FEATURES
■
LTC4080X
500mA Standalone Li-Ion
Charger with Integrated 300mA
Synchronous Buck in 3mm
×
3mm DFN
DESCRIPTIO
The LTC4080X is a complete constant-current/constant-
voltage linear battery charger for a single-cell 4.2V
lithium-ion/polymer battery with an integrated 300mA
synchronous buck converter. A 3mm
×
3mm DFN package
and low external component count make the LTC4080X
especially suitable for portable applications. Furthermore,
the LTC4080X is specifically designed to work within USB
power specifications.
The
⎯
C
⎯
H
⎯
R
⎯
G pin indicates when charge current has
dropped to ten percent of its programmed value (C/10).
An internal 4.5 hour timer terminates the charge cycle.
The full-featured LTC4080X battery charger also includes
automatic recharge and soft-start to limit inrush current.
If trickle charging is desired, please see the LTC4080
datasheet.
The LTC4080X integrates a synchronous buck converter
that is powered from the BAT pin. It has an adjustable
output voltage and can deliver up to 300mA of load cur-
rent. The buck converter also features low-current high-
efficiency Burst Mode operation that can be selected by
the MODE pin.
The LTC4080X is available in 10-lead, low profile (0.75 mm)
3mm
×
3mm DFN and 10-lead MSE packages.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation. All other
trademarks are the property of their respective owners. Protected by U.S. Patents,
including 6522118.
Complete Linear Battery Charger with Integrated
Buck Converter in 3mm x 3mm DFN Package
Battery Charger:
■
Constant-Current/Constant-Voltage Operation
with Thermal Feedback to Maximize Charge Rate
Without Risk of Overheating
■
Internal 4.5 Hour Safety Timer for Termination
■
Charge Current Programmable Up to 500mA with
5% Accuracy
■
C/10 Charge Current Detection Output
■
5µA Supply Current in Shutdown Mode
Switching Regulator:
■
High Efficiency Synchronous Buck Converter
■
300mA Output Current (Constant-Frequency Mode)
■
2.7V to 4.5V Input Range (Powered from BAT Pin)
■
0.8V to V
BAT
Output Range
■
MODE Pin Selects Fixed (2.25MHz) Constant-Frequency
PWM Mode or Low I
CC
(23µA) Burst Mode
®
Operation
■
2µA BAT Current in Shutdown Mode
APPLICATIO S
■
■
■
■
Wireless Headsets
Bluetooth Applications
Portable MP3 Players
Multifunction Wristwatches
TYPICAL APPLICATIO
V
CC
(3.75V
to 5.5V)
V
CC
LTC4080X
EN_CHRG
4.7µF
EN_BUCK
SW
FB
BAT
Li-Ion Battery Charger with 1.8V Buck Regulator
500mA
100
EFFICIENCY
(Burst)
EFFICIENCY
(PWM)
80
EFFICIENCY (%)
1OµH
4.7µF
+
4.2V
Li-Ion/
POLYMER
BATTERY
60
10pF
1M
V
OUT
(1.8V/300mA)
40
MODE GND PROG
806Ω
806k
4080X TA01a
20
C
OUT
4.7µF
U
U
U
Buck Efficiency vs Load Current
(V
OUT
= 1.8V)
1000
100
POWER LOSS (mW)
POWER
LOSS 10
(PWM)
1
POWER LOSS
(Burst)
0
0.01
V
BAT
= 3.8V 0.1
V
OUT
= 1.8V
L = 10µH
C = 4.7µF
0.01
0.1
1
10
100
1000
LOAD CURRENT (mA)
4080X TA01b
4080Xf
1
LTC4080X
ABSOLUTE
(Note 1)
AXI U RATI GS
BAT Short-Circuit Duration............................Continuous
BAT Pin Current ...................................................800mA
PROG Pin Current ....................................................2mA
Junction Temperature .......................................... .125°C
Operating Temperature Range (Note 2) .. – 40°C to 85°C
Storage Temperature Range.................. – 65°C to 125°C
V
CC
, t < 1ms and Duty Cycle < 1% .............. – 0.3V to 7V
V
CC
Steady State ......................................... – 0.3V to 6V
BAT,
⎯
C
⎯
H
⎯
R
⎯
G .................................................. – 0.3V to 6V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G, PROG,
⎯
A
⎯
C
⎯
P
⎯
R .................– 0.3V to V
CC
+ 0.3V
MODE, EN_BUCK .......................... – 0.3V to V
BAT
+ 0.3V
FB ............................................................... – 0.3V to 2V
PIN CONFIGURATION
TOP VIEW
BAT
V
CC
EN_CHRG
PROG
ACPR
1
2
3
4
5
11
10 SW
9 EN_BUCK
8 MODE
7 FB
6 CHRG
TOP VIEW
BAT
V
CC
EN_CHRG
PROG
ACPR
1
2
3
4
5
10
9
8
7
6
SW
EN_BUCK
MODE
FB
CHRG
DD PACKAGE
10-LEAD (3mm
×
3mm) PLASTIC DFN
T
JMAX
= 110°C,
θ
JA
= 43°C/W (NOTE 3)
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC4080XEDD#PBF
LTC4080XEMSE#PBF
TAPE AND REEL
LTC4080XEDD#TRPBF
LTC4080XEMSE#TRPBF
PART MARKING
LCVV
LTCVW
PACKAGE DESCRIPTION
10-Lead (3mm
×
3mm) DFN
10-Lead Plastic MSE
TEMPERATURE RANGE
0°C to 70°C
0°C to 70°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/
2
U
W W
W
11
MSE PACKAGE
10-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 40°C/W
EXPOSED PAD (PIN 11) IS GND, MUST BE SOLDERED TO PCB
4080Xf
LTC4080X
ELECTRICAL CHARACTERISTICS
SYMBOL
V
CC
V
BAT
I
CC
I
CC_SD
PARAMETER
Battery Charger Supply Voltage
Input Voltage for the Switching
Regulator
The
●
denotes specifications which apply over the full operating tempera-
ture range, otherwise specifications are at T
A
= 25°C, V
CC
= 5V, V
BAT
= 3.8V, V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G
= 0V, V
EN_BUCK
= V
BAT
, V
MODE
= 0V. (Note 2)
CONDITIONS
(Note 4)
(Note 5)
●
●
●
●
MIN
3.75
2.7
TYP
5
3.8
110
5
2
0.6
2
MAX
5.5
4.5
300
10
UNITS
V
V
µA
µA
µA
µA
µA
Quiescent Supply Current (Charger On, V
BAT
= 4.5V (Forces I
BAT
and I
PROG
= 0),
Switching Regulator Off)
V
EN_BUCK
= 0
Supply Current in Shutdown (Both
Battery Charger and Switching
Regulator Off)
Battery Current in Shutdown (Both
Battery Charger and Switching
Regulator Off)
V
BAT
Regulated Output Voltage
Current Mode Charge Current
V
CC
Undervoltage Lockout Voltage
PROG Pin Servo Voltage
V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G
= 5V, V
EN_BUCK
= 0, V
CC
> V
BAT
V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G
= 4V, V
EN_BUCK
= 0, V
CC
(3.5V) <
V
BAT
(4V)
V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G
= 5V, V
EN_BUCK
= 0, V
CC
> V
BAT
V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G
= 4V, V
EN_BUCK
= 0, V
CC
(3.5V) <
V
BAT
(4V)
I
BAT
= 2mA
I
BAT
= 2mA, 4.3V < V
CC
< 5.5V
R
PROG
= 4k; Current Mode; V
EN_BUCK
= 0
R
PROG
= 0.8k; Current Mode; V
EN_BUCK
= 0
V
CC
Rising
V
CC
Falling
0.8k ≤ R
PROG
≤ 4k
I
BAT_SD
●
5
Battery Charger
V
FLOAT
I
BAT
V
UVLO_CHRG
V
PROG
V
ASD
t
SS_CHRG
V
BADBAT
ΔV
RECHRG
ΔV
UVCL1,
ΔV
UVCL2
t
TIMER
●
●
●
●
●
●
4.179
4.158
90
475
3.5
2.8
0.98
60
15
4.2
4.2
100
500
3.6
3.0
1.0
82
32
180
2.9
4.221
4.242
110
525
3.7
3.2
1.02
100
45
V
V
mA
mA
V
V
V
mV
mV
µs
V
Automatic Shutdown Threshold Voltage (V
CC
– V
BAT
), V
CC
Low to High
(V
CC
– V
BAT
), V
CC
High to Low
Battery Charger Soft-Start Time
Bad Battery Threshold Voltage
Recharge Battery Threshold Voltage
(V
CC
– V
BAT
) Undervoltage Current
Limit Threshold Voltage
Charge Termination Timer
Recharge Time
Low-Battery Charge Time
V
BAT
= 2.5V
R
PROG
= 2k (Note 6)
V
FLOAT
– V
BAT
, 0°C < T
A
< 85°C
I
BAT
= 0.9 I
CHG
I
BAT
= 0.1 I
CHG
●
●
●
●
70
180
90
3
1.5
0.75
0.085
100
300
130
4.5
2.25
1.125
0.1
115
750
2
75
130
mV
mV
mV
6
3
1.5
0.115
hrs
hrs
hrs
mA/mA
°C
mΩ
Hz
%
I
C/10
T
LIM
R
ON_CHRG
f
BADBAT
D
BADBAT
Buck Converter
V
FB
I
FB
f
OSC
I
BAT_NL_CF
End of Charge Indication Current Level
Junction Temperature in Constant-
Temperature Mode
I
BAT
= 350mA, V
CC
= 4V
Power FET On-Resistance (Between
V
CC
and BAT)
⎯ ⎯ ⎯ ⎯
Defective Battery Detection CHRG Pulse V
BAT
= 2V
Frequency
⎯ ⎯ ⎯ ⎯
Defective Battery Detection CHRG Pulse V
BAT
= 2V
Frequency Duty Ratio
FB Servo Voltage
FB Pin Input Current
Switching Frequency
No-Load Battery Current (Continuous
Frequency Mode)
No-Load for Regulator, V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G
= 5V,
L = 10µH, C = 4.7µF
V
FB
= 0.85V
●
●
0.78
–50
1.8
0.80
2.25
1.9
0.82
50
2.75
V
nA
MHz
mA
4080Xf
3
LTC4080X
ELECTRICAL CHARACTERISTICS
SYMBOL
I
BAT_NL_BM
I
BAT_SLP
V
UVLO_BUCK
R
ON_P
R
ON_N
I
LIM_P
I
LIM_N
I
ZERO_CF
I
PEAK
I
ZERO_BM
t
SS_BUCK
Logic
V
IH
V
IL
V
OL
I
IH
I
IL
R
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G
I
⎯
C
⎯
H
⎯
R
⎯
G
I
⎯
A
⎯
C
⎯
P
⎯
R
Input High Voltage
Input Low Voltage
Output Low Voltage (
⎯
C
⎯
H
⎯
R
⎯
G,
⎯
A
⎯
C
⎯
P
⎯
R)
Input Current High
Input Current Low
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G Pin Input Resistance
⎯
C
⎯
H
⎯
R
⎯
G Pin Leakage Current
⎯
A
⎯
C
⎯
P
⎯
R Pin Leakage Current
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G, EN_BUCK, MODE Pin Low to High
⎯ ⎯
EN
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G, EN_BUCK, MODE Pin High to Low
I
SINK
= 5mA
EN_BUCK, MODE Pins at 5.5V, V
BAT
= 5V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G, EN_BUCK, MODE Pins at GND
V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G
= 5V
V
BAT
= 4.5V, V
⎯
C
⎯
H
⎯
R
⎯
G
= 5V
V
CC
= 3V, V
⎯
C
⎯
H
⎯
R
⎯
G
= 5V
●
●
●
●
●
●
●
The
●
denotes specifications which apply over the full operating tempera-
ture range, otherwise specifications are at T
A
= 25°C, V
CC
= 5V, V
BAT
= 3.8V, V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G
= 0V, V
EN_BUCK
= V
BAT
, V
MODE
= 0V. (Note 2)
PARAMETER
No-Load Battery Current (Burst Mode
Operation)
Battery Current in SLEEP Mode
Buck Undervoltage Lockout Voltage
PMOS Switch On-Resistance
NMOS Switch On-Resistance
PMOS Switch Current Limit
NMOS Switch Current Limit
NMOS Zero Current in Normal Mode
Peak Current in Burst Mode Operation
Zero Current in Burst Mode Operation
Buck Soft-Start Time
MODE = V
BAT
MODE = V
BAT
From the Rising Edge of EN_BUCK to 90%
of Buck Regulated Output
50
20
375
CONDITIONS
No-Load for Regulator, V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G
= 5V,
MODE = V
BAT
, L = 10µH, C = 4.7µF
V
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G
= 5V, MODE = V
BAT
,
V
OUT
> Regulation Voltage
V
BAT
Rising
V
BAT
Falling
●
●
●
MIN
TYP
23
MAX
UNITS
µA
10
2.6
2.4
15
2.7
2.5
0.95
0.85
520
700
15
100
35
400
20
2.8
2.6
µA
V
V
Ω
Ω
700
mA
mA
mA
150
50
mA
mA
µs
1.2
0.4
60
–1
–1
1
1.45
105
1
1
3.3
1
1
V
V
mV
µA
µA
MΩ
µA
µA
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 LTC4080X is guaranteed to meet performance specifications
from 0°C to 85°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 solder the exposed backside of the package to the PC
board ground plane will result in a thermal resistance much higher than
43°C/W.
Note 4:
Although the LTC4080X charger functions properly at 3.75V, full
charge current requires an input voltage greater than the desired final
battery voltage per
ΔV
UVCL1
specification.
Note 5:
The 2.8V maximum buck undervoltage lockout (V
UVLO_BUCK
) exit
threshold must first be exceeded before the minimum V
BAT
specification
applies.
Note 6:
I
C/10
is expressed as a fraction of measured full charge current
with indicated PROG resistor.
4080Xf
4
LTC4080X
TYPICAL PERFORMANCE CHARACTERISTICS
specified)
Battery Regulation (Float) Voltage
vs Charge Current
4.21
4.20
FLOAT VOLTAGE (V)
4.19
FLOAT VOLTAGE (V)
4.18
4.17
4.16
4.15
4.14
4.13
0
50
200
150
100
CHARGE CURRENT (mA)
250
4080X G01
(T
A
= 25°C, V
CC
= 5V, V
BAT
= 3.8V, unless otherwise
Battery Regulation (Float) Voltage
vs V
CC
Supply Voltage
4.25
4.20
4.15
FLOAT VOLTAGE (V)
4.10
4.05
4.00
3.95
3.90
3.85
Battery Regulation (Float) Voltage
vs Temperature
4.210
4.205
4.200
4.195
4.190
4.185
4.180
4.175
4.170
4.165
4.160
– 50 – 30
– 10
50
30
10
TEMPERATURE (°C)
70
90
R
PROG
= 2k
4
4.5
5
5.5
V
CC
SUPPLY VOLTAGE (V)
6
4080X G03
4080X G02
Charge Current vs Temperature
with Thermal Regulation
(Constant-Current Mode)
250
V
CC
= 6V
V
BAT
= 3V
R
PROG
= 2k
1.0
PROG Pin Voltage
vs Charge Current
0.9
R
PROG
= 2k
0.8
Charger FET On-Resistance
vs Temperature
V
CC
= 4V
0.8 I
BAT
= 350mA
0.7
0.6
R
DS(ON)
(Ω)
200
CHARGE CURRENT (mA)
THERMAL CONTROL
LOOP IN OPERATION
V
PROG
(V)
150
0.6
0.5
0.4
0.3
100
0.4
50
0.2
0.2
0.1
0
–50
–25
0
25
50
75
100
125
0
0
25
TEMPERATURE (°C)
4080X G04
50 75 100 125 150 175 200
CHARGE CURRENT (mA)
4080X G05
0
– 50 – 30
–10
30
50
10
TEMPERATURE (°C)
70
90
4080X G06
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G, EN_BUCK and
MODE Pin Threshold Voltage
vs Temperature
0.95
0.90
THRESHOLD VOLTAGE (V)
0.85
0.80
0.75
0.70
0.65
0.60
0.55
0.50
–50
–30
–10 10
30
50
TEMPERATURE (°C)
70
90
4080X G07
⎯
E
⎯
N
⎯
_
⎯
C
⎯
H
⎯
R
⎯
G Pin Pulldown
Resistance vs Temperature
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
–50
FALLING
PULLDOWN RESISTANCE (MΩ)
RISING
–30
–10 10
30
50
TEMPERATURE (°C)
70
90
4080X G08
4080Xf
5
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