LTC4007-1
4A, High Efficiency,
Li-Ion Battery Charger
FeaTures
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DescripTion
The
LTC
®
4007-1
is a constant-current/constant-voltage
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
generate audible noise even when using ceramic capaci-
tors. Charging current is programmable to ±4% accuracy
using a programming resistor. Charging current can also be
monitored 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, pro-
grammed by an external resistor, sets the total charge time.
The LTC4007-1 includes a thermistor input, which
suspends charging if an unsafe temperature condition
is detected. If the cell voltage is less than 3.25V, 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 condition persists for more than 1/4 of
the total charge time.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
No R
SENSE
is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
Protected by U.S. Patents including 5723970.
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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 4mm
×
5mm QFN Package
applicaTions
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Notebook Computers
Portable Instruments
Battery-Backup Systems
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
20µF
Q1
Q2
3.01k
3.01k
0.0047µF
26.7k
CHARGING
CURRENT
MONITOR
Q1: Si4431BDY
Q2: FDC645N
10µH
0.025
Li-Ion
BATTERY
TGATE
BGATE
PGND
CSP
BAT
PROG
ITH
GND
6.04k
0.12µF
20µF
15nF
0.025
SYSTEM
LOAD
INPUT SWITCH
0.1µF
4.99k
PART
LTC4007-1
LTC4007
AUTO
RESTART
NO
YES
LOW BATTERY
THRESHOLD (Per Cell)
(4.2V/4.1V)
3.25V/3.173V
2.5V/2.44V
LTC4007-1 CLN
THERMISTOR
10k
NTC
40071 TA01
40071fa
For more information
www.linear.com/LTC4007-1
1
LTC4007-1
absoluTe MaxiMuM raTings
(Note 1)
pin conFiguraTion
TOP VIEW
BGATE
19 NC
18 PGND
17 TGATE
25
16 CLN
15 CLP
14
FLAG
8
ITH
9 10 11 12
CSP
I
CL
PROG
BAT
13 CHEM
SHDN
INFET
DCIN
CHG
ACP 1
R
T
2
FAULT
3
GND 4
3C4C 5
LOBAT
6
NTC 7
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 125°C
24 23 22 21 20
UFD PACKAGE
24-LEAD (4mm
×
5mm) PLASTIC QFN
T
JMAX
= 125°C,
θ
JA
= 90°C/W
EXPOSED PAD (PIN 25), GND AND PGND SHOULD BE CONNECTED
TOGETHER WITH A LOW OHMIC CONNECTION
orDer inForMaTion
LEAD FREE FINISH
LTC4007EUFD-1#PBF
TAPE AND REEL
http://www.linear.com/product/LTC4007-1#orderinfo
PART MARKING
40071
PACKAGE DESCRIPTION
24-Lead Plastic QFN
TEMPERATURE RANGE
–40°C to 85°C
LTC4007EUFD-1#TRPBF
Consult LTC 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.
elecTrical characTerisTics
SYMBOL PARAMETER
DCIN Operating Range
I
Q
V
TOL
I
TOL
Operating Current
Charge Voltage Accuracy
Charge Current Accuracy (Note 3)
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DCIN
= 20V, V
BAT
= 12V unless otherwise noted.
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
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l
MIN
6
TYP
3
MAX
28
5
0.8
1.0
4
5
UNITS
V
mA
%
%
%
%
%
%
ms
µA
µA
V
V
40071fa
–0.8
–1.0
–4
–5
V
BAT
< 6V, V
CSP
– V
BAT
Target = 10mV
6V ≤ V
BAT
≤ V
LOBAT
, V
CSP
– V
BAT
Target = 10mV
T
SAMPLE
Shutdown
Battery Leakage Current
UVLO
Undervoltage Lockout Threshold
Shutdown Threshold at SHDN
DCIN = 0V
SHDN = 3V
DCIN Rising, V
BAT
= 0
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l
±60
±35
Measured Sample Time
R
RT
= 1190k
l
42
20
4.7
1.6
60
35
10
5.5
2.5
–10
4.2
1
2
For more information
www.linear.com/LTC4007-1
LTC4007-1
elecTrical characTerisTics
SYMBOL PARAMETER
SHDN Pin Current
Operating Current in Shutdown
Current Sense Amplifier, CA1
Input Bias Current Into BAT Pin
CMSL
CMSH
I
TMAX
I
TREV
CA1/I
1
Input Common Mode Low
CA1/I
1
Input Common Mode High
Maximum Current Sense Threshold (V
CSP
– V
BAT
) V
ITH
= 2.5V
Reverse Current Threshold (V
CSP
– V
BAT
)
Transconductance
Source Current
Sink Current
Current Limit Amplifier
Transconductance
V
CLP
I
CLP
Current Limit Threshold
CLP Input Bias Current
Transconductance
Sink Current
OVSD
Overvoltage Shutdown Threshold as a Percent of
Programmed Charger Voltage
DCIN Detection Threshold (V
DCIN
– V
CLN
)
Forward Regulation Voltage (V
DCIN
– V
CLN
)
Reverse Voltage Turn-Off Voltage (V
DCIN
– V
CLN
) DCIN Voltage Ramping Down
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
LBTOL
FLAG
(C/10) Accuracy
LOBAT
Threshold Accuracy
Voltage Falling at PROG
3C4C = 0V, CHEM = 0V
3C4C = 0V, CHEM = Open
3C4C = Open, CHEM = 0V
3C4C = Open, CHEM = Open
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The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
DCIN
= 20V, V
BAT
= 12V unless otherwise noted.
CONDITIONS
V
SHDN
= 0V, Sum of Current from CLP,
CLN, DCIN
MIN
TYP
–10
2
3
MAX
UNITS
µA
mA
11.67
0
V
CLN
– 0.2
140
165
–30
1
Measured at I
TH
, V
ITH
= 1.4V
Measured at I
TH
, V
ITH
= 1.4V
–40
40
1.4
93
100
100
1
Measured at I
TH
, V
ITH
= 1.4V
l
µA
V
V
mV
mV
mmho
µA
µA
mmho
107
mV
nA
mmho
µA
110
%
Current Comparators I
CMP
and I
REV
l
200
Current Sense Amplifier, CA2
Voltage Error Amplifier, EA
36
102
107
Input P-Channel FET Driver (INFET)
DCIN Voltage Ramping Up
from V
CLN
– 0.1V
l
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0
0.17
25
0.25
50
6.5
0.25
V
mV
mV
V
V
V
–60
5
–25
5.8
I
INFET
= 1µA
I
INFET
= –25µA
4.5
V
NTC
Rising
V
NTC
Falling
V
NTC
≤ 10V
0.375
9.233
9.458
12.311
12.610
83
0.397
9.519
9.750
12.692
13.000
93
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NTCVR
•
0.48
NTCVR
•
0.115
NTCVR
•
0.5
NTCVR
•
0.125
NTCVR
•
0.52
NTCVR
•
0.135
10
0.420
9.805
10.043
13.074
13.390
1O5
V
V
µA
V
V
V
V
V
mV
40071fa
I
CL
Threshold Accuracy
For more information
www.linear.com/LTC4007-1
3
LTC4007-1
elecTrical characTerisTics
SYMBOL PARAMETER
V
OL
V
OH
I
OFF
I
PO
Low Logic Level of ACP,
CHG, FLAG, LOBAT,
I
CL
,
FAULT
High Logic Level of
CHG, LOBAT,
I
CL
Off State Leakage Current of ACP,
FLAG, FAULT
Pull-Up Current on
CHG, LOBAT,
I
CL
Timer Defeat Threshold at CHG
Programming Inputs (CHEM and 3C4C)
V
IH
V
IL
I
PI
Oscillator
f
OSC
f
MIN
DC
MAX
Regulator Switching Frequency
Regulator Switching Frequency in Drop Out
Regulator Maximum Duty Cycle
V
TGATE
High (V
CLN
– V
TGATE
)
V
BGATE
High
V
TGATE
Low (V
CLN
– V
TGATE
)
V
BGATE
Low
TGTR
TGTF
BGTR
BGTF
TGATE Transition Time
TGATE Rise Time
TGATE Fall Time
BGATE Transition Time
BGATE Rise Time
BGATE Fall Time
V
TGATE
at Shutdown (V
CLN
– V
TGATE
)
V
BGATE
at Shutdown
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
50
50
40
40
4.5
4.5
5.6
5.6
255
20
98
300
25
99
50
10
10
50
110
100
90
80
100
100
345
kHz
kHz
%
mV
V
V
mV
ns
ns
ns
ns
mV
mV
High Logic Level
Low Logic Level
Pull-Up Current
V = 0V
l
l
The
l
denotes the specifications which apply over the full operating
temperature range, 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
1
3.3
1
–14
l
l
MIN
TYP
MAX
0.5
UNITS
V
V
2.7
–1
–10
1
µA
µA
V
V
V
µA
Gate Drivers (TGATE, BGATE)
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
See Test Circuit.
Note 3:
Does not include tolerance of current sense resistor or current
programming resistor.
Note 4:
The LTC4007E-1 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.
4
40071fa
For more information
www.linear.com/LTC4007-1
LTC4007-1
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
40071 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)
40071 G03
40071 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
)
40071 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)
40071 G05
DCIN = 20V
V
FLOAT
= 12.6V
40071 G06
1A Load Step
(Battery Not Present)
40
BATTERY LEAKAGE CURRENT (µA)
35
30
25
20
15
10
5
0
DCIN = 20V
V
FLOAT
= 12.6V
40071 G07
Battery Leakage Current vs
Battery Voltage
VDCIN = 0V
CHARGER CURRENT (500mA/DIV)
OUTPUT VOLTAGE (5V/DIV)
0
5
10
15
20
BATTERY VOLTAGE (V)
25
30
40071 G08
40071fa
For more information
www.linear.com/LTC4007-1
5
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