LTC1733
Monolithic Linear
Lithium-Ion Battery Charger with
Thermal Regulation
FEATURES
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DESCRIPTIO
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Complete Linear Charger for 1-Cell Lithium-Ion
Batteries
Thermal Regulation Maximizes Charging Rate
without Risk of Overheating*
No External MOSFET, Sense Resistor or Blocking
Diode Required
Up to 1.5A Charge Current
Preset Charge Voltage with 1% Accuracy
Programmable Charge Current with 7% Accuracy
Programmable Charge Termination Timer
Tiny Thermally Enhanced 10-Pin MSOP Package
Charge Current Monitor Useful for Gas Gauging*
C/10 Charge Current Detection Output
Automatic Recharge
Thermistor Input for Temperature Qualified Charging
AC Present Logic Output
4.1V/4.2V Pin Selectable Output Voltage
The LTC
®
1733 is a standalone constant-current/
constant-voltage linear charger for lithium-ion batteries
with an on-chip power MOSFET. Internal thermal feedback
regulates the charge current to limit die temperature
during high power operation or high ambient temperature
conditions. This feature allows the user to program a high
charge current without risk of damaging the LTC1733 or
the handheld product.
No external current sense resistor is needed and no
blocking diode is required due to the internal MOSFET
architecture. The charge current and charge time can be
set externally with a single resistor and capacitor, respec-
tively. When the input supply (wall adapter) is removed,
the LTC1733 automatically enters a low current sleep
mode, dropping the battery drain current to less than 5µA.
The LTC1733 also includes NTC temperature sensing,
C/10 detection circuitry, AC present logic, 4.1V/4.2V pin
selectability and low battery charge conditioning (trickle
charging).
The LTC1733 is available in a 10-pin thermally enhanced
MSOP package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
*Patent Pending
APPLICATIO S
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Cellular Telephones
Handheld Computers
Digital Still Cameras
Charging Docks and Cradles
TYPICAL APPLICATIO
V
IN
= 5V
Charge Current vs Battery Voltage
Standalone Li-Ion Battery Charger
1200
T
A
= 0°C
1000
CHARGE CURRENT (mA)
8
SEL
4.7µF
4
2
V
CC
BAT
9
I
BAT
= 1A
4.2V
1-CELL
Li-Ion
BATTERY*
800
600
400
200 TRICKLE
CHARGE
0
2
2.5
LTC1733
7
TIMER
PROG
GND
NTC
6
5
1.5k
1%
1733TA01
0.1µF
*AN OUTPUT CAPACITOR MAY BE REQUIRED
DEPENDING ON BATTERY LEAD LENGTH
U
CONSTANT
CURRENT
T
A
= 40°C
T
A
= 25°C
CONSTANT
POWER
CONSTANT
VOLTAGE
V
IN
= 5V
θ
JA
= 40°C/W
3
4
3.5
BATTERY VOLTAGE (V)
4.5
1733 TA01b
U
U
sn1733 1733fs
1
LTC1733
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
CHRG
V
CC
FAULT
TIMER
GND
1
2
3
4
5
10
9
8
7
6
ACPR
BAT
SEL
PROG
NTC
Input Supply Voltage (V
CC
) ........................................ 7V
BAT ............................................................................ 7V
NTC, SEL, TIMER, PROG ................ –0.3V to V
CC
+ 0.3V
CHRG, FAULT, ACPR ................................... –0.3V to 7V
BAT Short-Circuit Duration ........................... Continuous
BAT Current (Note 2) .............................................. 1.6A
PROG Current (Note 2) ........................................ 1.6mA
Junction Temperature ........................................... 125°C
Operating Temperature Range (Note 3) ...–40°C to 85°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
ORDER PART
NUMBER
LTC1733EMSE
MSE PART MARKING
LTLX
MSE EXPOSED PAD PACKAGE
10-LEAD PLASTIC MSOP
T
JMAX
= 125°C,
θ
JA
= 40°C/W (Note 4)
EXPOSED PAD IS GROUND.
(MUST BE SOLDERED TO PCB
FOR MAXIMUM HEAT TRANSFER).
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 5V
SYMBOL
V
CC
I
CC
V
BAT
I
BAT
PARAMETER
V
CC
Supply Voltage
V
CC
Supply Current
V
BAT
Regulated Output Voltage
Battery Pin Current
Charger On; Current Mode; R
PROG
= 30k (Note 5)
Shutdown Mode; V
PROG
= 3V
SEL = 0V
SEL = V
CC
R
PROG
= 3k; Current Mode
R
PROG
= 1k; Current Mode
Shutdown Mode; V
PROG
= 3V
Sleep Mode V
CC
< V
BAT
or V
CC
< (V
UV
–
∆V
UV
)
V
BAT
< 2V; R
PROG
= 3k
V
BAT
Rising
V
CC
Rising
PROG Pin Voltage Rising
q
ELECTRICAL CHARACTERISTICS
CONDITIONS
q
q
q
q
q
q
MIN
4.5
TYP
1
0.9
MAX
6.5
3
2
4.141
4.242
535
1.605
±5
±5
65
UNITS
V
mA
mA
V
V
mA
A
µA
µA
mA
V
mV
4.059
4.158
465
1.395
4.1
4.2
500
1.5
±1
±1
50
2.48
100
4.2
150
2.15
100
30
60
I
TRIKL
V
TRIKL
∆V
TRIKL
V
UV
∆V
UV
V
MSD
V
MSD-HYS
V
ASD
Trickle Charge Current
Trickle Charge Trip Threshold
Trickle Charge Trip Hysteresis
V
CC
Undervoltage Lockout Voltage
V
CC
Undervoltage Lockout Hysteresis
Manual Shutdown Threshold Voltage
Manual Shutdown Hysteresis Voltage
q
35
4.5
Automatic Shutdown Threshold Voltage (V
CC
- V
BAT
) Voltage Falling
(V
CC
- V
BAT
) Voltage Rising
sn1733 1733fs
2
U
V
mV
V
mV
mV
mV
W
U
U
W W
W
LTC1733
ELECTRICAL CHARACTERISTICS
SYMBOL
V
PROG
I
CHRG
V
CHRG
V
ACPR
V
FAULT
I
C/10
t
TIMER
V
RECHRG
V
NTC-HOT
V
HOT-HYS
V
NTC-COLD
V
COLD-HYS
V
NTC-DIS
V
DIS-HYS
V
SEL-IL
V
SEL-IH
T
LIM
R
ON
PARAMETER
PROG Pin Voltage
CHRG Pin Weak Pulldown Current
CHRG Pin Output Low Voltage
ACPR Pin Output Low Voltage
FAULT Pin Output Low Voltage
End of Charge Indication Current Level
TIMER Accuracy
Recharge Battery Voltage Threshold
NTC Pin Hot Threshold Voltage
NTC Pin Hot Hysteresis Voltage
NTC Pin Cold Threshold Voltage
NTC Pin Cold Hystersis Voltage
NTC Pin Disable Threshold Voltage
NTC Pin Disable Hystersis Voltage
SEL Pin Threshold Input Low
SEL Pin Threshold Input High
Junction Temperature in
Constant-Temperature Mode
Power MOSFET “ON” Resistance
105
375
0.3
1
V
NTC
Rising
V
NTC
Rising
T
A
= 25°C. V
CC
= 5V unless otherwise noted.
MIN
TYP
1.5
25
0.35
0.35
0.35
35
50
±10
3.9
4.0
2.5
70
4.375
70
100
10
65
MAX
UNITS
V
µA
V
V
V
mA
%
V
V
V
mV
V
mV
mV
mV
V
V
°C
mΩ
CONDITIONS
R
PROG
= 3k, I
PROG
= 500µA; Current Mode
V
CHRG
= 1V
I
CHRG
= 5mA
I
ACPR
= 5mA
I
FAULT
= 5mA
R
PROG
= 3k
C
TIMER
= 0.1µF
Battery Voltage Falling, SEL = 0V
Battery Voltage Falling, SEL = 5V
V
NTC
Falling
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
The Absolute Maximum BAT Current Rating of 1.6A is guaranteed
by design and current density calculations. The Absolute Maximum PROG
Current Rating is guaranteed to be 1/1000 of BAT current rating by design.
Note 3:
The LTC1733E 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:
Failure to solder the exposed backside of the package to the PC
board will result in a thermal resistance much higher than 40°C/W.
Note 5:
Supply current includes PROG pin current but does not include
any current delivered to the battery through the BAT pin.
sn1733 1733fs
3
LTC1733
TYPICAL PERFOR A CE CHARACTERISTICS
Battery Regulation Voltage vs
Battery Charge Current
4.24
4.22 V
SEL
= 5V
4.20
4.18
V
BAT
(V)
V
CC
= 5V
T
A
= 25°C
R
PROG
= 1.5k
4.16
4.14
4.12 V
SEL
= 0V
4.10
4.08
4.06
0 100 200 300 400 500 600 700 800 900 1000
I
BAT
(mA)
1733 G01
V
BAT
(V)
V
BAT
(V)
PROG Pin Voltage vs Charge
Current
1.6
V
CC
= 5V
T
A
= 25°C
1.4
R
PROG
= 1.5k
V
SEL
= 5V
1.2
V
PROG
(V)
1100
I
BAT
(mA)
0.8
0.6
0.4
0.2
0
0 100 200 300 400 500 600 700 800 900 1000
CHARGE CURRENT (mA)
1733 G04
600
500
400
300
200
100
0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
V
BAT
(V)
1733 G05
I
BAT
(mA)
1.0
Charge Current vs V
CC
1100
R
PROG
= 1.5k
1000
900
1000
900
800
700
V
BAT
= 3.5V
T
A
= 25°C
V
SEL
= V
CC
I
BAT
(mA)
I
BAT
(mA)
800
700
600
500
400
4.0
R
PROG
= 3k
500
400
300
V = 5V
200 V
CC
= 3.5V
BAT
100 R
PROG
= 1.5k
V
SEL
= 5V
0
–25
25
0
–50
50
TEMPERATURE (°C)
I
BAT
(mA)
4.5
5.0
5.5
V
CC
(V)
6.0
4
U W
6.5
Battery Regulation Voltage vs
Temperature
4.24
V
CC
= 5V
4.22 I
BAT
= 10mA
R
PROG
= 1.5k
4.20
4.18
4.16
4.14
4.12
4.10
4.08
4.06
–50
–25
25
0
50
75
TEMPERATURE(°C)
100
125
V
SEL
= 0V
Battery Regulation Voltage vs V
CC
4.24
T
A
= 25°C
4.22 I
BAT
= 10mA
R
PROG
= 1.5k
4.20
4.18
4.16
4.14
4.12
4.10
4.08
4.06
4.0
4.5
5.0
5.5
V
CC
(V)
1733 G02
V
SEL
= 5V
V
SEL
= V
CC
V
SEL
= 0V
6.0
6.5
7.0
1733 G03
Charge Current vs Battery Voltage
V
CC
= 5V
1000 T
A
= 25°C
900 R
PROG
= 1.5k
V
SEL
= 5V
800
700
1100
1000
900
800
700
600
500
400
300
200
100
0
Charge Current vs Input Voltage
V
BAT
= 4.1V
T
A
= 25°C
R
PROG
= 1.5k
V
SEL
= 5V
4.0
4.5
5.0
5.5
V
CC
(V)
6.0
6.5
7.0
1733 G06
Charge Current vs Temperature
with Thermal Regulation
Charge Current vs Temperature
535
530
525
520
515
510
505
500
495
490
485
480
475
470
465
–50
V
CC
= 5V
V
BAT
= 4V
R
PROG
= 3k
V
SEL
= 5V
600
THERMAL CONTROL
LOOP IN OPERATION
7.0
75
100
–25
50
25
0
TEMPERATURE (°C)
75
100
1733 G07
1733 G08
1733 G09
sn1733 1733fs
LTC1733
TYPICAL PERFOR A CE CHARACTERISTICS
PROG Pin Voltage vs V
CC
Constant Current Mode
1.515
1.510
1.505
T
A
= 25°C
V
BAT
= 3.5V
R
PROG
= 3k
V
SEL
= 5V
V
PROG
(V)
V
PROG
(V)
1.500
1.495
1.490
1.485
4.0
I
BAT
(mA)
4.5
5.0
5.5
V
CC
(V)
6.0
Trickle Charge Current vs V
CC
13
I
BAT
(% OF PROGRAMMED CURRENT)
12
11
T
A
= 25°C
V
BAT
= 2V
R
PROG
= 1.5k
V
SEL
= 5V
t
TIMER
(%)
10
9
8
7
4.0
100
99
98
97
96
t
TIMER
(%)
4.5
5.0
5.5
V
CC
(V)
6.0
U W
6.5
PROG Pin Voltage vs Temperature
Constant Current Mode
1.515
1.510
1.505
1.500
1.495
1.490
1.485
–50
V
CC
= 5V
V
BAT
= 4V
R
PROG
= 3k
V
SEL
= 5V
130
120
110
100
90
80
Trickle Charge Current vs
Temperature
V
CC
= 5V
V
BAT
= 2V
R
PROG
= 1.5k
V
SEL
= 5V
7.0
–25
50
25
0
TEMPERATURE (°C)
75
100
70
–50
–25
50
25
0
TEMPERATURE (°C)
75
100
1733 G10
1733 G11
1733 G12
Timer Accuracy vs Temperature
105
104
103
102
101
V
CC
= 5V
I
BAT
= 0mA
V
SEL
= 5V
C
TIMER
= 0.1µF
105
104
103
102
101
100
99
98
97
96
–25
25
0
50
75
TEMPERATURE(°C)
100
125
Timer Accuracy vs V
CC
T
A
= 25°C
I
BAT
= 0mA
V
SEL
= 5V
C
TIMER
= 0.1µF
6.5
7.0
95
–50
95
4.0
4.5
5.0
5.5
V
CC
(V)
6.0
6.5
7.0
1733 G15
1733 G13
1733 G14
sn1733 1733fs
5
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