LTC4054 [Linear]
Standalone Linear Li-lon Battery Charger with Thermistor Input; 独立线性的锂离子电池充电器，热敏电阻输入
| 型号： | LTC4054 |
| 厂家： | 
Linear |
| 描述： | Standalone Linear Li-lon Battery Charger with Thermistor Input |
| 文件： | 总20页 (文件大小：665K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC4061
Standalone Linear Li-Ion Battery
Charger with Thermistor Input
U
FEATURES
DESCRIPTIO
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.
■
Charge Current Programmable up to 1A
■
Charges Single Cell Li-Ion Batteries Directly from
USB Port
■
Preset Charge Voltage with ±±0.35 Accuracy
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 bat-
tery temperature sensing and the SmartStartTM charging
algorithm.
■
Thermistor Input for Temperature Qualified
Charging
Input Supply Present Logic Output
■
■
Thermal Regulation Maximizes Charge Rate
Without Risk of Overheating*
■
Programmable Charge Current Detection/
Termination
■
Programmable Charge Termination Timer
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 2µA.
■
Smart Pulsing Error Feature
SmartStartTM Prolongs Battery Life
■
■
20µA Charger Quiescent Current in Shutdown
■
Available in a Low Profile (0.75mm) 10-Lead
(3mm × 3mm) DFN Package
U
APPLICATIO S
■
Handheld Computers
■
Portable MP3 Players
Other features include smart recharge, USB C/5 cur-
rent programming input, undervoltage lockout and AC
Present logic.
■
Digital Cameras
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
SmartStart is a trademark of Linear Technology Corporation.
*Protected by U.S. Patents including 6522118.
U
Complete Charge Cycle (11±±mAh Battery)
TYPICAL APPLICATIO
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
8±±mA Single Cell Li-Ion Battery Charger
(C/1± Termination)
800mA
V
IN
V
BAT
CC
4.3V TO 8V
LTC4061
EN
1µF
CHRG
ACPR
NTC
C/5
BATTERY
CURRENT
BATTERY
VOLTAGE
4.2V
SINGLE CELL
Li-Ion BATTERY
+
TIMER
PROG
I
DET
GND
V
A
= 5V
CC
619Ω
T
= 25°C
4061 TA01a
0
0.5
1.0
1.5
2.0
2.5
3.0
TIME (HOURS)
4061 TA01b
4061fa
1
LTC4061
W W U W
U
W
U
ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
(Note 1)
ORDER PART
Input Supply Voltage (V )........................–0.3V to 10V
TOP VIEW
CC
NUMBER
EN, ACPR, CHRG, NTC, PROG,
BAT
NTC
1
2
3
4
5
10
9
V
CC
C/5, BAT.....................................................–0.3V to 10V
PROG
LTC4061EDD
TIMER, I
.................................... –0.3V to V + 0.3V
TIMER
ACPR
CHRG
11
8
I
DET
CC
DET
7
EN
BAT Short-Circuit Duration............................Continuous
Pin Current...........................................................1A
6
C/5
V
DD PART
MARKING
CC
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
T
= 125°C, θ = 40°C/W (NOTE 3)
JA
EXPOSED PAD IS GROUND (PIN 11)
MUST BE SOLDERED TO PCB
JMAX
LBJS
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 23°C0 VCC = 3V, unless otherwise noted0
SYMBOL
VCC
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Supply Voltage
Input Supply Current
●
4.3
8
V
ICC
Charge Mode (Note 4), RPROG = 10k
Standby Mode, Charge Terminated
Shutdown (EN = 5V, VCC < VBAT or VCC < VUV
●
●
●
240
130
20
500
300
50
µA
µA
µA
)
VFLOAT
IBAT
VBAT Regulated Output Voltage
BAT Pin Current
4.185
4.175
4.2
4.2
4.215
4.225
V
V
0 ≤ T ≤ 85°C
A
RPROG = 10k, Constant Current Mode
●
●
●
●
93
760
100
800
1
107
840
2
mA
mA
µA
R
PROG = 1.25k, Constant Current Mode
Standby Mode, Charge Terminated
Shutdown Mode
1
2
µA
VPROG
PROG Pin Voltage
RPROG = 10k, Constant Current Mode
0.97
0.97
1
1
1.03
1.03
V
V
R
PROG = 1.25k, Constant Current Mode
VACPR
VCHRG
ITRIKL
ACPR Output Low Voltage
CHRG Output Low Voltage
Trickle Charge Current
IACPR = 5mA
0.1
0.1
0.25
0.25
V
V
ICHRG = 5mA
VBAT < VTRIKL, RPROG = 10k
6
60
10
80
14
100
mA
mA
V
BAT < VTRIKL, RPROG = 1.25k
VTRIKL
VUV
Trickle Charge Threshold Voltage
VCC Undervoltage Lockout Voltage
VCC – VBAT Lockout Threshold Voltage
VBAT Rising
Hysteresis
2.8
2.9
100
3
V
mV
From Low to High
Hysteresis
3.7
3.8
200
3.9
V
mV
VASD
VCC from Low to High, V = 4.3V
VCC from High to Low, V = 4.3V
145
10
190
45
230
75
mV
mV
BAT
BAT
REN
VEN
EN Pin Pull-Down Resistor
EN Input Threshold Voltage
●
2
3.4
5
1
MΩ
EN Rising, 4.3V < VCC < 8V
Hysteresis
0.4
0.7
70
V
mV
VCT
Charge Termination Mode Threshold
Voltage
VTIMER from High to Low
Hysteresis
0.4
0.7
50
1
V
mV
4061fa
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LTC4061
The ● denotes the specifications which apply over the full operating
ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifications are at TA = 23°C0 VCC = 3V, unless otherwise noted0
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
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 ≤ T ≤ 85°C
90
45
8
100
50
10
5
110
55
12
mA
mA
mA
mA
A
RDET = 2k, 0 ≤ T ≤ 85°C
A
RDET = 10k, 0 ≤ T ≤ 85°C
A
RDET = 20k, 0 ≤ T ≤ 85°C
3.8
6.2
A
ΔVRECHRG
tSS
Recharge Threshold Voltage
Soft-Start Time
VFLOAT – VRECHRG, 0 ≤ T ≤ 85°C
65
100
100
1.5
7
135
mV
µs
A
IBAT from 0 to ICHRG
tTERM
tRECHRG
tTIMER
RC/5
Termination Comparator Filter Time
Recharge Comparator Filter Time
Charge Cycle Time
Current Termination Mode
0.8
3
2.5
14
3.45
5
ms
ms
hr
CTIMER = 0.1µF
2.55
2
3
C/5 Pin Pull-Down Resistor
C/5 Input Threshold Voltage
●
3.4
MΩ
VC/5
C/5 Rising, 4.3V < VCC < 8V
Hysteresis
0.4
0.7
70
1
V
mV
VNTC-HOT
VNTC-COLD
VNTC-DIS
NTC Pin Hot Threshold Voltage
NTC Pin Cold Threshold Voltage
NTC Pin Disable Threshold Voltage
NTC Fault Pulsing Frequency
VNTC Falling
0.35 • VCC
0.36 • VCC
V
V
V
NTC Rising
VNTC Rising
NTC Falling
0.76 • VCC
0.75 • VCC
V
V
V
VNTC Falling
Hysteresis
70
1
85
50
100
2
mV
mV
f
Current/User Termination Mode
Time Termination Mode C
1.5
1.5
Hz
Hz
CHRG
= 0.1µF
TIMER
TLIM
RON
Junction Temperature in Constant
Temperature Mode
105
°C
Power FET “ON” Resistance
VBAT = 3.85V, ICC = 175mA, RPROG = 2k
375
mΩ
(Between V and BAT)
CC
Note 1: Absolute Maximum Ratings are those values beyond which the life
of the device may be impaired.
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 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 3: 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.
Note .: 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.
4061fa
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LTC4061
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TYPICAL PERFOR A CE CHARACTERISTICS
Battery Regulated Output (Float)
Voltage vs Charge Current
Battery Regulated Output (Float)
Voltage vs Temperature
Battery Regulated Output (Float)
Voltage vs Supply Voltage
4.26
4.24
4.22
4.20
4.18
4.16
4.14
4.12
4.10
4.215
4.210
4.205
4.200
4.195
4.190
4.185
4.26
4.24
4.22
4.20
4.18
4.16
4.14
4.12
4.10
V
= 5V
PROG
V
= 5V
CC
PROG
R
T
BAT
= 1k
CC
R
PROG
A
= 1k
R
= 10k
= 25°C
I
= 10mA
6.0 6.5
(V)
4.0 4.5 5.0 5.5
7.0 7.5 8.0
200
400
800
–50
0
25
50
75
100
0
1000
–25
600
TEMPERATURE (°C)
V
CHARGE CURRENT (mA)
CC
4061 G03
4061 G02
4061 G01
Charge Current vs PROG Pin
Voltage
PROG Pin Voltage vs Temperature
(Constant-Current Mode)
PROG Pin Voltage vs VCC
(Constant-Current Mode)
1200
1.006
1.004
1.002
1.000
0.998
0.996
0.994
1.006
1.004
1.002
1.000
0.998
0.996
0.994
V
= 5V
PROG
V
V
= 5V
= 4V
PROG
R
= 10k
CC
CC
CC
BAT
R
PROG
C/5 = V
R
= 1k
1000 C/5 = 5V
= 5V
= 10k
V
C/5 = 5V
TIMER
800
600
400
200
0
V
= 8V
CC
V
CC
= 4.3V
0
0.4
0.6
0.8
1.0
1.2
0.2
4.0 4.5
5.5 6.0 6.5 7.0
(V)
8.0
5.0
7.5
–50
0
25
50
75
100
–25
V
PROG
(V)
V
TEMPERATURE (°C)
CC
4061 G04
4061 G06
4061 G05
Trickle Charge Current vs
Temperature
Trickle Charge Threshold Voltage
vs Temperature
Charge Current vs Battery Voltage
2.96
2.94
2.92
2.90
2.88
2.86
2.84
550
450
350
250
150
50
84
82
80
78
76
V
V
= 5V
V
= 5V
CC
PROG
CC
= 2.5V
R
= 1.25k
BAT
PROG
C/5 = 5V
R
= 1.25k
V
= 5V
PROG
CC
R
= 2k
C/5 = 0V
3.0
3.2
–50
0
25
50
75
100
–50
0
25
50
75
100
3.4
V
3.6
(V)
3.8
4.0
–25
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
BAT
4061 G08
4061 G07
4061 G09
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LTC4061
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TYPICAL PERFOR A CE CHARACTERISTICS
NTC Fault Pulsing Frequency
vs VCC
NTC Fault Pulsing Frequency
vs Temperature
Internal Charge Timer vs
Temperature
195
190
185
180
175
170
165
1.7
1.6
1.5
1.4
1.3
1.2
1.60
1.55
1.50
1.45
1.40
1.35
1.30
C
= 0.1µF
C
= 0.1µF
TIMER
TIMER
V
= 4.3V
= 8V
CC
V
= 8V
CC
V
CC
V
CC
= 4.3V
C
= 0.1µF
TIMER
–50
0
25
50
75
100
–50
0
25
50
75
100
–25
–25
4.0
4.5
5.5 6.0 6.5 7.0
(V)
8.0
5.0
7.5
TEMPERATURE (°C)
TEMPERATURE (°C)
V
CC
4061 G10
4061 G12
4061 G11
Charge Current vs Ambient
Temperature with Thermal
Regulation
Recharge Threshold Voltage vs
Temperature
Charge Current vs Supply Voltage
4.16
4.14
4.12
4.10
4.08
4.06
4.04
1000
800
600
400
200
0
104
102
100
98
V
V
= 5V
CC
ONSET OF THERMAL
REGULATION
= 4V
BAT
C/5 = 5V
R
= 10k
PROG
R
PROG
= 1.25k
V
CC
= 8V
R
PROG
= 2k
V
CC
= 4.3V
96
–50
0
25
50
75
100
–25
50
75 100 125
4.0
4.5
5.0
5.5 6.0 6.5 7.0
(V)
7.5
8.0
–50 –25
0
25
TEMPERATURE (°C)
TEMPERATURE (°C)
V
CC
4061 G15
4061 G13
4061 G14
Power FET “ON” Resistance vs
Temperature
Undervoltage Lockout Voltage vs
Temperature
Charge Current vs Battery Voltage
500
450
400
350
300
250
900
800
700
600
500
400
300
200
100
0
3.900
3.875
3.850
3.825
3.800
3.775
3.750
3.725
3.700
V
BAT
= 4V
CC
I
= 200mA
–50
0
25
50
75
100
–25
4.0
4.5
0
0.5
1.5 2.0 2.5 3.5
3.0
50
TEMPERATURE (°C)
100
1.0
–50 –25
0
25
75
TEMPERATURE (°C)
V
BAT
(V)
4061 G16
4061 G18
4061 G17
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LTC4061
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TYPICAL PERFOR A CE CHARACTERISTICS
EN Pin Pulldown Resistance vs
Temperature
C/3 Pin Pulldown Resistance vs
Temperature
EN Pin Threshold Voltage
(On-to-Off) vs Temperature
4.0
3.5
3.0
2.5
2.0
1.5
4.0
3.5
3.0
2.5
2.0
1.5
900
850
800
750
700
650
600
V
= 5V
CC
50
TEMPERATURE (°C)
100
50
TEMPERATURE (°C)
100
–50
–25
0
25
75
–50 –25
0
25
75
–50
0
25
50
75
100
–25
TEMPERATURE (°C)
4061 G19
4061 G21
4061 G20
C/3 Pin Threshold Voltage
(High-to-Low) vs Temperature
Shutdown Supply Current vs
Temperature and VCC
ACPR Pin I-V Curve
70
60
50
40
30
20
10
160
140
120
100
80
900
850
800
750
700
V
V
= 5V
BAT
CC
V
= 5V
EN = V
CC
CC
= 4V
T
= –40°C
A
T
= 25°C
A
T
= 90°C
A
V
= 8V
CC
60
40
V
= 5V
CC
650
600
20
V
CC
= 4.3V
0
–50
0
25
50
75
100
2
50
TEMPERATURE (°C)
100
–25
0
3
4
–50 –25
0
25
75
1
TEMPERATURE (°C)
V
(V)
ACPR
4061 G23
4061 G24
4061 G22
CHRG Pin Output Low Voltage vs
Temperature
ACPR Pin Output Low Voltage vs
Temperature
CHRG Pin I-V Curve
0.6
0.5
0.4
0.3
0.2
0.1
0
160
140
120
100
80
0.6
0.5
0.4
0.3
0.2
0.1
0
V
V
= 5V
= 4V
V
I
= 5V
CHRG
V
I
= 5V
CC
ACPR
CC
BAT
CC
= 5mA
= 5mA
T
= –40°C
A
T
= 25°C
A
T
= 90°C
A
60
40
20
0
50
TEMPERATURE (°C)
100
–50 –25
0
25
75
50
TEMPERATURE (°C)
100
0
1
2
3
4
–50
–25
0
25
75
V
CHRG
(V)
4061 G25
4061 G26
4061 G27
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LTC4061
U
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PI FU CTIO S
BAT (Pin 1): Charge Current Output. This pin provides pulse at 1.5Hz or 6Hz and high impedance. This output
charge current to the battery and regulates the final float can be used as a logic interface or as a LED driver. In the
voltage to 4.2V.
pull-down state, an NMOS transistor capable of sinking
10mA pulls down on the CHRG pin. The state of this pin
NTC(Pin2):InputtotheNTC(NegativeTemperatureCoef-
ficient)ThermistorTemperatureMonitoringCircuit.Under
normal operation, connect a thermistor from the NTC pin
to ground and a resistor of equal value from the NTC pin
depends on the value of I
as well as the termina-
DETECT
tion method being used and the state of the NTC pin. See
Applications Information.
to V . When the voltage at this pin drops below 0.35 • C/3 (Pin 6): C/5 Enable Input. Used to control the amount
CC
V
CC
at hot temperatures or rises above 0.76 • V at cold, of current drawn from the USB port. A logic high on the
CC
charging is suspended, the internal timer is frozen and the C/5 pin sets the current limit to 100% of the current
CHRG pin output will start to pulse at 1.5Hz. Pulling this programmed by the PROG pin. A logic low on the C/5 pin
pin below 0.016 • V disables the NTC feature. There is sets the current limit to 20% of the current programmed
CC
approximately 2°C of temperature hysteresis associated by the PROG pin. An internal 3MΩ pull-down resistor
with each of the input comparators thresholds.
defaults the C/5 pin to its low current state.
TIMER(Pin.):TimerProgramandTerminationSelectPin. EN(Pin7):ChargerEnableInput.AlogichighontheENpin
This pin selects which method is used to terminate the places the charger into shutdown mode, where the input
charge cycle. Connecting a capacitor, C
, to ground quiescent current is less than 50µA. A logic low on this
TIMER
selects charge time termination. The charge time is set pin enables charging. An internal 3MΩ pull-down resistor
by the following formula:
to ground defaults the charger to its enabled state.
I
(Pin 8): Current Detection Threshold Program Pin.
DET
CTIMER
0.1µF
TIME (HOURS)
3 (HOURS)
TIME (HOURS) = 3 HOURS •
or
The current detection threshold, I
, is set by con-
DETECT
necting a resistor, R
the following formula:
, to ground. I
is set by
DETECT
DETECT
CTIMER = 0.1µF •
RPROG
10RDET
100V
RDET
IDETECT
=
•ICHG
=
or
Connecting the TIMER pin to ground selects charge cur-
rent termination, while connecting the pin to V selects
CC
100V
IDETECT
user termination. See Applications Information for more
RDET
=
information on current and user termination.
ACPR (Pin 4):
Open-Drain Power Supply Present Status The CHRG pin becomes high impedance when the charge
Output. The power supply status indicator pin has two current drops below I . I can be set to 1/10th
DETECT DETECT
states: pull-down and high impedance. This output can the programmed charge current by connecting I
di-
DET
be used as a logic interface or as a LED driver. In the rectly to PROG. If the I
pin is not connected, the CHRG
DET
pull-down state, an NMOS transistor capable of sinking output remains in its pull-down state until the charge time
10mA pulls down on the ACPR pin. The state of this pin elapses and terminates the charge cycle. See Applications
is dependent on the value of V and BAT: it requires that Information.
CC
BAT
V
is 190mV greater than V
and greater than V
.
CC
UVLO
Thispinisclampedtoapproximately2.4V.Drivingthispinto
voltages beyond the clamp voltage should be avoided.
See Applications Information.
CHRG (Pin 3): Open-Drain Charge Status Output. The
charge status indicator pin has three states: pull-down,
PROG (Pin 9): Charge Current Program and Charge Cur-
rent Monitor. The charge current is set by connecting a
4061fa
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LTC4061
U
U
U
PI FU CTIO S
V
(Pin 1±): Positive Input Supply Voltage. Provides
resistor, R
, to ground. When charging in constant
CC
PROG
power to the battery charger. This pin should be bypassed
with a 1µF capacitor.
current mode, this pin servos to 1V. The voltage on this
pin can be used to measure the charge current using the
following formula:
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.
VPROG
RPROG
IBAT
=
•1000
W
BLOCK DIAGRA
10
V
CC
+
–
4.1V
C1
1×
TO BAT
1×
1000×
BAT
1
NTC
2
4
–
+
MA
ACPR
CHRG
HOT COLD DIS
ACPR
CA
VA
+
+
–
–
5
1V
0.2V
0.1V
1.2V
STOP
RECHRG
C/5
C/5
6
7
LOGIC
3M
LOGIC
EN
EN
I
DETECT
C/5
3M
SEL
C2
C3
+
+
–
–
COUNTER
0.1V
TO BAT
2.9V
T
+
DIE
OSCILLATOR
T
A
105°C
–
SHDN
TIMER
3
I
PROG
GND
11
DET
8
9
4061 BD
C
R
DET
R
PROG
TIMER
4061fa
8
LTC4061
U
OPERATIO
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
externalsenseresistorisrequired;thus, thebasiccharger
circuit requires only two external components.
1000V
ICHG
1000V
RPROG
RPROG
=
,ICHG =
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:
VPROG
RPROG
IBAT
=
•1000
Normal Operation
SmartStart
The charge cycle begins when the voltage at the V pin
CC
When the LTC4061 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(whichcorrespondstoapproximately80-90%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
featurereducesthenumberofunnecessarychargecycles,
prolonging battery life.
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.
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.
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.GroundingtheTIMERpinandconnectingaresis-
tor to the I
pin causes the charge cycle to terminate
DET
once the charge current falls below a set threshold when
the charger is in constant voltage mode. Connecting the
TIMER pin to V disables internal termination, allowing
Thermal Regulation
CC
external charge user termination through the EN input.
See Applications Information for more information on
charge termination methods.
Aninternalthermalfeedbackloopreducestheprogrammed
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
capabilityofagivencircuitboardwithoutriskofdamaging
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.
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:
4061fa
9
LTC4061
U
OPERATIO
Undervoltage Lockout (UVLO)
capableofsinkingupto10mA.Apull-downstateindicates
that the LTC4061 is charging a battery and the charge cur-
An internal undervoltage lockout circuit monitors the
input voltage and keeps the charger in shutdown mode
rent is greater than I
(which is set by the external
DETECT
component R ). A high impedance state indicates that
DET
until V rises above the undervoltage lockout threshold
CC
the charge current has dropped below I
. In the
DET
DETECT
(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
case where the I
pin is left unconnected (R
= ∞,
DET
I
= 0), a high impedance state on CHRG indicates
DETECT
that the LTC4061 is not charging.
in shutdown mode if V falls to less than 45mV above
CC
the battery voltage. Hysteresis of 145mV prevents the
charger from cycling in and out of shutdown.
Smart Pulsing Error Feature
LTC4061 has two different pulsing states at CHRG pull-
down pin:
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.
1) 6Hz (50% duty cycle) due to defective battery detec-
tion (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.
If shutdown is not required, leaving the pin disconnected
continuously enables the circuit.
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
Trickle-Charge and Defective Battery Detection
When the BAT pin voltage is below the 2.9V trickle charge
threshold(V ),thechargerreducesthechargecurrent Figure 1. To use this feature, connect the NTC thermistor,
TRIKL
to 10% of the programmed value. If the battery remains in
trickle charge for more than 25% of the total programmed
chargetime,thechargerstopschargingandentersaFAULT
state,indicatingthatthebatteryisdefective1.TheLTC4061
indicates the FAULT state by driving the CHRG open-drain
outputwithasquarewave.Thedutycycleofthisoscillation
R
NOM
, between the NTC pin and ground and a resistor,
NTC
R
, from the NTC pin to V . R
should be a 1%
CC NOM
resistor with a value equal to the value of the chosen
NTC thermistor at 25°C (this value is 100kΩ for a Vishay
NTHS0603N01N1003J thermistor). The LTC4061 goes
into hold mode when the resistance, R , of the NTC
HOT
thermistor drops to 0.53 times the value of R
or ap-
is 50% and the frequency is set by C
:
NOM
TIMER
proximately 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 tem-
perature. As the temperature drops, the resistance of the
NTC thermistor rises. The LTC4061 is designed to go into
holdmodewhenthevalueoftheNTCthermistorincreases
0.1µF
CTIMER
fCHRG
=
•6Hz
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
to 3.26 times the value of R
. This resistance is R
.
COLD
NOM
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.
GroundingtheNTCpindisablestheNTCfunction.Formore
details refer to the Application Information section.
reapplying power to V .
CC
Charge Status Output (CHRG)
Thechargestatusindicatorpinhasthreestates:pull-down,
pulseat1.5Hzor6Hzandhighimpedance.Inthepull-down
state, an NMOS transistor pulls down on the CHRG pin
1
The Defective Battery Detection feature is only available when time termination is being used.
4061fa
10
LTC4061
U
OPERATIO
0.76 • V
0.35 • V
–
+
CC
V
CC
TOO COLD
TOO HOT
ENABLE
R
NOM
NTC
2
+
–
CC
R
NTC
+
–
0.016 • V
CC
LTC4061
4061 F01
Figure 10 NTC Circuit Information
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APPLICATIO S I FOR ATIO
Programming Charge Termination
Charge Time 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 termina-
tion methods and their behaviors.
Connecting a capacitor (C
) to the TIMER pin enables
TIMER
the timer and selects charge time termination. The total
charge time is set by:
0.1µF
CTIMER
TIME (HOURS) =
•3 HOURS
Table 10
METHOD
Charge
Time
Termination
Mode
TIMER
0.1µF to
GND
I
CHARGER DESCRIPTION
to Charges for 3 Hours. After 3 Hours, the Charger Pull-Down State While I
CHRG OUTPUT DESCRIPTION
> I . High Impedance
DET
R
DET
GND
BAT DET
Stops Charging and Enters Standby Mode.
Recharge Cycles Last for 1.5 Hours.
State While I
< I
or When Charging Is Stopped.
BAT DETECT
Pulsing State Available When NTC Is Used and
Is Still Charging.
0.1µF to
GND
NC
Charges for 3 Hours. After 3 Hours, the Charger Pull-Down State When Charging. High Impedance State
Stops Charging and Enters Standby Mode.
Recharge Cycles Last for 1.5 Hours.
When Charging Is Stopped. Pulsing State Available
When NTC Is Used and Is Still Charging.
Charge
Current
Termination
GND
GND
R
R
to Charges Until Charge Current Drops Below
Pull-Down State When Charging. High Impedance State
When Charging Is Stopped. Pulsing State Available
When NTC Is Used and Is Still Charging.
DET
GND
I
, Then Enters Standby Mode.
DET
Pull-Down State When Charging. High Impedance State
When Charging Is Stopped. Pulsing State Available
When NTC Is Used and Is Still Charging.
NC
Charges Indefinitely.
Pull-Down State While I
> I
. High Impedance
User
Selectable
Charge
BAT DETECT
V
to
Charges Indefinitely.
CC
DET
State While I
< I
or When Charging Is Stopped.
BAT DETECT
GND
SmartStart Is Disabled.
Pulsing State Available When NTC Is Used and
Is Still Charging.
Termination
V
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.
CC
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11
LTC4061
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APPLICATIO S I FOR ATIO
When the programmed time has elapsed, the charge
cycle terminates and the charger enters standby mode.
Subsequent recharge cycles terminate when 50% of the
1.5hours.Figure3describestheoperationoftheLTC4061
charger when charge time termination is used.
Charge Current Termination
programmed time has elapsed. The I
pin determines
DET
the behavior of the CHRG output. Connecting a resistor
Connecting the TIMER pin to ground selects charge cur-
rent termination. With this method, the timer is disabled
(R ) from the I
pin to ground sets the charge current
DETECT
DET
DET
detection threshold, I
:
and a resistor (R ) must be connected from the I
DET
DET
pin to ground. I
is programmed using the same
DETECT
RPROG
10RDET
100V
RDET
equation stated in the previous section. The charge cycle
terminates when the charge current falls below I
IDETECT
=
•ICHG
=
or
.
DETECT
100V
IDETECT
This condition is detected using an internal filtered
comparator to monitor the I pin. When the I pin
RDET
=
DET
DET
falls below 100mV for longer than t
(typically 1ms),
TERM
When the charge current (I ) is greater than
BAT
charging is terminated.
I
, the CHRG output is in its pull-down state. When
DETECT
When charging, transient loads on the BAT pin can cause
the I pin to fall below 100mV for short periods of time
the charger enters constant voltage mode operation and
the charge current falls below I , the CHRG output
DET
DETECT
before the DC current has dropped below the I
DETECT
) on the internal
becomes high impedance, indicating that the battery is
threshold. The 1.5ms filter time (t
TERM
almost fully charged. The CHRG output will also become
comparator ensures that transient loads of this nature do
notresultinprematurechargecycletermination. Oncethe
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.
average charge current drops below I
, the charger
DETECT
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.
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 ), the CHRG output turns off the
DET
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
User-Selectable Charge Termination
Connecting the TIMER pin to V selects user-selectable
CC
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.
hours (as set by C
). During recharge cycles, the
TIMER
LTC4061chargesthebatteryuntiltheinternaltimerreaches
The I
pin programs the behavior of the CHRG output in
DET
500mA
the same manner as when using charge time termination.
V
IN
V
BAT
LTC4061
CC
If the I
pin is not connected, the CHRG output remains
DET
C/5
CHRG
in its pull-down state until the charger is shut down.
+
PROG TIMER
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.
I
DET
R
PROG
2k
C
TIMER
R
GND
DET
1k
0.1µF
4061 F02
Figure 20 Time Termination Mode0
The Charge Cycle Ends After . Hours0
4061fa
12
LTC4061
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APPLICATIO S I FOR ATIO
U
POWER ON
DEFECTIVE BATTERY
FAULT MODE
NO CHARGE CURRENT
CHRG STATE: PULSING
1/4 CHARGE TIME
EN = 0V
ELAPSES
OR UVLO
CONDITION
STOPS
TRICKLE CHARGE MODE
1/10TH FULL CURRENT
CHRG STATE: PULL-DOWN
BAT > 2.9V
BAT < 2.9V
SHUTDOWN MODE
DROPS TO 20µA
CHARGE MODE
I
FULL CURRENT
CC
CHRG STATE:
PULL-DOWN IF I
> I
2.9V < BAT < 4.1V
BAT DETECT
CHRG STATE: Hi-Z
Hi-Z IF I
< I
BAT DETECT
CHARGE TIME
ELAPSES
STANDBY MODE
BAT > 4.1V
NO CHARGE CURRENT
EN = 5V
OR
UVLO CONDITION
CHRG STATE: Hi-Z
BAT < 4.1V
RECHARGE MODE
FULL CURRENT
CHRG STATE:
1/2 CHARGE
TIME ELAPSES
PULL-DOWN IF I
> I
BAT DETECT
Hi-Z IF I
< I
BAT DETECT
4061 F03
Figure .0 State Diagram of a Charge Cycle
Using Charge Time Termination
4061fa
13
LTC4061
U
W U U
APPLICATIO S I FOR ATIO
POWER ON
TRICKLE CHARGE MODE
1/10TH FULL CURRENT
EN = 0V
OR UVLO
CONDITION
STOPS
CHRG STATE: PULL-DOWN
BAT > 2.9V
BAT < 2.9V
SHUTDOWN MODE
DROPS TO 20µA
CHARGE MODE
2.9V < BAT < 4.1V
I
FULL CURRENT
CC
CHRG STATE: PULL-DOWN
CHRG STATE: Hi-Z
I
< I
BAT DETECT
BAT < 4.1V
IN VOLTAGE MODE
STANDBY MODE
NO CHARGE CURRENT
CHRG STATE: Hi-Z
EN = 5V
OR
UVLO CONDITION
BAT > 4.1V
4061 F04
Figure 40 State Diagram of a Charge Cycle
Using Charge Current Termination
POWER ON
EN = 0V
OR UVLO
CONDITION
STOPS
TRICKLE CHARGE MODE
1/10TH FULL CURRENT
SHUTDOWN MODE
DROPS TO 20µA
CHRG STATE: PULL-DOWN
I
CC
BAT < 2.9V
BAT > 2.9V
CHRG STATE: Hi-Z
CHARGE MODE
FULL CURRENT
CHRG STATE:
PULL-DOWN IF I
EN = 5V
OR
UVLO CONDITION
> I
2.9V < BAT
BAT DETECT
Hi-Z IF I
< I
BAT DETECT
4061 F05
Figure 30 State Diagram of a Charge Cycle
Using User-Selectable Termination
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14
LTC4061
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APPLICATIO S I FOR ATIO
Programming C/1± Current Detection/Termination
Power Dissipation
In most cases, an external resistor, R , is needed to set
Whendesigningthebatterychargercircuit, itisnotneces-
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:
DET
the charge current detection threshold, I
. However,
DETECT
when setting I
to be 1/10th of I , the I
pin
DETECT
CHG
DET
can be connected directly to the PROG pin. This reduces
the component count, as shown in Figure 6.
500mA
V
V
BAT
LTC4061
IN
CC
C/5
+
PROG
I
TIMER
GND
DET
R
PROG
2k
R
DET
2k
P = (V – V ) • I
BAT
D
CC
BAT
P isthepowerdissipated, V istheinputsupplyvoltage,
D
CC
V
is the battery voltage and I
is the charge current.
BAT
BAT
500mA
V
V
BAT
LTC4061
Theapproximateambienttemperatureatwhichthethermal
IN
CC
C/5
feedback begins to protect the IC is:
+
PROG
T = 105°C – P • θ
JA
I
TIMER
GND
A
D
DET
R
PROG
1k
θ
T = 105°C – (V – V ) • I • JA
BAT
A
CC
BAT
4061 F06
Example: An LTC4061 operating from a 5V wall adapter
is programmed to supply 800mA full-scale current to a
dischargedLi-Ionbatterywithavoltageof3.3V.Assuming
Figure 60 Two Circuits That Charge at 3±±mA
Full-Scale Current and Terminate at 3±mA
θ
is 40°C/W (see Thermal Considerations), the ambient
JA
When PROG and I
are connected in this way, the full-
CHG
DET
temperature at which the LTC4061 will begin to reduce
the charge current is approximately:
scalechargecurrent, I , isprogrammedwithadifferent
equation:
T = 105°C – (5V – 3.3V) • (800mA) • 40°C/W
A
500V
ICHG
500V
RPROG
RPROG
=
,ICHG =
T = 105°C – 1.36W • 40°C/W = 105°C – 54.4°C
A
T = 50.6°C
A
Stability Considerations
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:
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.
105°C – TA
IBAT
=
(VCC – VBAT )•θJA
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,additionalcapacitanceonthisnodereduces
the maximum allowed program resistor value.
Using the previous example with an ambient tem-
perature of 60°C, the charge current will be reduced to
approximately:
105°C – 60°C
(5V – 3.3V)•40°C/W 68°C/A
I= 662mA
45°C
IBAT
=
=
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15
LTC4061
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APPLICATIO S I FOR ATIO
It is important to remember that LTC4061 applications do
notneedtobedesignedforworst-casethermalconditions,
since the IC will automatically reduce power dissipation if
the junction temperature reaches approximately 105°C.
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
NOM
R
needed is calculated as follows:
RCOLD
3.266
2.816
RNOM
=
=
•RNTC at 25°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
•10kΩ = 8.62kΩ
3.266
The nearest 1% value for R
is 8.66kΩ. This is the
NOM
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 R . The values
of the resistors are calculated as follows:
of R
to R
is about 6 also works (Vishay Dale R-T
NTC
COLD
HOT
Curve 1 shows a ratio of R
= 6.13).
to R
of 3.266/0.5325
HOT
COLD
RCOLD – RHOT
3.266 – 0.5325
0.5325
3.266 − 0.5325
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
alsopossible.Thiscurve,combinedwithLTC4061internal
thresholds,givestemperaturetrippointsofapproximately
0°C(falling)and40°C(rising),adeltaof40°C.Thisdeltain
temperature can be moved in either direction by changing
RNOM
=
⎛
⎝
⎞
⎟
⎠
R =
1
•(RCOLD – RHOT )– RHOT
⎜
where R
COLD
is the value of the bias resistor, R
and
NOM
HOT
R
are the values of R
at the desired temperature
NTC
trip points. Continuing the example from before with a
desired hot trip point of 50°C:
the value of R
with respect to R . Increasing R
NOM
NTC NOM
moves both trip points to lower temperatures. Likewise
RCOLD – RHOT 10k •(2.816 – 0.4086)
3.266 – 0.5325
= 8.8kΩ, 8.87k is the nearest1%value.
RNOM
=
=
a decrease in R with respect to R moves the trip
NOM
NTC
3.266 – 0.5325
pointstohighertemperatures.TocalculateR
forashift
NOM
to lower temperatures, use the following equation:
0.5325
3.266 – 0.5325
•(2.816 – 0.4086)– 0.4086
⎛
⎜
⎝
⎞
⎟
⎠
RCOLD
3.266
R = 10k •
1
RNOM
=
•RNTC at 25°C
where R
is the resistance ratio of R
at the desired
COLD
NTC
= 604Ω, 604 is the nearest 1%value.
coldtemperaturetrippoint.Ifyouwanttoshiftthetrippoints
to higher temperatures, use the following equations:
The final solution is R
= 8.87kΩ, R1 = 604Ω and
NOM
R
= 10kΩ at 25°C.
NTC
RHOT
0.5325
RNOM
=
•RNTC at 25°C
NTC Trip Point Error
When a 1% resistor is used for R , the major error
HOT
where R
is the resistance ratio of R
at the desired
NTC
HOT
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-
hot temperature trip point.
Here is an example using 10kΩ R-T Curve 2 thermistor
from Vishay Dale. The difference between the trip points
ficient of the thermistor at 40°C, the tolerance error can
4061fa
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LTC4061
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APPLICATIO S I FOR ATIO
be calculated in degrees centigrade. Consider the Vishay
NTHS0603N01N1003J thermistor, which has a tempera-
ture 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.
U
V
CC
Bypass Capacitor
Many types of capacitors can be used for input bypassing;
however,cautionmustbeexercisedwhenusingmulti-layer
ceramic capacitors. Because of the self-resonant and high
Qcharacteristicsofsometypesofceramiccapacitors,high
voltage transients can be generated under some start-up
conditions such as connecting the charger input to a live
powersource.Addinga1.5Ω resistorinserieswithanX5R
ceramiccapacitorwillminimizestart-upvoltagetransients.
For more information, see Application Note 88.
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
thermistorat0°C, TC(in%/°C), thevalueofthethermistor
Charge Current Soft-Start and Soft-Stop
at 0°C, R
HOT
, and the value of the thermistor at 40°C,
COLD
. The formula is:
R
The LTC4061 includes a soft-start circuit to minimize the
inrushcurrentatthestartofachargecycle. Whenacharge
cycleisinitiated,thechargecurrentrampsfromzerotothe
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.
⎛1+ TOL RCOLD
⎝ 6.14 RHOT
⎞
⎠
•
– 1 •100
⎜
⎟
Temperature Error (°C) =
TC
Forexample,theVishayNTHS0603N01N1003Jthermistor
with a tolerance of 5%, TC of -5%/°C and R
of 6.13, has a cold trip point error of:
/ R
COLD HOT
1+ 0.05
6.14
⎛
⎜
⎝
⎞
⎠
Reverse Polarity Input Voltage Protection
•6.13 – 1 •100
⎟
Temperature Error (°C) =
In some applications, protection from reverse polarity
–5
voltage on V is desired. If the supply voltage is high
CC
= –0.95°C,1.05°C
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).
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
DRAIN-BULK
DIODE OF FET
LTC4061
2
V
IN
V
the PC board ground. Correctly soldered to a 2500mm
CC
4061 F07
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.
Figure 70 Low Loss Input Reverse Polarity Protection
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
4061fa
17
LTC4061
W U U
U
APPLICATIO S I FOR ATIO
5V WALL
ADAPTER
= 800mA
MOSFET, MP1, isusedtopreventbackconductingintothe
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.
I
I
CHG
D1
USB POWER
SYSTEM
LOAD
V BAT
CC
LTC4061
= 500mA
CHG
MP1
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.
I
DET
+
Li-Ion
BATTERY
C/5
PROG
3.3k
MN1
1k
2k 1.25k
4061 F08
Figure 80 Combining Wall Adapter and USB Power
4061fa
18
LTC4061
U
PACKAGE DESCRIPTIO
DD Package
1±-Lead Plastic DFN (.mm × .mm)
(Reference LTC DWG # 05-08-1699)
R = 0.115
0.38 0.10
TYP
6
10
0.675 0.05
3.50 0.05
2.15 0.05 (2 SIDES)
1.65 0.05
3.00 0.10
(4 SIDES)
1.65 0.10
(2 SIDES)
PIN 1
TOP MARK
(SEE NOTE 6)
PACKAGE
OUTLINE
(DD10) DFN 1103
5
1
0.25 0.05
0.50 BSC
0.75 0.05
0.200 REF
0.25 0.05
0.50
BSC
2.38 0.10
(2 SIDES)
2.38 0.05
(2 SIDES)
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
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
4061fa
InformationfurnishedbyLinearTechnologyCorporationisbelievedtobeaccurateandreliable.However,
no responsibility is assumed for its use. Linear Technology Corporation makes no representation that
the interconnection of its circuits as described herein will not infringe on existing patent rights.
19
LTC4061
U
TYPICAL APPLICATIO S
Full-Featured Li-Ion Charger
(Using Time Termination)
USB/Wall Adapter Power Li-Ion Charger
(Using Charge Current Termination)
V
5V
IN
5V
WALL ADAPTER
1µF
1k
1k
10
1
USB
POWER
10
V
BAT
CC
+
V
800mA
Li-Ion
CELL
CC
1
6
5
LTC4061
1µF
BAT
C/5
CHRG
6
9
8
µC
C/5
PROG
V
3
9
IN
TIMER
PROG
4
2
3
ACPR
TIMER
I
100k
DET
+
SINGLE CELL
Li-Ion BATTERY
LTC4061
1.25k
GND
8
1k
2k
2.5k
NTC
I
DET
11
GND
11
100k
NTC
0.1µF
619Ω
4061 TA03
4061 TA02
RELATED PARTS
PART NUMBER
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LTC1734
DESCRIPTION
COMMENTS
Lithium-Ion Linear Battery Charger in ThinSOTTM
Lithium-Ion Linear Battery Charger in ThinSOT
Switch Mode Lithium-Ion Battery Charger
Lithium-Ion Linear Battery Charger Controller
Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed
Low Current Version of LTC1734, 50mA ≤ ICHRG ≤ 180mA
LTC1734L
LTC4002
Standalone, 4.7V ≤ VIN ≤ 24V, 500kHz Frequency, 3 Hour Charge Termination
LTC4050
Features Preset Voltages, C/10 Charger Detection and Programmable Timer,
Input Power Good Indication, Thermistor Interface
LTC4052
LTC4053
LTC4054
Monolithic Lithium-Ion Battery Pulse Charger
No Blocking Diode or External Power FET Required, ≤1.5A Charge Current
Standalone Charger with Programmable Timer, Up to 1.25A Charge Current
USB Compatible Monolithic Li-Ion Battery Charger
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
LTC4058
LTC4059
Lithium-Ion Linear Battery Charger
Up to 800mA Charge Current, Thermal Regulation, ThinSOT Package
C/10 Charge Termination, Battery Kelvin Sensing, 7% Charge Accuracy
Standalone 950mA Lithium-Ion Charger in DFN
900mA Linear Lithium-Ion Battery Charger
2mm x 2mm DFN Package, Thermal Regulation, Charge Current Monitor
Output
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 (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
LTC3440
LTC4413
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
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
Dual Ideal Diode in DFN
2-Channel Ideal Diode ORing, Low Forward ON Resistance, Low Regulated
Forward Voltage, 2.5V ≤ V ≤ 5.5V
IN
ThinSOT and PowerPath are trademarks of Linear Technology Corporation.
4061fa
LT/TP 0305 1K REV A • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
20
●
●
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2004
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