85V, ICC = 175mA, RPROG = 2k 375 mΩ
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise noted.
Note 4: Supply current includes PROG pin current and IDET 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.
LTC406 1
425
4 215 4 26
g a / ~ g
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E (m)
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(m
\
LTC4061
4
4061fd
Typical perForMance characTerisTics
CHARGE CURRENT (mA)
0
VBAT (V)
600 1000
4061 G01
200 400 800
4.26
4.24
4.22
4.20
4.18
4.16
4.14
4.12
4.10
VCC = 5V
RPROG = 1k
TEMPERATURE (°C)
–50
VFLOAT (V)
4.215
4.210
4.205
4.200
4.195
4.190
4.185 –25 0 25 50
4061 G02
75 100
VCC = 5V
RPROG = 10k
4061 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
VPROG (V)
0
IBAT (mA)
1200
1000
800
600
400
200
00.2 0.4 0.6 0.8
4061 G04
1.0 1.2
VCC = 5V
RPROG = 1k
C/5 = 5V
VTIMER = 5V
–50 –25 0 25 50 75 100
TEMPERATURE (°C)
VPROG (V)
4061 G05
1.006
1.004
1.002
1.000
0.998
0.996
0.994
RPROG = 10k
C/5 = VCC
VCC = 4.3V
VCC = 8V
4061 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
–50 –25 0 25 50 75 100
TEMPERATURE (°C)
ITRICKLE (mA)
84
82
80
78
76
4061 G07
VCC = 5V
VBAT = 2.5V
RPROG = 1.25k
–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
4061 G08
VCC = 5V
RPROG = 1.25k
VBAT (V)
3.0
IBAT (mA)
550
450
350
250
150
50 3.8
4061 G09
3.2 3.4 3.6 4.0
VCC = 5V
RPROG = 2k
C/5 = 5V
C/5 = 0V
Battery Regulated Output (Float)
Voltage vs Charge Current
Battery Regulated Output (Float)
Voltage vs Temperature
PROG Pin Voltage vs Temperature
(Constant-Current Mode)
Charge Current vs PROG Pin
Voltage
Trickle Charge Current
vs Temperature
Trickle Charge Threshold Voltage
vs Temperature Charge Current vs Battery Voltage
Battery Regulated Output (Float)
Voltage vs Supply Voltage
PROG Pin Voltage vs VCC
(Constant-Current Mode)
LTCAOé 1
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L7 LJUW 5
LTC4061
5
4061fd
Typical perForMance characTerisTics
NTC Fault Pulsing Frequency
vs VCC
NTC Fault Pulsing Frequency
vs Temperature
Charge Current vs Ambient
Temperature with Thermal
Regulation Charge Current vs Supply Voltage
Recharge Threshold Voltage
vs Temperature
Power FET On-Resistance
vs Temperature
Internal Charge Timer
vs Temperature
Undervoltage Lockout Voltage
vs Temperature Charge Current vs Battery Voltage
–50 –25 0 25 50 75 100
TEMPERATURE (°C)
tTIMER (MINUTES)
195
190
185
180
175
170
165
4061 G10
CTIMER = 0.1µF
VCC = 4.3V
VCC = 8V
4061 G11
VCC (V)
4.0
fCHRG (Hz)
8.0
5.0 6.0 7.0
1.60
1.55
1.50
1.45
1.40
1.35
1.30 4.5 5.5 6.5 7.5
CTIMER = 0.1µF
TEMPERATURE (°C)
–50
1.7
1.6
1.5
1.4
1.3
1.2
–25 0 25 50
4061 G12
75 100
CTIMER = 0.1µF
VCC = 8V
VCC = 4.3V
fCHRG (Hz)
TEMPERATURE (°C)
–50 –25
0
IBAT (mA)
400
1000
050 75
4061 G13
200
800
600
25 100 125
RPROG = 1.25k
ONSET OF THERMAL
REGULATION
RPROG = 2k
4061 G14
VCC (V)
4.0
IBAT (mA)
8.0
5.0 6.0 7.0
104
102
100
98
96 4.5 5.5 6.5 7.5
VCC = 5V
VBAT = 4V
C/5 = 5V
RPROG = 10k
TEMPERATURE (°C)
–50
VRECHARGE (V)
4.16
4.14
4.12
4.10
4.08
4.06
4.04 –25 0 25 50
4061 G15
75 100
VCC = 8V
VCC = 4.3V
TEMPERATURE (°C)
–50
500
450
400
350
300
250
–25 0 25 50
4061 G16
75 100
VCC = 4V
IBAT = 200mA
4061 G17
TEMPERATURE (°C)
–50 25 75
–25 0 50 100
VUV (V)
3.900
3.875
3.850
3.825
3.800
3.775
3.750
3.725
3.700
4061 G18
VBAT (V)
0
IBAT (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
LTC406 1
kg (Mn)
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v toerch
LTC4061
6
4061fd
4061 G19
TEMPERATURE (°C)
–50 25 75
–25 0 50 100
4.0
3.5
3.0
2.5
2.0
1.5
4061 G20
TEMPERATURE (°C)
–50 25 75
–25 0 50 100
4.0
3.5
3.0
2.5
2.0
1.5
TEMPERATURE (°C)
–50
VEN (mV)
900
850
800
750
700
650
600 –25 0 25 50
4061 G21
75 100
VCC = 5V
4061 G22
TEMPERATURE (°C)
–50 25 75
–25 0 50 100
VC/5 (mV)
900
850
800
750
700
650
600
VCC = 5V
TEMPERATURE (°C)
–50
ICC (µA)
70
60
50
40
30
20
10 –25 0 25 50
4061 G23
75 100
EN = VCC
VCC = 4.3V
VCC = 8V
VCC = 5V
IACPR (mA)
4061 G24
VACPR (V)
0 4
123
160
140
120
100
80
60
40
20
0
VCC = 5V
VBAT = 4V TA = –40°C
TA = 25°C
TA = 90°C
4061 G25
TEMPERATURE (°C)
–50
VCHRG (V)
0.6
0.5
0.4
0.3
0.2
0.1
025 75
–25 0 50 100
VCC = 5V
ICHRG = 5mA
4061 G26
TEMPERATURE (°C)
–50
VACPR (V)
0.6
0.5
0.4
0.3
0.2
0.1
025 75
–25 0 50 100
VCC = 5V
IACPR = 5mA
VCHRG (V)
0
ICHRG (mA)
160
140
120
100
80
60
40
20
012 3 4
4061 G27
VCC = 5V
VBAT = 4V
TA = 25°C
TA = –40°C
TA = 90°C
Typical perForMance characTerisTics
EN Pin Pulldown Resistance vs
Temperature
C/5 Pin Threshold Voltage
(High-to-Low) vs Temperature
C/5 Pin Pulldown Resistance vs
Temperature
CHRG Pin Output Low Voltage vs
Temperature
ACPR Pin Output Low Voltage vs
Temperature
Shutdown Supply Current vs
Temperature and VCC
EN Pin Threshold Voltage
(On-to-Off) vs Temperature
ACPR Pin I-V Curve
CHRG Pin I-V Curve
LTCAOé 1
L7 LJUW 7
LTC4061
7
4061fd
pin FuncTions
BAT (Pin 1): Charge Current Output. This pin provides
charge current to the battery and regulates the final float
voltage to 4.2V.
NTC (Pin 2): Input to the NTC (Negative Temperature Coef-
ficient) Thermistor Temperature Monitoring Circuit. Under
normal operation, connect a thermistor from the NTC pin
to ground and a resistor of equal value from the NTC pin
to VCC. When the voltage at this pin drops below 0.35 •
VCC at hot temperatures or rises above 0.76 • VCC at cold,
charging is suspended, the internal timer is frozen and the
CHRG pin output will start to pulse at 1.5Hz. Pulling this
pin below 0.016 • VCC disables the NTC feature. There is
approximately 2°C of temperature hysteresis associated
with each of the input comparators thresholds.
TIMER (Pin 3): Timer Program and Termination Select Pin.
This pin selects which method is used to terminate the
charge cycle. Connecting a capacitor, CTIMER, to ground
selects charge time termination. The charge time is set
by the following formula:
TIME HOURS HOURS C
µF or
C µF TI
TIMER
TIMER
( ) • .
. •
=
=
30 1
0 1 MME HOURS
HOURS
( )
( )3
Connecting the TIMER pin to ground selects charge cur-
rent termination, while connecting the pin to VCC selects
user termination. See Applications Information for more
information on current and user termination.
ACPR (Pin 4): Open-Drain Power Supply Present Status
Output. The power supply status indicator pin has two
states: pull-down 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 ACPR pin. The state of this pin
is dependent on the value of VCC and BAT: it requires that
VCC is 190mV greater than VBAT and greater than VUVLO.
See Applications Information.
CHRG (Pin 5): Open-Drain Charge Status Output. The
charge status indicator pin has three states: pull-down,
pulse at 1.5Hz or 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 IDETECT as well as the termina-
tion method being used and the state of the NTC pin. See
Applications Information.
C/5 (Pin 6): C/5 Enable Input. Used to control the amount
of current drawn from the 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.
IDET (Pin 8): Current Detection Threshold Program Pin.
The current detection threshold, IDETECT, is set by con-
necting a resistor, RDETECT, to ground. IDETECT is set by
the following formula:
IR
RIV
Ror
RV
I
DETECT PROG
DET CHG DET
DET DE
= =
=
10
100
100
•
TTECT
The CHRG pin becomes high impedance when the charge
current drops below IDETECT. IDETECT can be set to 1/10th
the programmed charge current by connecting IDET di-
rectly to PROG. If the IDET 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
LTC406 1
_|,|__,_-r
E]—>
L7LJCUEN2
LTC4061
8
4061fd
block DiagraM
pin FuncTions
resistor, RPROG, 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
VCC (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 pad package and must be soldered to the
PCB copper for minimal thermal resistance.
–
+
–
+
–+
11983
CA
MA
1.2V
2.9V
PROGIDET
RDET
CTIMER RPROG
0.1V TO BAT
0.2V
1V
0.1V
–+–+
C3C2
LOGIC
TA
TDIE
105°C
SHDN
4061 BD
GND
–+
VA
BAT
1000s1s1s
VCC
1
10
IDETECT
RECHRG
4.1V
TO BAT
EN
3M
SEL
TIMER
COUNTER
OSCILLATOR
NTC
LOGIC
EN
C/5
C/5
C/5
STOP
CHRG
ACPR
3M
5
6
7
–
+
C1
ACPR
4
2
HOT COLD DIS
LTCAOé 1
L7 LJUW 9
LTC4061
9
4061fd
operaTion
The LTC4061 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
LTC4061 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 VCC 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 LTC4061 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 LTC4061
enters constant voltage mode and the charge current
decreases as the battery becomes fully charged.
The LTC4061 offers several methods with which to ter-
minate 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 resis-
tor to the IDET 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 VCC 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 ap-
plying the following equation:
IV
R
BAT PROG
PROG
=• 1000
SmartStart
When the LTC4061 is initially powered on or brought out
of shutdown mode, the charger checks the battery volt-
age. If the BAT pin is below the recharge threshold of 4.1V
(which corresponds to approximately 80-90% battery
capacity), the LTC4061 enters charge mode and begins a
full charge cycle. If the BAT pin is above 4.1V, the LTC4061
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 LTC4061
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
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 LTC4061 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 LTC4061. 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.
LTc4061
LTC4061
10
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Undervoltage Lockout (UVLO)
An internal undervoltage lockout circuit monitors the
input voltage and keeps the charger in shutdown mode
until VCC 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 VCC 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.
T
rickle-Charge and Defective Battery Detection
When the BAT pin voltage is below the 2.9V trickle charge
threshold (VTRIKL), 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 defective1. The LTC4061
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 CTIMER:
fµF
CHz
CHRG TIMER
=0 1 6
.•
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 VCC.
Charge Status Output (CHRG)
The charge status indicator pin has three states: pull-down,
pulse at 1.5Hz or 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 LTC4061 is charging a battery and the charge cur-
rent is greater than IDETECT (which is set by the external
component RDET). A high impedance state indicates that
the charge current has dropped below IDETECT
. In the
case where the IDET pin is left unconnected (RDET = ∞,
IDETECT = 0), a high impedance state on CHRG indicates
that the LTC4061 is not charging.
Smart Pulsing Error Feature
LTC4061 has two different pulsing states at CHRG pull-
down pin:
1. 6Hz (50% duty cycle) due to defective battery detection
(see Trickle-Charge and Defective Battery Detection
section);
2. 1.5Hz (25% duty cycle if in time termination, 50% duty
cycle if in charge current or user termination) due to
NTC out-of-temperature condition.
NTC Thermistor (NTC)
The temperature of the battery is measured by placing
a negative temperature coefficient (NTC) thermistor
close to the battery pack. The NTC circuitry is shown in
Figure 1. To use this feature, connect the NTC thermistor,
RNTC, between the NTC pin and ground and a resistor,
RNOM, from the NTC pin to VCC. RNOM should be a 1%
resistor with a value equal to the value of the chosen NTC
thermistor at 25°C (this value is 100kΩ for a Vishay NTH-
S0603N01N1003J thermistor). The LTC4061 goes into hold
mode when the resistance, RHOT, of the NTC thermistor
drops to 0.53 times the value of RNOM or approximately
53kΩ, which corresponds to approximately 40°C. Hold
mode freezes the timer and stops the charge cycle until the
thermistor indicates a return to a valid temperature. As the
temperature drops, the resistance of the NTC thermistor
rises. The LTC4061 is designed to go into hold mode when
the value of the NTC thermistor increases to 3.26 times
the value of RNOM This resistance is RCOLD. For a Vishay
NTHS0603N01N1003J thermistor, this value is 326kΩ,
which corresponds to approximately 0°C. The hot and cold
comparators each have approximately 2°C of hysteresis
to prevent oscillation about the trip point. Grounding the
NTC pin disables the NTC function. For more details refer
to the Application Information section.
1 The Defective Battery Detection feature is only available when time termination is being used.
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Figure 1. NTC Circuit Information
–
+
–
+
–
+
0.35 • VCC
0.76 • VCC
0.016 • VCC
TOO COLD
TOO HOT
ENABLE
RNTC
RNOM
2
LTC4061
VCC
4061 F01
NTC
applicaTions inForMaTion
Programming Charge Termination
The LTC4061 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 termination
methods and their behaviors.
Charge Time Termination
Connecting a capacitor (CTIMER) to the TIMER pin enables
the timer and selects charge time termination. The total
charge time is set by:
TIME HOURS C
µF HOURS
TIMER
( ) .•=0 1 3
Table 1.
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
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When the programmed time has elapsed, the charge
cycle terminates and the charger enters standby mode.
Subsequent recharge cycles terminate when 50% of the
programmed time has elapsed. The IDET pin determines
the behavior of the CHRG output. Connecting a resistor
(RDET) from the IDET pin to ground sets the charge current
detection threshold, IDETECT:
IR
RIV
Ror
RV
I
DETECT PROG
DET CHG DET
DET DE
= =
=
10
100
100
•
TTECT
When the charge current (IBAT) is greater than
IDETECT, the CHRG output is in its pull-down state. When
the charger enters constant voltage mode operation and
the charge current falls below IDETECT, 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 IDET
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 RDET), the CHRG output turns off the
LED. This indicates to the user that the battery is almost
fully charged and ready to use. The LTC4061 continues
to charge the battery until the internal timer reaches 3
hours (as set by CTIMER). During recharge cycles, the
LTC4061 charges the battery until the internal timer reaches
1.5 hours. Figure 3 describes the operation of the LTC4061
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 (RDET) must be connected from the IDET
pin to ground. IDETECT is programmed using the same
equation stated in the previous section. The charge cycle
terminates when the charge current falls below IDETECT.
This condition is detected using an internal filtered
comparator to monitor the IDET pin. When the IDET pin
falls below 100mV for longer than tTERM (typically 1ms),
charging is terminated.
When charging, transient loads on the BAT pin can cause
the IDET pin to fall below 100mV for short periods of time
before the DC current has dropped below the IDETECT
threshold. The 1.5ms filter time (tTERM) 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 IDETECT, 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 LTC4061 charger
when charge current termination is used.
User-Selectable Charge Termination
Connecting the TIMER pin to VCC 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 IDET pin programs the behavior of the CHRG output in
the same manner as when using charge time termination.
If the IDET 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 LTC4061 automatically begins charging,
regardless of the battery voltage. Figure 5 describes
charger operation when user-selectable charge termina-
tion is used.
+
VCC
CHRG
PROG
IDET CTIMER
0.1µF
VIN
4061 F02
BAT
500mA
TIMER
RDET
1k
RPROG
2k
LTC4061
GND
C/5
Figure 2. Time Termination Mode.
The Charge Cycle Ends After 3 Hours.
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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
4061 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
Figure 3. State Diagram of a Charge Cycle Using Charge Time Termination
LTc4061
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CHARGE MODE
FULL CURRENT
IBAT < IDETECT
IN VOLTAGE MODE
4061 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
ICC 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
4061 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 4. State Diagram of a Charge Cycle Using Charge Current Termination
Figure 5. State Diagram of a Charge Cycle Using User-Selectable Termination
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Programming C/10 Current Detection/Termination
In most cases, an external resistor, RDET, is needed to set
the charge current detection threshold, IDETECT. However,
when setting IDETECT to be 1/10th of ICHG, the IDET pin
can be connected directly to the PROG pin. This reduces
the component count, as shown in Figure 6.
Power Dissipation
When designing the battery charger circuit, it is not neces-
sary to design for worst-case power dissipation scenarios
because the LTC4061 automatically reduces the charge
current during high power conditions. The conditions
that cause the LTC4061 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:
PD = (VCC – VBAT) • IBAT
PD is the power dissipated, VCC is the input supply voltage,
VBAT is the battery voltage and IBAT is the charge current.
The approximate ambient temperature at which the thermal
feedback begins to protect the IC is:
TA = 105°C – PD • θJA
TA = 105°C – (VCC – VBAT) • IBAT • θJA
Example: An LTC4061 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
θJA is 40°C/W (see Thermal Considerations), the ambient
temperature at which the LTC4061 will begin to reduce the
charge current is approximately:
TA = 105°C – (5V – 3.3V) • (800mA) • 40°C/W
TA = 105°C – 1.36W • 40°C/W = 105°C – 54.4°C
TA = 50.6°C
The LTC4061 can be used above 50.6°C ambient, but
the charge current will be reduced from 800mA. The ap-
proximate current at a given ambient temperature can be
approximated by:
IC T
V V
BAT A
CC BAT JA
=°105 –
( – ) • θ
Using the previous example with an ambient tem-
perature of 60°C, the charge current will be reduced to
approximately:
IC C
V V C W
C
C A
I
BAT
BAT
=° °
°=°
°
=
105 60
5 3 3 40
45
68
–
( – . ) • / /
6662mA
When PROG and IDET are connected in this way, the full-
scale charge current, ICHG, 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 reduces
the maximum allowed program resistor value.
+
VCC
PROG
IDET
VIN BAT
500mA
TIMER
RDET
2k
RPROG
2k
LTC4061
GND
+
VCC
PROG
IDET
VIN
4061 F06
BAT
500mA
TIMER
RPROG
1k
LTC4061
GND
C/5
C/5
Figure 6. Two Circuits That Charge at 500mA
Full-Scale Current and Terminate at 50mA
LTc4061
3.266
LTC4061
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It is important to remember that LTC4061 applications do
not need to be designed for worst-case thermal conditions,
since the IC will automatically reduce power dissipation if
the junction temperature reaches approximately 105°C.
Thermistors
The LTC4061 NTC comparator trip points were designed
to work with thermistors whose resistance-temperature
characteristics follow Vishay Dale’s “R-T Curve 1.” The
Vishay NTHS0603N01N1003J is an example of such a
thermistor. However, Vishay Dale has many thermistor
products that follow the “R-T Curve 1” characteristic in a
variety of sizes. Furthermore, any thermistor whose ratio
of RCOLD to RHOT is about 6 also works (Vishay Dale R-T
Curve 1 shows a ratio of RCOLD to RHOT of 3.266/0.5325
= 6.13).
Power conscious designers may want to use thermistors
whose room temperature value is greater than 10kΩ.
Vishay Dale has a number of values of thermistor from
10kΩ to 100kΩ that follow the “R-T Curve 1.” Using dif-
ferent R-T curves, such as Vishay Dale “R-T Curve 2,” is
also possible. This curve, combined with LTC4061 internal
thresholds, gives temperature trip points of approximately
0°C (falling) and 40°C (rising), a delta of 40°C. This delta in
temperature can be moved in either direction by changing
the value of RNOM with respect to RNTC. Increasing RNOM
moves both trip points to lower temperatures. Likewise
a decrease in RNOM with respect to RNTC moves the trip
points to higher temperatures. To calculate RNOM for a shift
to lower temperatures, use the following equation:
RRR at C
NOM COLD NTC
= °
3 266 25
.•
where RCOLD is the resistance ratio of RNTC at the desired
cold temperature trip point. If you want to shift the trip points
to higher temperatures, use the following equations:
RRR at C
NOM HOT NTC
= °
0 5325 25
.•
where RHOT is the resistance ratio of RNTC at the desired
hot temperature trip point.
Here is an example using 10kΩ R-T Curve 2 thermistor
from Vishay Dale. The difference between the trip points
applicaTions inForMaTion
is 40°C, from before, and we want the cold trip point to
be 0°C, which would put the hot trip point at 40°C. The
RNOM needed is calculated as follows:
RRR at C
k
NOM COLD NTC
= °
= =
3 266 25
2 816
3 266 10 8 62
.•
.
.• .ΩkkΩ
The nearest 1% value for RNOM is 8.66kΩ. This is the
value used to bias the NTC thermistor to get cold and hot
trip points of approximately 0°C and 40°C respectively.
To extend the delta between the cold and hot trip points, a
resistor, R1, can be added in series with RNTC. The values
of the resistors are calculated as follows:
RR R
R
NOM COLD HOT
=
=
–
. – .
.
. - .
3 266 0 5325
0 5325
3 266 0 532
155
•( – ) –R R R
COLD HOT HOT
where RNOM is the value of the bias resistor, RHOT and
RCOLD are the values of RNTC at the desired temperature
trip points. Continuing the example from before with a
desired hot trip point of 50°C:
RR R k
NOM COLD HOT
= =
–
. – .
•( . – . )
3 266 0 5325
10 2 816 0 4086
3.. – .
. , . % .
266 0 5325
8 8 8 87 1=k k is the nearest valueΩ
R k
110 0 5325
3 266 0 5325
2 816 0 4086
=
•.
. – .
• ( . – . ) – 00 4086
604 604 1
.
, % .= Ω is the nearest value
The final solution is RNOM = 8.87kΩ, R1 = 604Ω and
RNTC = 10kΩ at 25°C.
NTC Trip Point Error
When a 1% resistor is used for RHOT, the major error
in the 40°C trip point is determined by the tolerance of
the NTC thermistor. A typical 100kΩ NTC thermistor has
±10% tolerance. By looking up the temperature coef-
ficient of the thermistor at 40°C, the tolerance error can
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be calculated in degrees centigrade. Consider the Vishay
NTHS0603N01N1003J thermistor, which has a temperature
coefficient of –4%/°C at 40°C. Dividing the tolerance by
the temperature coefficient, ±5%/(4%/°C) = ±1.25°C, gives
the temperature error of the hot trip point.
The cold trip point error depends on the tolerance of the
NTC thermistor and the degree to which the ratio of its
value at 0°C and its value at 40°C varies from 6.14 to 1.
Therefore, the cold trip point error can be calculated us-
ing the tolerance, TOL, the temperature coefficient of the
thermistor at 0°C, TC (in %/°C), the value of the thermistor
at 0°C, RCOLD, and the value of the thermistor at 40°C,
RHOT. The formula is:
Temperature Error C
TOL R
R
COLD
HOT
( ) .• –
° =
+
1
6 14 1
• 100
TC
For example, the Vishay NTHS0603N01N1003J thermistor
with a tolerance of ±5%, TC of -5%/°C and RCOLD/ RHOT
of 6.13, has a cold trip point error of:
Temperature Error C( )
.
.• . – •
° =
+
1 0 05
6 14 6 13 1 1000
5
0 95 1 05
–
– . , .= ° °C 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 LTC4061 package is properly soldered to
the PC board ground. Correctly soldered to a 2500mm2
double sided 1oz copper board, the LTC4061 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 LTC4061 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.
VCC Bypass Capacitor
Many types of capacitors can be used for input bypassing;
however, caution must be exercised when using multilayer
ceramic capacitors. Because of the self-resonant and high
Q characteristics of some types of ceramic capacitors, 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 LTC4061 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
voltage on VCC 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).
USB and Wall Adapter Power
The LTC4061 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
VCC
VIN
4061 F07
LTC4061
DRAIN-BULK
DIODE OF FET
Figure 7. Low Loss Input Reverse Polarity Protection
LTC406 1
5v WALL
T
A
g,
,HL
L
NOTE
I DRAWING TO BE MADE A
CHECK THE LTD WEBSLTE
2 DRAme NOT m SCALE
3 ALL DLMENSLDNS ARE IN MLLLIMEI
a DLMENSIDMS 0F EXPOSED PAD Du
MOLDELASH MDLDFLASHJFPR
5 EXPOSED PAD SHALL BE SDLDER
5 SHADED AREA IS DNLV A REFER
TOP AND EDWDM DF PACKAGE
LTC4061
18
4061fd
package DescripTion
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.
+
VCC
D1
PROG
IDET
3.3k
2k
MN1
5V WALL
ADAPTER
ICHG = 800mA
USB POWER
ICHG = 500mA MP1
4061 F08
BAT
LTC4061
1.25k
Li-Ion
BATTERY
SYSTEM
LOAD
1k
C/5
Figure 8. Combining Wall Adapter and USB Power
3.00 p0.10
(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
0.40 p 0.10
BOTTOM VIEW—EXPOSED PAD
1.65 p 0.10
(2 SIDES)
0.75 p0.05
R = 0.125
TYP
2.38 p0.10
(2 SIDES)
15
106
PIN 1
TOP MARK
(SEE NOTE 6)
0.200 REF
0.00 – 0.05
(DD) DFN REV C 0310
0.25 p 0.05
2.38 p0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
1.65 p0.05
(2 SIDES)2.15 p0.05
0.50
BSC
0.70 p0.05
3.55 p0.05
PACKAGE
OUTLINE
0.25 p 0.05
0.50 BSC
PIN 1 NOTCH
R = 0.20 OR
0.35 s 45o
CHAMFER
DD Package
10-Lead Plastic DFN (3mm × 3mm)
(Reference LTC DWG # 05-08-1699 Rev C)
LTCAOé 1
L7 LJUW
19
LTC4061
19
4061fd
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
revision hisTory
REV DATE DESCRIPTION PAGE NUMBER
D 7/10 Updated Charge Time Termination equation 11
(Revision history begins at Rev D)
LTC406 1
m C: Li
20 L7ELUEN2
LTC4061
20
4061fd
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2005
LT 0710 REV D • PRINTED IN USA
relaTeD parTs
Typical applicaTion
USB/Wall Adapter Power Li-Ion Charger
(Using Charge Current Termination)
Full-Featured Li-Ion Charger
(Using Time Termination)
PART NUMBER DESCRIPTION COMMENTS
Battery Chargers
LTC1734 Lithium-Ion Linear Battery Charger in ThinSOT™ Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed
LTC1734L Lithium-Ion Linear Battery Charger in ThinSOT Low Current Version of LTC1734, 50mA ≤ ICHRG ≤ 0mA
LTC4002 Switch Mode Lithium-Ion Battery Charger Standalone, 4.7V ≤ VIN ≤ 24V, 500kHz Frequency, 3 Hour Charge Termination
LTC4052 Monolithic Lithium-Ion Battery Pulse Charger No Blocking Diode or External Power FET Required, ≤1.5A Charge Current
LTC4053 USB Compatible Monolithic Li-Ion Battery
Charger
Standalone Charger with Programmable Timer, Up to 1.25A Charge Current
LTC4054 Standalone Linear Li-Ion Battery Charger with
Integrated Pass Transistor in ThinSOT
Thermal Regulation Prevents Overheating, C/10 Termination,
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
LTC4062 Standalone Linear Li-Ion Battery Charger with
Micropower Comparator
4.2V, ±0.35% Float Voltage, Up to 1A Charge Current,
3mm × 3mm DFN Package
LTC4063 Li-Ion Charger with Linear Regulator Up to 1A Charge Current, 100mA, 125mV LDO, 3mm × 3mm DFN Package
LTC4411/LTC4412 Low Loss PowerPath™ Controller in ThinSOT Automatic Switching Between DC Sources, Load Sharing, Replaces ORing Diodes
Power Management
LTC3405/LTC3405A 300mA (IOUT), 1.5MHz, Synchronous Step-Down
DC/DC Converter
95% Efficiency, VIN: 2.7V to 6V, VOUT = 0.8V, IQ = 20µA, ISD < 1µA,
ThinSOT Package
LTC3406/LTC3406A 600mA (IOUT), 1.5MHz, Synchronous Step-Down
DC/DC Converter
95% Efficiency, VIN: 2.5V to 5.5V, VOUT = 0.6V, IQ = 20µA, ISD < 1µA,
ThinSOT Package
LTC3411 1.25A (IOUT), 4MHz, Synchronous Step-Down
DC/DC Converter
95% Efficiency, VIN: 2.5V to 5.5V, VOUT = 0.8V, IQ = 60µA, ISD < 1µA,
MS Package
LTC3440 600mA (IOUT), 2MHz, Synchronous Buck-Boost
DC/DC Converter
95% Efficiency, VIN: 2.5V to 5.5V, VOUT = 2.5V, IQ = 25µA, ISD < 1µA,
MS Package
LTC4413 Dual Ideal Diode in DFN 2-Channel Ideal Diode ORing, Low Forward On-Resistance, Low Regulated
Forward Voltage, 2.5V ≤ VIN ≤ 5.5V
+
CHRG
TIMER
PROG
IDET
5
3
9
8
BAT
ACPR
NTC
1
2
LTC4061
GND
100k
100k
NTC
11
619Ω
1.25k
1k 1k
800mA
10
1µF
0.1µF
VIN
5V
4061 TA02
VIN
SINGLE-CELL
Li-Ion BATTERY
VCC
6
4
C/5
+
VCC
TIMER
BAT
PROG
IDET
LTC4061
GND 2k1k 11
8
9
1
1µF
10
3
6
2.5k
USB
POWER
4061 TA03
Li-Ion
CELL
µC C/5
5V
WALL ADAPTER
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