LTC4007
4A, High Efficiency,
Standalone Li-Ion Battery Charger
FEATURES
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DESCRIPTION
The
LTC
®
4007
is a complete constant-current/constant-volt-
age charger controller for 3- or 4-cell lithium-ion batteries.
The PWM controller uses a synchronous, quasi-constant
frequency, constant off-time architecture that will not gen-
erate audible noise even when using ceramic capacitors.
Charging current is programmable to ±4% accuracy using
a programming resistor. Charging current can also be mon-
itored as a voltage across the programming resistor.
The output float voltage is pin programmed for cell count
(3 cells or 4 cells) and chemistry (4.2V/4.1V). A timer,
programmed by an external resistor, sets the charge ter-
mination time. Charging is automatically restarted when
cell voltage falls below 3.9V/cell.
LTC4007 includes a thermistor input, which suspends
charging if an unsafe temperature condition is detected.
If the cell voltage is less than 2.5V, a low-battery indicator
asserts and can be used to program a trickle charge current
to safely charge depleted batteries. The
FAULT
pin is also
asserted and charging terminates if the low-battery con-
dition persists for more than 1/4 of the total charge time.
All registered trademarks and trademarks are the property of their respective owners. All other
trademarks are the property of their respective owners. Protected by U.S. Patents including
5723970.
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Complete Charger Controller for 3- or 4-Cell
Lithium-Ion Batteries
High Conversion Efficiency: Up to 96%
Output Currents Exceeding 4A
±0.8% Charging Voltage Accuracy
Built-In Charge Termination for Li-Ion Batteries
AC Adapter Current Limiting Maximizes Charge Rate*
Thermistor Input for Temperature Qualified Charging
Wide Input Voltage Range: 6V to 28V
0.5V Dropout Voltage; Maximum Duty Cycle: 98%
Programmable Charge Current: ±4% Accuracy
Indicator Outputs for Charging, C/10 Current Detection,
AC Adapter Present, Low Battery, Input Current
Limiting and Faults
Charging Current Monitor Output
Available in a 24-Pin Narrow SSOP Package
APPLICATIONS
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Notebook Computers
Portable Instruments
Battery-Backup Systems
Standalone Li-Ion Chargers
TYPICAL APPLICATION
12.6V, 4A Li-Ion Battery Charger
DCIN
0V TO 28V
V
LOGIC
100k
LOBAT
I
CL
ACP
SHDN
FAULT
CHG
FLAG
32.4k
100k
100k
3C4C
CHEM
LOBAT
I
CL
ACP
SHDN
FAULT
CHG
FLAG
NTC
R
T
0.47µF
309k
TIMING RESISTOR
(~2 HOURS)
DCIN
INFET
CLP
TGATE
BGATE
PGND
CSP
BAT
PROG
ITH
GND
6.04k
0.12µF
0.0047µF
26.7k
Q1: Si4431DY
Q2: FDC6459
3.01k
3.01k
CHARGING
CURRENT
MONITOR
Q2
20µF
INPUT SWITCH
0.1µF
4.99k
15nF
0.025
20µF
Q1
10µH
0.025
Li-Ion
BATTERY
SYSTEM
LOAD
LTC4007 CLN
THERMISTOR
10k
NTC
4007 TA01
Rev D
Document Feedback
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1
LTC4007
ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW
DCIN
CHG
ACP
R
T
FAULT
GND
3C4C
LOBAT
NTC
1
2
3
4
5
6
7
8
9
24 SHDN
23 INFET
22 BGATE
21 PGND
20 TGATE
19 CLN
18 CLP
17
FLAG
16 CHEM
15 BAT
14 CSP
13 I
CL
Voltage from DCIN, CLP, CLN to GND ......... +32V/–0.3V
PGND with Respect to GND .................................. ±0.3V
CSP, BAT to GND ......................................... +28V/–0.3V
CHEM, 3C4C, R
T
to GND ................................ +7V/–0.3V
NTC .............................................................. +10V/–0.3V
ACP, SHDN,
CHG, FLAG,
FAULT, LOBAT,
I
CL
........................................ +32V/–0.3V
CLP to CLN ............................................................±0.5V
Operating Ambient Temperature Range
(Note 4) ............................................. –40°C to 85°C
Operating Junction Temperature ........... –40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
ITH 10
PROG 11
NC 12
GN PACKAGE
24-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 88°C/W
ORDER INFORMATION
LEAD FREE FINISH
LTC4007EGN#PBF
TAPE AND REEL
LTC4007EGN#TRPBF
http://www.linear.com/product/LTC4007#orderinfo
PART MARKING
LTC4007EGN
PACKAGE DESCRIPTION
24-Lead Plastic SSOP
TEMPERATURE RANGE
–40°C to 85°C
Consult ADI Marketing for parts specified with wider operating temperature ranges.
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/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
The
l
denotes the specifications which apply over the full operating
temperature range (Note 4), otherwise specifications are at T
A
= 25°C. V
DCIN
= 20V, V
BAT
= 12V unless otherwise noted.
SYMBOL PARAMETER
DCIN Operating Range
Operating Current
I
Q
Charge Voltage Accuracy
V
TOL
I
TOL
Charge Current Accuracy (Note 3)
CONDITIONS
Sum of Current from CLP, CLN , DCIN
Nominal Values: 12.3V, 12.6V, 16.4V,
16.8V (Note 2)
V
CSP
– V
BAT
Target = 100mV
V
BAT
< 6V, V
CSP
– V
BAT
Target = 10mV
6V ≤ V
BAT
≤ V
LOBAT
, V
CSP
– V
BAT
Target = 10mV
R
RT
= 270k
DCIN = 0V
SHDN = 3V
DCIN Rising, V
BAT
= 0
MIN
6
–0.8
–1.0
–4
–5
–60
–35
–15
15
4.7
1.6
–10
2
TYP
3
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ELECTRICAL CHARACTERISTICS
MAX
28
5
0.8
1.0
4
5
60
35
15
35
10
5.5
2.5
3
UNITS
V
mA
%
%
%
%
%
%
%
µA
µA
V
V
µA
mA
Rev D
T
TOL
Termination Timer Accuracy
Shutdown
Battery Leakage Current
UVLO
Undervoltage Lockout Threshold
Shutdown Threshold at SHDN
SHDN Pin Current
Operating Current in Shutdown
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–10
4.2
1
V
SHDN
= 0V, Sum of Current from CLP,
CLN, DCIN
2
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LTC4007
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
Current Sense Amplifier, CA1
Input Bias Current Into BAT Pin
CMSL
CA1/I
1
Input Common Mode Low
CMSH
CA1/I
1
Input Common Mode High
Current Comparators I
CMP
and I
REV
I
TMAX
Maximum Current Sense Threshold (V
CSP
– V
BAT
)
Reverse Current Threshold (V
CSP
– V
BAT
)
I
TREV
Current Sense Amplifier, CA2
Transconductance
Source Current
Sink Current
Current Limit Amplifier
Transconductance
Current Limit Threshold
V
CLP
CLP Input Bias Current
I
CLP
Voltage Error Amplifier, EA
Transconductance
Sink Current
OVSD
Overvoltage Shutdown Threshold as a Percent of
Programmed Charger Voltage
Input P-Channel FET Driver (INFET)
DCIN Detection Threshold (V
DCIN
– V
CLN
)
Forward Regulation Voltage (V
DCIN
– V
CLN
)
Reverse Voltage Turn-Off Voltage (V
DCIN
– V
CLN
)
INFET “On” Clamping Voltage (V
DCIN
– V
INFET
)
INFET “Off” Clamping Voltage (V
DCIN
– V
INFET
)
Thermistor
NTCVR Reference Voltage During Sample Time
High Threshold
Low Threshold
Thermistor Disable Current
Indicator Outputs (ACP,
CHG, FLAG, LOBAT,
I
CL
,
FAULT
C10TOL
FLAG
(C/10) Accuracy
LBTOL
LOBAT
Threshold Accuracy
The
l
denotes the specifications which apply over the full operating
temperature range (Note 4), otherwise specifications are at T
A
= 25°C. V
DCIN
= 20V, V
BAT
= 12V unless otherwise noted.
CONDITIONS
MIN
TYP
11.67
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MAX
UNITS
µA
V
V
mV
mV
mmho
µA
µA
mmho
mV
nA
mmho
µA
%
0
V
CLN
– 0.2
140
165
–30
1
–40
40
1.4
100
100
1
36
107
200
V
ITH
= 2.5V
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Measured at I
TH
, V
ITH
= 1.4V
Measured at I
TH
, V
ITH
= 1.4V
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93
107
Measured at I
TH
, V
ITH
= 1.4V
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102
110
DCIN Voltage Ramping Up
from V
CLN
– 0.1V
DCIN Voltage Ramping Down
I
INFET
= 1µA
I
INFET
= –25µA
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0
0.17
25
–25
5.8
0.25
50
6.5
0.25
V
mV
mV
V
V
V
V
V
µA
V
V
V
V
V
V
V
V
V
mV
–60
5
V
NTC
Rising
V
NTC
Falling
V
NTC
≤ 10V
Voltage Falling at PROG
3C4C = 0V, CHEM = 0V
3C4C = 0V, CHEM = Open
3C4C = Open, CHEM = 0V
3C4C = Open, CHEM = Open
3C4C = 0V, CHEM = 0V
3C4C = 0V, CHEM = Open
3C4C = Open, CHEM = 0V
3C4C = Open, CHEM = Open
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NTCVR
• 0.48
NTCVR
• 0.115
4.5
NTCVR
• 0.5
NTCVR
• 0.125
NTCVR
• 0.52
NTCVR
• 0.135
10
0.420
7.52
7.71
10.10
10.28
11.65
11.94
15.54
15.92
1O5
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RESTART Threshold Accuracy
I
CL
Threshold Accuracy
0.375
7.10
7.27
9.46
9.70
11.13
11.40
14.84
15.20
83
0.397
7.32
7.50
9.76
10
11.42
11.70
15.23
15.60
93
Rev D
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3
LTC4007
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
Low Logic Level of ACP,
CHG, FLAG, LOBAT,
V
OL
I
CL
,
FAULT
High Logic Level of
CHG, LOBAT,
I
CL
V
OH
Off State Leakage Current of ACP,
FLAG, FAULT
I
OFF
Pull-Up Current on
CHG, LOBAT,
I
CL
I
PO
Charge Termination Defeat Threshold at CHG
Programming Inputs (CHEM and 3C4C)
High Logic Level
V
IH
Low Logic Level
V
IL
Pull-Up Current
I
PI
Oscillator
Regulator Switching Frequency
f
OSC
Regulator Switching Frequency in Drop Out
f
MIN
DC
MAX
Regulator Maximum Duty Cycle
Gate Drivers (TGATE, BGATE)
V
TGATE
High (V
CLN
– V
TGATE
)
V
BGATE
High
V
TGATE
Low (V
CLN
– V
TGATE
)
V
BGATE
Low
TGATE Transition Time
TGTR
TGATE Rise Time
TGTF
TGATE Fall Time
BGATE Transition Time
BGTR
BGATE Rise Time
BGTF
BGATE Fall Time
V
TGATE
at Shutdown (V
CLN
– V
TGATE
)
V
BGATE
at Shutdown
The
l
denotes the specifications which apply over the full operating
temperature range (Note 4), otherwise specifications are at T
A
= 25°C. V
DCIN
= 20V, V
BAT
= 12V unless otherwise noted.
CONDITIONS
I
OL
= 100µA
I
OH
= –1µA
V
OH
= 3V
V = 0V
MIN
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TYP
MAX
0.5
UNITS
V
V
µA
µA
V
V
V
µA
kHz
kHz
%
mV
V
V
mV
ns
ns
ns
ns
mV
mV
2.7
–1
–10
1
1
l
l
3.3
1
–14
255
20
98
300
25
99
345
V = 0V
Duty Cycle ≥ 98%
V
CSP
= V
BAT
I
TGATE
= –1mA
C
LOAD
= 3000pF
C
LOAD
= 3000pF
I
BGATE
= 1mA
C
LOAD
= 3000pF, 10% to 90%
C
LOAD
= 3000pF, 10% to 90%
C
LOAD
= 3000pF, 10% to 90%
C
LOAD
= 3000pF, 10% to 90%
I
TGATE
= –1µA, DCIN = 0V, CLN = 12V
I
BGATE
= 1µA, DCIN = 0V, CLN = 12V
4.5
4.5
5.6
5.6
50
10
10
50
110
100
90
80
100
100
50
50
40
40
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:
See "Test Circuit".
Note 3:
Does not include tolerance of current sense resistor or current
programming resistor.
Note 4:
The LTC4007E 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.
Rev D
4
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LTC4007
TYPICAL PERFORMANCE CHARACTERISTICS
INFET Response Time to
Reverse Current
V
gs
= 0
V
gs
OF PFET (2V/DIV)
0.10
0.05
–0.05
V
OUT
ERROR (%)
–0.10
–0.15
–0.20
–0.25
–0.30
I
d
(REVERSE) OF
PFET (5A/DIV)
I
d
= 0A
1.25µs/DIV
TEST PERFORMED ON DEMOBOARD
V
CHARGE
= 12.6V
V
IN
= 15VDC
CHARGER = ON
PFET = 1/2 Si4925DY
I
CHARGE
= <10mA
4007 G01
–0.35
–0.40
–0.45
13
15
17
19
21 23 25
VDCIN (V)
27
29
31
C3C4 = GND
C3C4 = OPEN
V
s
OF PFET (5V/DIV)
OUTPUT VOLTAGE ERROR (%)
0
Line Regulation
0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
–3.5
–4.0
–4.5
–5.0
V
OUT
vs I
OUT
V
s
= 0V
3C4C = GND
3C4C = OPEN
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
OUTPUT CURRENT (A)
4007 G03
4007 G02
PWM Frequency vs Duty Cycle
350
300
PWM FREQUENCY (kHz)
250
200
150
100
50
0
PROGRAMMED CURRENT = 10%
DCIN = 15V
DCIN = 20V
DCIN = 24V
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
DUTY CYCLE (V
OUT
/V
IN
)
4007 G04
Disconnect/Reconnect Battery
(Load Dump)
3A STEP
1A Load Step (Battery Present)
CHARGER CURRENT (1A/DIV)
V
FLOAT
1V/DIV
1A STEP
1A STEP
LOAD
STATE
3A STEP
DISCONNECT
RECONNECT
OUTPUT VOLTAGE (500mV/DIV)
LOAD CURRENT = 1A, 2A, 3A
DCIN = 20V
V
FLOAT
= 12.6V (3C4C = GND, CHEM = OPEN)
4007 G05
DCIN = 20V
V
FLOAT
= 12.6V
4007 G06
1A Load Step
(Battery Not Present)
40
BATTERY LEAKAGE CURRENT (µA)
35
30
25
20
15
10
5
0
Battery Leakage Current
vs Battery Voltage
VDCIN = 0V
CHARGER CURRENT (500mA/DIV)
OUTPUT VOLTAGE (5V/DIV)
DCIN = 20V
V
FLOAT
= 12.6V
4007 G07
0
5
10
15
20
BATTERY VOLTAGE (V)
25
30
4007 G08
Rev D
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5
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