LTC4002
Standalone Li-Ion
Switch Mode Battery Charger
FEATURES
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DESCRIPTIO
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Wide Input Supply Range:
4.7V to 22V – 4.2 Version
8.9V to 22V – 8.4 Version
High Efficiency Current Mode PWM Controller with
500kHz Switching Frequency
±1%
Charge Voltage Accuracy
End-of-Charge Current Detection Output
3 Hour Charge Termination Timer
Constant Switching Frequency for Minimum Noise
±5%
Charge Current Accuracy
Low 10µA Reverse Battery Drain Current
Automatic Battery Recharge
Automatic Shutdown When Input Supply is Removed
Automatic Trickle Charging of Low Voltage Batteries
Battery Temperature Sensing and Charge
Qualification
Stable with Ceramic Output Capacitor
8-Lead SO and 10-Lead DFN Packages
The LTC
®
4002 is a complete battery charger controller for
one (4.2V) or two (8.4V) cell lithium-ion batteries. With a
500kHz switching frequency, the LTC4002 provides a
small, simple and efficient solution to fast charge Li-Ion
batteries from a wide range of supply voltages. An external
sense resistor sets the charge current with
±5%
accuracy.
An internal resistor divider and precision reference set the
final float voltage to 4.2V per cell with
±1%
accuracy.
When the input supply is removed, the LTC4002 automati-
cally enters a low current sleep mode, dropping the battery
drain current to 10µA. An internal comparator detects the
near end-of-charge condition while an internal timer sets
the total charge time and terminates the charge cycle. After
the charge cycle ends, if the battery voltage drops below
4.05V per cell, a new charge cycle will automatically begin.
The LTC4002 is available in the 8-lead SO and 10-lead DFN
packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
APPLICATIO S
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Portable Computers
Charging Docks
Handheld Instruments
TYPICAL APPLICATIO
1.5A Single Cell Li-Ion Battery Charger
V
IN
5V TO 22V
100
90
0.1µF
BAT
2k
V
CC
GATE
LTC4002ES8-4.2
10µF
EFFICIENCY (%)
80
CHARGE
STATUS
CHRG
SENSE
6.8µH
70
68mΩ
COMP
NTC
BAT
GND
22µF
10k
T
NTC
NTC: DALE NTHS-1206N02
60
5
10
15
INPUT VOLTAGE (V)
4002 TA02
0.47µF
2.2k
+
Li-Ion
BATTERY
4002 TA01
U
Efficiency vs Input Voltage
(CURVES INCLUDE
INPUT DIODE)
V
BAT
= 4V
V
BAT
= 3.8V
20
25
U
U
4002f
1
LTC4002
ABSOLUTE
AXI U RATI GS
(Note 1)
Operating Temperature Range (Note 4) .. – 40°C to 85°C
Storage Temperature Range ................. – 65°C to 125°C
Lead Temperature (S8 Package)
(Soldering, 10 sec) ........................................... 300°C
Supply Voltage (V
CC
) .............................................. 24V
GATE .................................................. (V
CC
– 8V) to V
CC
BAT, SENSE .............................................. – 0.3V to 14V
CHRG, NTC ................................................. – 0.3V to 8V
PACKAGE/ORDER I FOR ATIO
TOP VIEW
COMP
V
CC
GATE
PGND
SGND
1
2
3
4
5
11
10 NC
9 NTC
8 SENSE
7 BAT
6 CHRG
ORDER PART
NUMBER
LTC4002EDD-4.2
LTC4002EDD-8.4
DD PART MARKING
LAGG
LBGY
COMP 1
V
CC
2
GATE 3
GND 4
DD PACKAGE
10-LEAD (3mm
×
3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 43°C/W
EXPOSED PAD IS GND (PIN 11)
MUST BE SOLDERED TO PCB
Consult LTC Marketing for parts specified with wider operating temperature ranges.
(LTC4002-4.2) The
●
denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 10V unless otherwise noted.
SYMBOL
V
CC
I
CC
PARAMETER
V
CC
Supply Voltage
V
CC
Supply Current
Current Mode
Shutdown Mode
Sleep Mode
5V
≤
V
CC
≤
22V (Note 2)
●
ELECTRICAL CHARACTERISTICS
CONDITIONS
●
DC Characteristics
4.7
3
3
10
4.168
4.158
93
90
5
2.75
3.9
200
4.2
100
10
2.9
4.2
200
COMP Pin Falling
V
CC
– V
BAT
V
COMP
= 1.2V
V
CHRG
= 1V
I
CHRG
= 1mA
V
SNS(EOC)
/V
SNS(CHG)
10
15
360
250
100
25
0.15
25
35
0.3
32
10
500
22
5
5
20
4.232
4.242
107
110
15
3.05
4.5
V
mA
mA
µA
V
V
mV
mV
mV
V
V
mV
mV
mV
µA
µA
V
%
%
4002f
V
BAT(FLT)
Battery Regulated Float Voltage
V
SNS(CHG)
Constant Current Sense Voltage
V
SNS(TRKL)
Trickle Current Sense Voltage
V
TRKL
V
UV
∆V
UV
V
MSD
V
ASD
I
COMP
I
CHRG
V
CHRG
R
EOC
t
TIMER
Trickle Charge Threshold Voltage
V
CC
Undervoltage Lockout Threshold Voltage
V
CC
Undervoltage Lockout Hysteresis Voltage
Manual Shutdown Threshold Voltage
Automatic Shutdown Threshold Voltage
COMP Pin Output Current
CHRG Pin Weak Pull-Down Current
CHRG Pin Output Low Voltage
End-of-Charge Ratio
Charge Time Accuracy
3V
≤
V
BAT
≤
4V (Note 3)
V
BAT
= 0V (Note 3)
V
BAT
Rising
V
CC
Rising
2
U
U
W
W W
U
W
TOP VIEW
8
7
6
5
NTC
SENSE
BAT
CHRG
ORDER PART
NUMBER
LTC4002ES8-4.2
LTC4002ES8-8.4
S8 PART MARKING
400242
400284
S8 PACKAGE
8-LEAD PLASTIC SO
T
JMAX
= 125°C,
θ
JA
= 110°C/W
MIN
TYP
MAX
UNITS
0°C
≤
T
A
≤
85°C
–40°C
≤
T
A
≤
85°C
●
●
LTC4002
(LTC4002-4.2) The
●
denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 10V unless otherwise noted.
SYMBOL
I
NTC
V
NTC-HOT
PARAMETER
NTC Pin Output Current
NTC Pin Threshold Voltage (Hot)
CONDITIONS
V
NTC
= 0.85V
V
NTC
Falling
Hysteresis
V
NTC
Rising
Hysteresis
V
BAT(FULLCHARGED)
– V
RECHRG
, V
BAT
Falling
V
CHRG
= 8V, Charging Stops
450
500
●
●
●
ELECTRICAL CHARACTERISTICS
MIN
75
340
2.428
100
TYP
85
355
25
2.465
170
150
MAX
95
370
2.502
200
1
550
100
UNITS
µA
mV
mV
V
mV
mV
µA
kHz
%
ns
ns
V
NTC-COLD
NTC Pin Threshold Voltage (Cold)
∆V
RECHRG
Recharge Battery Voltage Offset from Full
Charged Battery Voltage
I
LEAK
Oscillator
f
OSC
DC
Gate Drive
t
r
t
f
∆V
GATE
∆V
GATEHI
∆V
GATELO
Rise Time
Fall Time
Output Clamp Voltage
Output High Voltage
Output Low Voltage
Switching Frequency
Maximum Duty Cycle
CHRG Pin Leakage Current
C
GATE
= 2000pF, 10% to 90%
C
GATE
= 2000pF, 90% to 10%
V
CC
– V
GATE
, V
CC
≥
9V
∆V
GATEHI
= V
CC
– V
GATE
, V
CC
≥
7V
∆V
GATELO
= V
CC
– V
GATE
, V
CC
≥
7V
●
●
●
20
50
8
0.3
4.5
V
V
V
(LTC4002-8.4) The
●
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at
T
A
= 25°C. V
CC
= 12V unless otherwise noted.
SYMBOL
V
CC
I
CC
PARAMETER
V
CC
Supply Voltage
V
CC
Supply Current
Current Mode
Shutdown Mode
Sleep Mode
9V
≤
V
CC
≤
22V (Note 2)
●
CONDITIONS
●
MIN
8.9
TYP
MAX
22
UNITS
V
mA
mA
µA
V
V
mV
mV
mV
V
V
mV
mV
mV
µA
DC Characteristics
3
3
10
8.336
8.316
95
93
5
4.7
8.4
100
100
10
5
7.5
500
COMP Pin Falling
V
CC
– V
BAT
V
COMP
= 1.2V
V
CHRG
= 1V
I
CHRG
= 1mA
V
SNS(EOC)
/V
SNS(CHG)
V
NTC
= 0.85V
●
5
5
20
8.464
8.484
105
107
15
5.3
8.5
500
V
BAT(FLT)
Battery Regulated Float Voltage
V
SNS(CHG)
Constant Current Sense Voltage
6V
≤
V
BAT
≤
8V (Note 3)
V
SNS(TRKL)
Trickle Current Sense Voltage
V
TRKL
V
UV
∆V
UV
V
MSD
V
ASD
I
COMP
I
CHRG
V
CHRG
R
EOC
t
TIMER
I
NTC
Trickle Charge Threshold Voltage
V
CC
Undervoltage Lockout Threshold Voltage
V
CC
Undervoltage Lockout Hysteresis Voltage
Manual Shutdown Threshold Voltage
Automatic Shutdown Threshold Voltage
COMP Pin Output Current
CHRG Pin Weak Pull-Down Current
CHRG Pin Output Low Voltage
End-of-Charge Ratio
Charge Time Accuracy
NTC Pin Output Current
V
BAT
= 0V (Note 3)
V
BAT
Rising
V
CC
Rising
●
200
350
250
100
15
5
75
25
0.15
10
85
35
0.3
15
10
95
µA
V
%
%
µA
4002f
3
LTC4002
(LTC4002-8.4) The
●
denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 12V unless otherwise noted.
SYMBOL
V
NTC-HOT
PARAMETER
NTC Pin Threshold Voltage (Hot)
CONDITIONS
V
NTC
Falling
Hysteresis
V
NTC
Rising
Hysteresis
V
BAT(FULLCHARGED)
– V
RECHRG
, V
BAT
Falling
V
CHRG
= 8V, Charging Stops
450
500
●
●
ELECTRICAL CHARACTERISTICS
MIN
340
2.428
200
TYP
355
25
2.465
170
300
MAX
370
2.502
400
1
550
100
UNITS
mV
mV
V
mV
mV
µA
kHz
%
ns
ns
V
NTC-COLD
NTC Pin Threshold Voltage (Cold)
∆V
RECHRG
Recharge Battery Voltage Offset from Full
Charged Battery Voltage
I
LEAK
Oscillator
f
OSC
DC
Gate Drive
t
r
t
f
∆V
GATE
∆V
GATEHI
∆V
GATELO
Rise Time
Fall Time
Output Clamp Voltage
Output High Voltage
Output Low Voltage
Switching Frequency
Maximum Duty Cycle
CHRG Pin Leakage Current
C
GATE
= 2000pF, 10% to 90%
C
GATE
= 2000pF, 90% to 10%
V
CC
– V
GATE
∆V
GATEHI
= V
CC
– V
GATE
∆V
GATELO
= V
CC
– V
GATE
●
●
●
20
50
8
0.3
4.5
V
V
V
Note 1:
Absolute Maximum Rating are those values beyond which the life
of a device may be impaired.
Note 2:
The LTC4002 is tested with Test Circuit 1.
Note 3:
The LTC4002 is tested with Test Circuit 2.
Note 4:
The LTC4002 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.
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current vs Temperature
4.0
4
3.5
3
f
OSC
(kHz)
I
CC
(mA)
I
CC
(mA)
3.0
2.5
–50 –25
50
25
75
0
TEMPERATURE (°C)
4
U W
100
4002
G01
T
A
= 25°C, V
CC
= 10V unless otherwise noted.
Oscillator Frequency
vs Temperature
550
Supply Current vs V
CC
CURRENT MODE
500
125
2
5
10
15
V
CC
(V)
20
25
4002 G02
450
– 50 – 25
0
50
75
25
TEMPERATURE (°C)
100
125
4002 G03
4002f
LTC4002
TYPICAL PERFOR A CE CHARACTERISTICS
Oscillator Frequency vs V
CC
510
8
500
V
CHRG
(mV)
f
OSC
(kHz)
V
UV
(V)
490
5
10
15
V
CC
(V)
20
CHRG Pin Output Low Voltage
vs Temperature
180
I
LOAD
= 1mA
29
I
CHRG
(µA)
V
CHG
(mV)
I
CHRG
(µA)
140
100
– 50 – 25
0
50
75
25
TEMPERATURE (°C)
Recharge Voltage Offset
Per Cell from Full Charged
Voltage vs Temperature
190
160
∆V
RECHRG/CELL
(mV)
∆V
RECHRG
(mV)
∆V
RECHRG
(mV)
150
110
– 50 – 25
0
50
75
25
TEMPERATURE (°C)
U W
4002 G04
T
A
= 25°C, V
CC
= 10V unless otherwise noted.
CHRG Pin Output Low Voltage
vs V
CC
150
I
LOAD
= 1mA
Undervoltage Lockout Threshold
vs Temperature
V
CC
RISING
LTC4002-8.4
7
6
140
5
LTC4002-4.2
25
4
– 50 – 25
130
0
50
75
25
TEMPERATURE (°C)
100
125
5
15
V
CC
(V)
4002 G05
4002 G06
10
20
25
CHRG Pin Weak Pull-Down
Current vs Temperature
V
CHRG
= 8V
28
CHRG Output Pin Weak Pull-Down
Current vs V
CC
V
CHRG
= 8V
25
25
100
125
21
– 50 – 25
22
0
50
75
25
TEMPERATURE (°C)
100
125
5
10
15
V
CC
(V)
20
25
4002 G09
4002 G07
4002 G08
Recharge Voltage Offset from Full
Charged Voltage vs V
CC
LTC4002-4.2
Recharge Voltage Offset from Full
Charged Voltage vs V
CC
320
LTC4002-8.4
150
300
100
125
140
280
5
10
15
V
CC
(V)
20
25
4002 G11
5
10
15
V
CC
(V)
20
25
4002 G12
4002 G10
4002f
5
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