LTC1733
1
sn1733 1733fs
DESCRIPTIO
U
FEATURES
APPLICATIO S
U
TYPICAL APPLICATIO
U
s
Cellular Telephones
s
Handheld Computers
s
Digital Still Cameras
s
Charging Docks and Cradles
s
Complete Linear Charger for 1-Cell Lithium-Ion
Batteries
s
Thermal Regulation Maximizes Charging Rate
without Risk of Overheating*
s
No External MOSFET, Sense Resistor or Blocking
Diode Required
s
Up to 1.5A Charge Current
s
Preset Charge Voltage with 1% Accuracy
s
Programmable Charge Current with 7% Accuracy
s
Programmable Charge Termination Timer
s
Tiny Thermally Enhanced 10-Pin MSOP Package
s
Charge Current Monitor Useful for Gas Gauging*
s
C/10 Charge Current Detection Output
s
Automatic Recharge
s
Thermistor Input for Temperature Qualified Charging
s
AC Present Logic Output
s
4.1V/4.2V Pin Selectable Output Voltage
Monolithic Linear
Lithium-Ion Battery Charger with
Thermal Regulation
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 5
A.
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.
Charge Current vs Battery Voltage
Standalone Li-Ion Battery Charger
BATTERY VOLTAGE (V)
2
CHARGE CURRENT (mA)
3.5
1733 TA01b
2.5
3
4
4.5
1200
1000
800
600
400
200
0
TRICKLE
CHARGE
CONSTANT
CURRENT
CONSTANT
VOLTAGE
CONSTANT
POWER
T
A
= 40
C
T
A
= 0
C
V
IN
= 5V
JA
= 40
C/W
T
A
= 25
C
*Patent Pending
BAT
PROG
TIMER
GND
V
CC
V
IN
= 5V
1.5k
1%
4.7
F
0.1
F
I
BAT
= 1A
1733TA01
LTC1733
4.2V
1-CELL
Li-Ion
BATTERY*
*AN OUTPUT CAPACITOR MAY BE REQUIRED
DEPENDING ON BATTERY LEAD LENGTH
2
8
9
7
5
NTC
6
4
SEL
LTC1733
2
sn1733 1733fs
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
ABSOLUTE AXI U
RATI GS
W
W
W
U
PACKAGE/ORDER I FOR ATIO
U
U
W
(Note 1)
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
CC
V
CC
Supply Voltage
q
4.5
6.5
V
I
CC
V
CC
Supply Current
Charger On; Current Mode; R
PROG
= 30k (Note 5)
q
1
3
mA
Shutdown Mode; V
PROG
= 3V
q
0.9
2
mA
V
BAT
V
BAT
Regulated Output Voltage
SEL = 0V
q
4.059
4.1
4.141
V
SEL = V
CC
q
4.158
4.2
4.242
V
I
BAT
Battery Pin Current
R
PROG
= 3k; Current Mode
q
465
500
535
mA
R
PROG
= 1k; Current Mode
1.395
1.5
1.605
A
Shutdown Mode; V
PROG
= 3V
1
5
A
Sleep Mode V
CC
< V
BAT
or V
CC
< (V
UV
V
UV
)
1
5
A
I
TRIKL
Trickle Charge Current
V
BAT
< 2V; R
PROG
= 3k
q
35
50
65
mA
V
TRIKL
Trickle Charge Trip Threshold
V
BAT
Rising
2.48
V
V
TRIKL
Trickle Charge Trip Hysteresis
100
mV
V
UV
V
CC
Undervoltage Lockout Voltage
V
CC
Rising
q
4.2
4.5
V
V
UV
V
CC
Undervoltage Lockout Hysteresis
150
mV
V
MSD
Manual Shutdown Threshold Voltage
PROG Pin Voltage Rising
2.15
V
V
MSD-HYS
Manual Shutdown Hysteresis Voltage
100
mV
V
ASD
Automatic Shutdown Threshold Voltage (V
CC
- V
BAT
) Voltage Falling
30
mV
(V
CC
- V
BAT
) Voltage Rising
60
mV
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ORDER PART
NUMBER
LTC1733EMSE
T
JMAX
= 125
C,
JA
= 40
C/W (Note 4)
EXPOSED PAD IS GROUND.
(MUST BE SOLDERED TO PCB
FOR MAXIMUM HEAT TRANSFER).
MSE PART MARKING
LTLX
1
2
3
4
5
CHRG
V
CC
FAULT
TIMER
GND
10
9
8
7
6
ACPR
BAT
SEL
PROG
NTC
TOP VIEW
MSE EXPOSED PAD PACKAGE
10-LEAD PLASTIC MSOP
The
q
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25
C. V
CC
= 5V
LTC1733
3
sn1733 1733fs
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
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
V
PROG
PROG Pin Voltage
R
PROG
= 3k, I
PROG
= 500
A; Current Mode
1.5
V
I
CHRG
CHRG Pin Weak Pulldown Current
V
CHRG
= 1V
25
A
V
CHRG
CHRG Pin Output Low Voltage
I
CHRG
= 5mA
0.35
V
V
ACPR
ACPR Pin Output Low Voltage
I
ACPR
= 5mA
0.35
V
V
FAULT
FAULT Pin Output Low Voltage
I
FAULT
= 5mA
0.35
V
I
C/10
End of Charge Indication Current Level
R
PROG
= 3k
35
50
65
mA
t
TIMER
TIMER Accuracy
C
TIMER
= 0.1
F
10
%
V
RECHRG
Recharge Battery Voltage Threshold
Battery Voltage Falling, SEL = 0V
3.9
V
Battery Voltage Falling, SEL = 5V
4.0
V
V
NTC-HOT
NTC Pin Hot Threshold Voltage
V
NTC
Falling
2.5
V
V
HOT-HYS
NTC Pin Hot Hysteresis Voltage
70
mV
V
NTC-COLD
NTC Pin Cold Threshold Voltage
V
NTC
Rising
4.375
V
V
COLD-HYS
NTC Pin Cold Hystersis Voltage
70
mV
V
NTC-DIS
NTC Pin Disable Threshold Voltage
V
NTC
Rising
100
mV
V
DIS-HYS
NTC Pin Disable Hystersis Voltage
10
mV
V
SEL-IL
SEL Pin Threshold Input Low
0.3
V
V
SEL-IH
SEL Pin Threshold Input High
1
V
T
LIM
Junction Temperature in
105
C
Constant-Temperature Mode
R
ON
Power MOSFET "ON" Resistance
375
m
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.
ELECTRICAL CHARACTERISTICS
T
A
= 25
C. V
CC
= 5V unless otherwise noted.
LTC1733
4
sn1733 1733fs
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
Battery Regulation Voltage vs
Battery Charge Current
Battery Regulation Voltage vs
Temperature
Battery Regulation Voltage vs V
CC
PROG Pin Voltage vs Charge
Current
Charge Current vs Temperature
I
BAT
(mA)
4.24
4.22
4.20
4.18
4.16
4.14
4.12
4.10
4.08
4.06
V
BAT
(V)
1733 G01
0 100 200 300 400 500 600 700 800 900 1000
V
SEL
= 5V
V
SEL
= 0V
V
CC
= 5V
T
A
= 25
C
R
PROG
= 1.5k
TEMPERATURE(
C)
4.24
4.22
4.20
4.18
4.16
4.14
4.12
4.10
4.08
4.06
V
BAT
(V)
1733 G02
50
25
0
25
50
75
100
125
V
SEL
= 5V
V
SEL
= 0V
V
CC
= 5V
I
BAT
= 10mA
R
PROG
= 1.5k
V
CC
(V)
4.24
4.22
4.20
4.18
4.16
4.14
4.12
4.10
4.08
4.06
V
BAT
(V)
1733 G03
4.0
4.5
5.0
5.5
6.0
6.5
7.0
V
SEL
= V
CC
V
SEL
= 0V
T
A
= 25
C
I
BAT
= 10mA
R
PROG
= 1.5k
CHARGE CURRENT (mA)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
V
PROG
(V)
1733 G04
0 100 200 300 400 500 600 700 800 900 1000
V
CC
= 5V
T
A
= 25
C
R
PROG
= 1.5k
V
SEL
= 5V
V
BAT
(V)
0
I
BAT
(mA)
1.0
2.0 2.5
4.5
1733 G05
0.5
1.5
3.0 3.5 4.0
1100
1000
900
800
700
600
500
400
300
200
100
0
V
CC
= 5V
T
A
= 25
C
R
PROG
= 1.5k
V
SEL
= 5V
V
CC
(V)
4.0
I
BAT
(mA)
5.0
6.0
6.5
1733 G06
4.5
5.5
7.0
1100
1000
900
800
700
600
500
400
300
200
100
0
V
BAT
= 4.1V
T
A
= 25
C
R
PROG
= 1.5k
V
SEL
= 5V
V
CC
(V)
4.0
I
BAT
(mA)
5.0
6.0
6.5
1733 G07
4.5
5.5
7.0
1100
1000
900
800
700
600
500
400
V
BAT
= 3.5V
T
A
= 25
C
V
SEL
= V
CC
R
PROG
= 1.5k
R
PROG
= 3k
TEMPERATURE (
C)
50
I
BAT
(mA)
0
50
75
1733 G08
25
25
100
1000
900
800
700
600
500
400
300
200
100
0
V
CC
= 5V
V
BAT
= 3.5V
R
PROG
= 1.5k
V
SEL
= 5V
THERMAL CONTROL
LOOP IN OPERATION
Charge Current vs Battery Voltage
Charge Current vs Input Voltage
Charge Current vs V
CC
Charge Current vs Temperature
with Thermal Regulation
TEMPERATURE (
C)
50
25
75
1733 G09
25
0
50
100
I
BAT
(mA)
V
CC
= 5V
V
BAT
= 4V
R
PROG
= 3k
V
SEL
= 5V
535
530
525
520
515
510
505
500
495
490
485
480
475
470
465
LTC1733
5
sn1733 1733fs
Trickle Charge Current vs V
CC
TYPICAL PERFOR A CE CHARACTERISTICS
U
W
PROG Pin Voltage vs Temperature
Constant Current Mode
V
CC
(V)
4.0
5.5
6.5
1733 G10
4.5
5.0
6.0
7.0
V
PROG
(V)
T
A
= 25
C
V
BAT
= 3.5V
R
PROG
= 3k
V
SEL
= 5V
1.515
1.510
1.505
1.500
1.495
1.490
1.485
TEMPERATURE (
C)
50
25
75
1733 G11
25
0
50
100
V
PROG
(V)
V
CC
= 5V
V
BAT
= 4V
R
PROG
= 3k
V
SEL
= 5V
1.515
1.510
1.505
1.500
1.495
1.490
1.485
TEMPERATURE (
C)
50
25
75
1733 G12
25
0
50
100
I
BAT
(mA)
V
CC
= 5V
V
BAT
= 2V
R
PROG
= 1.5k
V
SEL
= 5V
130
120
110
100
90
80
70
V
CC
(V)
4.0
5.5
6.5
1733 G13
4.5
5.0
6.0
7.0
I
BAT
(% OF PROGRAMMED CURRENT)
T
A
= 25
C
V
BAT
= 2V
R
PROG
= 1.5k
V
SEL
= 5V
13
12
11
10
9
8
7
TEMPERATURE(
C)
105
104
103
102
101
100
99
98
97
96
95
t
TIMER
(%)
1733 G14
50
25
0
25
50
75
100
125
V
CC
= 5V
I
BAT
= 0mA
V
SEL
= 5V
C
TIMER
= 0.1
F
105
104
103
102
101
100
99
98
97
96
95
t
TIMER
(%)
1733 G15
T
A
= 25
C
I
BAT
= 0mA
V
SEL
= 5V
C
TIMER
= 0.1
F
V
CC
(V)
4.0
5.5
6.5
4.5
5.0
6.0
7.0
PROG Pin Voltage vs V
CC
Constant Current Mode
Trickle Charge Current vs
Temperature
Timer Accuracy vs Temperature
Timer Accuracy vs V
CC
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