LTC4059EDC#TR [Linear]
LTC4059/LTC4059A - 900mA Linear Li-Ion Battery Chargers with Thermal Regulation in 2 x 2 DFN; Package: DFN; Pins: 6; Temperature Range: -40°C to 85°C;
| 型号： | LTC4059EDC#TR |
| 厂家： | 
Linear |
| 描述： | LTC4059/LTC4059A - 900mA Linear Li-Ion Battery Chargers with Thermal Regulation in 2 x 2 DFN; Package: DFN; Pins: 6; Temperature Range: -40°C to 85°C 电池 |
| 文件： | 总12页 (文件大小：219K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC4059/LTC4059A
900mA Linear Li-Ion
Battery Chargers with
Thermal Regulation in 2 × 2 DFN
U
FEATURES
DESCRIPTIO
The LTC®4059/LTC4059A are constant-current/constant-
voltagelinearchargersforsinglecelllithium-ionbatteries.
Their 2mm × 2mm DFN package and low external compo-
nent count make these chargers especially well suited for
portable applications. Furthermore, they are designed to
work within USB power specifications.
■
Programmable Charge Current Up to 900mA
■
Charge Current Monitor Output for Charge
Termination*
■
Constant-Current/Constant-Voltage Operation with
Thermal Regulation to Maximize Charging Rate
Without Risk of Overheating*
■
■
■
Constant-Current Source Mode for Charging
Nickel Batteries (LTC4059 Only)
ACPR Pin Indicates Presence of Input Supply
(LTC4059A Only)
No External MOSFET, Sense Resistor or Blocking
Diode Required
Operating Supply Voltage from 3.75V to 8V
Charges Single Cell Li-Ion Batteries Directly from
USB Port
No external sense resistor, MOSFET or blocking diode is
required. Thermal feedback regulates the charge current
tolimitthedietemperatureduringhighpoweroperationor
high ambient thermal conditions. The charge voltage is
fixed at 4.2V and the charge current is programmable.
■
■
When the input supply (wall adapter or USB supply) is
removed,theLTC4059/LTC4059Aautomaticallyenteralow
currentstate,droppingthebatterycurrentdraintolessthan
1µA. With power applied, they can be put into shutdown
mode, reducing the supply current to 10µA.
■
■
■
Preset 4.2V Charge Voltage with 0.6% Accuracy
10µA Supply Current in Shutdown Mode
Tiny 6-Lead (2mm × 2mm) DFN Package
The LTC4059A features an open-drain status pin to indi-
cate the presence of an input voltage. The LTC4059 can be
used as a constant-current source to charge Nickel cells.
Other features include undervoltage lockout protection
and a current monitor pin which can indicate when to
terminate a charge cycle.
U
APPLICATIO S
■
Wireless PDAs
Cellular Phones
■
■
Portable Electronics
■
The LTC4059/LTC4059A are available in a 6-lead, low
Wireless Headsets
■
Digital Cameras
profile (0.8mm) 2mm × 2mm DFN package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
*US Patent 6,522,118
U
TYPICAL APPLICATIO
Complete Charge Cycle (800mAh Battery)
700
4.4
CONSTANT
CURRENT
CONSTANT
VOLTAGE
V
DD
50k
600
4.2
V
IN
4.5V TO 8V
500
400
300
200
100
0
4.0
3.8
3.6
3.4
3.2
3.0
ACPR
µP
V
CC
LTC4059A
EN
GND PROG
600mA
BAT
1µF
4.2V
Li-Ion
BATTERY
+
2k
V
= 5V
PROG
= 25°C
CC
4059 TA01
R
= 2k
T
A
0
0.5
1
1.5
2
2.5
4059 TA02
TIME (HOURS)
4059fa
1
LTC4059/LTC4059A
W W U W
U
W
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ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
(Note 1)
TOP VIEW
Input Supply Voltage (VCC) ...................... –0.3V to 10V
BAT, PROG, EN, Li CC, ACPR ................... –0.3V to 10V
BAT Short-Circuit Duration ...........................Continuous
BAT Pin Current ............................................... 1000mA
PROG Pin Current............................................. 1000µA
Junction Temperature.......................................... 125°C
Operating Temperature Range (Note 2) .. –40°C to 85°C
Storage Temperature Range ................. –65°C to 125°C
ORDER PART
NUMBER
GND
Li CC/ACPR*
BAT
1
2
3
6
5
4
EN
7
PROG
LTC4059EDC
LTC4059AEDC
V
CC
DC6 PACKAGE
6-LEAD (2mm × 2mm) PLASTIC DFN
DC6 PART
MARKING
TJMAX = 125°C, θJA = 60°C/W TO 85°C/W (NOTE 3)
*Li CC PIN 2 ON LTC4059EDC,
ACPR PIN 2 ON LTC4059AEDC
EXPOSED PAD IS GND (PIN 7)
MUST BE SOLDERED TO PCB
LAFU
LBJH
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 5V unless otherwise noted.
SYMBOL PARAMETER
Supply Voltage
CONDITIONS
MIN
TYP
MAX
8
UNITS
V
V
V
CC
●
●
●
●
3.75
CC
I
I
I
Quiescent V Supply Current
V
V
V
= 4.5V (Forces I
and I
= 0)
25
10
4
60
25
10
µA
CC
CC
BAT
EN
BAT
PROG
V
V
Supply Current in Shutdown
= V
µA
CCMS
CCUV
CC
CC
Supply Current in Undervoltage
< V ; V = 3.5V, V
= 4V
µA
CC
CC
BAT CC
BAT
Lockout
V
V
BAT
Regulated Output Voltage
I
= 2mA
4.175
4.158
4.2
4.2
4.225
4.242
V
V
FLOAT
BAT
4.5V < V < 8V, I
= 2mA
BAT
●
CC
I
BAT Pin Current
R
PROG
R
PROG
= 2.43k, Current Mode, V
= 12.1k, Current Mode, V
= 3.8V
= 3.8V
●
●
475
94
500
100
525
106
mA
mA
BAT
BAT
BAT
I
I
Battery Drain Current in Shutdown
V
V
= V , V > V
BAT
●
●
0
1
±1
µA
µA
BMS
BUV
EN
CC
CC CC
Battery Drain Current in Undervoltage
Lockout
< V , V
= 4V
0
4
BAT BAT
V
V
V
– V
Undervoltage Lockout
V
V
from Low to High, V
from High to Low, V
= 3.7V
= 3.7V
●
●
100
0
150
35
200
80
mV
mV
UV
CC
BAT
CC
CC
BAT
BAT
Threshold
PROG Pin Voltage
R
R
= 2.43k, I
= 12.1k, I
= 500µA
= 100µA
●
●
1.18
1.18
1.21
1.21
1.24
1.24
V
V
PROG
PROG
PROG
PROG
PROG
V
V
Manual Shutdown Threshold
Manual Shutdown Hysteresis
EN Pin Input Resistance
V
V
V
V
V
Increasing
Decreasing
= 5V
●
0.3
0.92
85
1.2
V
mV
MΩ
V
MS
EN
MSHYS
EN
R
●
●
1
1.85
0.92
85
3
EN
EN
V
V
V
Voltage Mode Disable Threshold
Voltage Mode Disable Hysteresis
ACPR Pin Output Low Voltage
Increasing (LTC4059 Only)
Decreasing (LTC4059 Only)
= 300µA (LTC4059A Only)
0.3
1.2
Li CC
Li CCHYS
ACPR
LIM
Li CC
Li CC
ACPR
mV
V
I
0.25
115
0.5
t
Junction Temperature In Constant
Temperature Mode
°C
R
Power FET “ON” Resistance
I
= 150mA
BAT
800
1200
mΩ
ON
(Between V and BAT)
CC
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
operating temperature range are assured by design, characterization and
correlation with statistical process controls.
Note 2: The LTC4059E/LTC4059AE are guaranteed to meet performance
specifications from 0°C to 70°C. Specifications over the –40°C to 85°C
Note 3: Failure to solder the exposed backside of the package to the PC
board ground plane will result in a thermal resistance much higher than
60°C/W.
4059fa
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LTC4059/LTC4059A
U W
TYPICAL PERFOR A CE CHARACTERISTICS
Battery Regulation (Float) Voltage
vs Battery Charge Current
Battery Regulation (Float) Voltage
vs Temperature
Regulated Output (Float) Voltage
vs Supply Voltage
4.24
4.23
4.22
4.21
4.26
4.24
4.22
4.20
4.24
V
I
= 5V
T
I
= 25°C
V
T
= 5V
CC
BAT
R
A
CC
A
R
= 2mA
= 10mA
= 25°C
BAT
4.23
4.22
4.21
= 2.43k
R
= 2.43k
= 2.43k
PROG
PROG
PROG
4.20
4.19
4.18
4.16
4.20
4.19
4.18
4.17
4.16
4.14
4.12
4.10
4.18
4.17
4.16
–25
0
50
–50
75
100
100
200
400
25
5
6
0
500
4
8
300
(mA)
7
TEMPERATURE (°C)
I
V
(V)
BAT
CC
4059 G02
4059 G01
4059 G03
Charge Current vs Ambient
Temperature with Thermal
Regulation
Charge Current vs Input Voltage
Charge Current vs Battery Voltage
600
500
600
500
600
500
400
300
V
T
= 3.85V
Li CC = 5V
LTC4059 ONLY
BAT
A
= 25°C
R
PROG
= 2.43k
R
PROG
= 2.43k
Li CC = 0V
LTC4059A
THERMAL
LIMITING
400
300
400
300
THERMAL CONTROL
LOOP IN OPERATION
200
100
0
200
100
0
200
100
0
R
= 12.1k
PROG
5
R
= 12.1k
50
PROG
25
V
A
R
= 5V
CC
T
= 25°C
V
V
= 5V
BAT
CC
= 2.43k
PROG
= 3.85V
4
6
7
8
2.5
3
3.5
(V)
4
4.5
100 125
–50 –25
0
75
V
CC
(V)
V
BAT
AMBIENT TEMPERATURE (°C)
4059 G04
4059 G05
4059 G06
PROG Pin Voltage
vs Charge Current
PROG Pin Voltage vs Temperature
(Constant Current Mode)
Power FET “ON” Resistance
vs Temperature
1.24
1.23
1.22
1.21
1200
1000
900
800
700
600
500
400
1.4
1.2
V
V
= 5V
BAT
V
T
= 5V
V
I
= 5V
CC
CC
A
R
CC
BAT
= 3.85V
= 25°C
= 100mA
= 2.43k
PROG
1.0
0.8
0.6
0.4
0.2
0
R
= 12.1k
PROG
R
= 2.43k
PROG
1.20
1.19
1.18
50
100 125
–50 –25
0
25
75
100
200
300
(mA)
500
–50
0
25
50
75
100
0
400
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
I
BAT
4059 G08
4059 F07
4059 G09
4059fa
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LTC4059/LTC4059A
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TYPICAL PERFOR A CE CHARACTERISTICS
VCC – VBAT Undervoltage Lockout
Threshold vs Battery Voltage
EN Pin Current
vs EN Voltage and Temperature
UVLO Battery Drain Current
vs Battery Voltage
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
500
450
400
350
300
250
200
150
100
50
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
T
= 25°C
PROG
V
A
= 0V
A
CC
R
= 12.1k
T
= 25°C
T
= 25°C
A
T
= 100°C
A
T
= –20°C
A
0
4
6
1
3
3
4
5
6
7
8
0
1
2
3
5
0
2
4
5
V
(V)
V
EN
(V)
V
BAT
(V)
BAT
4059 G10
4059 G11
4059 G12
UVLO Battery Drain Current
vs Temperature
Manual Shutdown Supply Current
vs Temperature
Manual Shutdown Threshold
Voltage vs Temperature
2.5
2.0
1.5
1.0
0.5
0
1.2
1.1
1.0
0.9
0.8
0.7
0.6
14
12
10
8
V
V
= 0V
= 4V
V
CC
V
EN
= 5V
= 5V
CC
BAT
RISING
6
FALLING
4
2
0
–50 –25
0
25
50
75 100 125
–50
0
25
50
75
100
50
TEMPERATURE (°C)
100 125
–25
–50 –25
0
25
75
TEMPERATURE (°C)
TEMPERATURE (°C)
4059 G13
4059 F15
4059 G14
Voltage Mode Disable Threshold
Voltage vs Temperature
(LTC4059 Only)
ACPR Pin Output Low Voltage
vs Temperature (LTC4059A Only)
ACPR Pin (Pull-Down State)
I-V Curve (LTC4059A Only)
0.50
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
1.2
1.1
1.0
0.9
0.8
0.7
0.6
V
V
I
= 5V
V
V
T
= 5V
BAT
= 25°C
CC
CC
= 4.2V
= 4.2V
BAT
ACPR
0.45
0.40
= 300µA
A
0.35
0.30
0.25
0.20
0.15
RISING
FALLING
0.10
–25
0
50
75 100 125
0
1
2
3
4
5
6
7
8
–50
25
–50
0
25
50
75
100
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
V
ACPR
(V)
4059 G17
4059 G18
4059 F16
4059fa
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LTC4059/LTC4059A
U
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PI FU CTIO S
GND (Pins 1, 7): Ground/Exposed Pad. The exposed
package pad is ground and must be soldered to the PC
board for maximum heat transfer.
PROG (Pin 5): Charge Current Program and Charge Cur-
rent Monitor Pin. Connecting a resistor, RPROG, to ground
programs the charge current. When charging in constant-
current mode, this pin servos to 1.21V. In all modes, the
voltage on this pin can be used to measure the charge
current using the following formula:
Li CC (Pin 2, LTC4059): Li-Ion/Constant Current Input
Pin. Pulling this pin above VLi CC disables voltage mode
thereby providing a constant current to the BAT pin. This
feature is useful for charging Nickel chemistry batteries.
Tie to GND if unused.
VPROG
RPROG
IBAT
=
•1000
ACPR (Pin 2, LTC4059A): Open-Drain Power Supply
Status Output. When VCC is greater than the undervoltage
lockout threshold, the ACPR pin will pull to ground;
otherwise the pin is forced to a high impedance state.
EN (Pin 6): Enable Input Pin. Pulling this pin above the
manual shutdown threshold (VMS is typically 0.92V) puts
theLTC4059inshutdownmode,thusterminatingacharge
cycle.Inshutdownmode,theLTC4059haslessthan25µA
supply current and less than 1µA battery drain current.
Enable is the default state, but the pin should be tied to
GND if unused.
BAT (Pin 3): Charge Current Output. Provides charge
current to the battery and regulates the final float voltage
to 4.2V. An internal precision resistor divider from this pin
sets this float voltage and is disconnected in shutdown
mode.
VCC (Pin 4): Positive Input Supply Voltage. This pin
provides power to the charger. VCC can range from 3.75V
to 8V. This pin should be bypassed with at least a 1µF
capacitor. When VCC is within 35mV of the BAT pin
voltage, the LTC4059 enters shutdown mode, dropping
IBAT to less than 4µA.
4059fa
5
LTC4059/LTC4059A
W
BLOCK DIAGRA
4
V
CC
M2
1×
M1
1000×
EN
LOGIC
6
R
D1
D2
EN
BAT
3
+
–
+
R1
MA
VA
CA
D3
+
+
–
–
REF
1.2V VOLTAGE
REFERENCE
REF
R2
R3
T
–
+
DIE
TA
115°C
PROG
Li CC
GND
5
2
1,7
4059 F01
Figure 1 (LTC4059)
4
V
CC
M2
1×
M1
1000×
EN
LOGIC
6
R
BAT
V
CC
D1
D2
EN
BAT
–
+
3
+
ACPR
–
+
2
R1
MA
VA
CA
D3
+
+
–
–
REF
1.2V VOLTAGE
REFERENCE
REF
R2
R3
T
–
+
DIE
TA
115°C
PROG
GND
5
1,7
4059 F02
Figure 2 (LTC4059A)
4059fa
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LTC4059/LTC4059A
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OPERATIO
The LTC4059/LTC4059A are linear battery chargers de-
signed primarily for charging single cell lithium-ion bat-
teries. Featuring an internal P-channel power MOSFET,
the chargers use a constant-current/constant-voltage
charge algorithm with programmable current. Charge
currentcanbeprogrammedupto900mAwithafinalfloat
voltage accuracy of ±0.6%. No blocking diode or external
sense resistor is required; thus, the basic charger circuit
requires only two external components. The ACPR pin
(LTC4059A) monitors the status of the input voltage with
an open-drain output. The Li CC pin (LTC4059) disables
constant-voltage operation and turns the LTC4059 into a
precisioncurrentsourcecapableofchargingNickelchem-
istry batteries. Furthermore, the LTC4059/LTC4059A are
designed to operate from a USB power source.
benefitofthethermallimitisthatchargecurrentcanbeset
according to typical, not worst-case, ambient tempera-
tures for a given application with the assurance that the
charger will automatically reduce the current in worst-
case conditions.
The charge cycle begins when the voltage at the VCC pin
rises approximately 150mV above the BAT pin voltage, a
program resistor is connected from the PROG pin to
ground, and the EN pin is pulled below the shutdown
threshold (typically 0.85V).
If the BAT pin voltage is below 4.2V, or the Li CC pin is
pulled above VLi CC (LTC4059 only), the LTC4059 will
charge the battery with the programmed current. This is
constant-currentmode. WhentheBATpinapproachesthe
final float voltage (4.2V), the LTC4059 enters constant-
voltage mode and the charge current begins to decrease.
An internal thermal limit reduces the programmed charge
current if the die temperature attempts to rise above a
presetvalueofapproximately115°C. Thisfeatureprotects
the LTC4059/LTC4059A from excessive temperature, and
allows the user to push the limits of the power handling
capabilityofagivencircuitboardwithoutriskofdamaging
the LTC4059/LTC4059A orexternalcomponents. Another
To terminate the charge cycle the EN should be pulled
above the shutdown threshold. Alternatively, reducing the
input voltage below the BAT pin voltage will also terminate
the charge cycle.
W U U
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APPLICATIO S I FOR ATIO
Programming Charge Current
Undervoltage Lockout (UVLO)
The charge current is programmed using a single resistor
from the PROG pin to ground. The battery charge current
is 1000 times the current out of the PROG pin. The
program resistor and the charge current are calculated
using the following equations:
Aninternalundervoltagelockoutcircuitmonitorstheinput
voltageandkeepsthechargerinundervoltagelockoutuntil
VCC risesapproximately150mVabovetheBATpinvoltage.
The UVLO circuit has a built-in hysteresis of 115mV. If the
BAT pin voltage is below approximately 2.75V, then the
charger will remain in undervoltage lockout until VCC rises
above approximately 3V. During undervoltage lockout
conditions, maximum battery drain current is 4µA.
1.21V
ICHG
1.21V
RPROG
RPROG = 1000 •
, ICHG = 1000 •
For best stability over temperature and time, 1% metal-
film resistors are recommended.
Power Supply Status Indicator
(ACPR, LTC4059A Only)
The charge current out of the BAT pin can be determined
at any time by monitoring the PROG pin voltage and using
the following equation:
The power supply status output has two states: pull-down
and high impedance. The pull-down state indicates that
VCC is above the undervoltage lockout threshold (see
Undervoltage Lockout). When this condition is not met,
the ACPR pin is high impedance indicating that the
VPROG
IBAT
=
•1000
RPROG
LTC4059A is unable to charge the battery.
4059fa
7
LTC4059/LTC4059A
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APPLICATIO S I FOR ATIO
Shutdown Mode
ance of the current source pair, M1 and M2 (note that M1
is the internal P-channel power MOSFET). It ensures that
the drain current of M1 is exactly 1000 times greater than
the drain current of M2.
ChargingcanbeterminatedbypullingtheENpinabovethe
shutdown threshold (approximately 0.92V). In shutdown
mode, thebatterydraincurrentisreducedtolessthan1µA
and the supply current to 10µA.
Amplifiers CA and VA are used in separate feedback loops
to force the charger into constant-current or voltage
mode, respectively. Diodes D1 and D2 provide priority to
either the constant-current or constant-voltage loop;
whicheveristryingtoreducethechargecurrentthemost.
The output of the other amplifier saturates low which
effectively removes its loop from the system. When in
constant-current mode, CA servos the voltage at the
PROG pin to be 1.21V. VA servos its inverting input to
precisely 1.21V when in constant-voltage mode and the
internal resistor divider made up of R1 and R2 ensures
that the battery voltage is maintained at 4.2V. The PROG
pin voltage gives an indication of the charge current
during constant-voltage mode as discussed in the Pro-
gramming Charge Current section.
USB and Wall Adapter Power
Although the LTC4059/LTC4059A allow charging from a
USB port, a wall adapter can also be used to charge Li-Ion
batteries. Figure 3 shows an example of how to combine
walladapterandUSBpowerinputs. AP-channelMOSFET,
MP1, isusedtopreventbackconductingintotheUSBport
when a wall adapter is present and Schottky diode, D1, is
used to prevent USB power loss through the 1k pull-down
resistor.
Typically a wall adapter can supply significantly more
current than the 500mA limited USB port. Therefore, an
N-channel MOSFET, MN1, and an extra program resistor
areusedtoincreasethechargecurrentto850mAwhenthe
wall adapter is present.
Transconductance amplifier, TA, limits the die tempera-
ture to approximately 115°C when in constant-tempera-
turemode.TAactsinconjunctionwiththeconstant-current
loop. When the die temperature exceeds approximately
115°C, TA sources current through R3. This causes CA to
reduce the charge current until the PROG pin voltage plus
thevoltageacrossR3equals1.21V.DiodeD3ensuresthat
TA does not affect the charge current when the die tem-
perature is below approximately 115°C. The PROG pin
voltage continues to give an indication of the charge
current.
5V WALL
I
CHG
ADAPTER
3
5
SYSTEM
LOAD
850mA I
CHG
BAT
LTC4059
D1
USB
4
POWER
V
CC
+
Li-Ion
BATTERY
500mA I
MP1
1k
CHG
PROG
3.4k
MN1
2.43k
4059 F03
Figure 3. Combining Wall Adapter and USB Power
In typical operation, the charge cycle begins in constant-
current mode with the current delivered to the battery
equal to 1210V/RPROG. If the power dissipation of the
LTC4059/LTC4059A results in the junction temperature
approaching 115°C, the amplifier (TA) will begin decreas-
ing the charge current to limit the die temperature to
approximately 115°C. As the battery voltage rises, the
LTC4059/LTC4059Aeitherreturntoconstant-currentmode
or enter constant-voltage mode straight from constant-
temperature mode. Regardless of mode, the voltage at the
PROG pin is proportional to the current delivered to the
battery.
Constant Current/Constant Voltage/
Constant Temperature
The LTC4059/LTC4059A use a unique architecture to
charge a battery in a constant-current, constant-voltage
and constant-temperature fashion. Figures 1 and 2 show
simplified block diagrams of the LTC4059 and LTC4059A
respectively. Three of the amplifier feedback loops shown
control the constant-current, CA, constant-voltage, VA,
and constant-temperature, TA modes. A fourth amplifier
feedback loop, MA, is used to increase the output imped-
4059fa
8
LTC4059/LTC4059A
W U U
APPLICATIO S I FOR ATIO
U
Power Dissipation
It is important to remember that LTC4059/LTC4059A
applications do not need to be designed for worst-case
thermal conditions since the IC will automatically reduce
power dissipation when the junction temperature reaches
approximately 115°C.
The conditions that cause the LTC4059/LTC4059A to
reduce charge current through thermal feedback can be
approximated by considering the power dissipated in the
IC. For high charge currents, the LTC4059 power dissipa-
tion is approximately:
Board Layout Considerations
PD = (VCC – VBAT) • IBAT
In order to be able to deliver maximum charge current
under all conditions, it is critical that the exposed metal
padonthebacksideoftheLTC4059/LTC4059Apackageis
soldered to the PC board ground. Correctly soldered to a
where PD is the power dissipated, VCC is the input supply
voltage, VBAT is the battery voltage and IBAT is the charge
current. It is not necessary to perform any worst-case
power dissipation scenarios because the LTC4059
/
2500mm2 double sided 1oz copper board the LTC4059
/
LTC4059A will automatically reduce the charge current to
maintain the die temperature at approximately 115°C.
However, the approximate ambient temperature at which
the thermal feedback begins to protect the IC is:
LTC4059A have a thermal resistance of approximately
60°C/W. Failure to make thermal contact between the
exposed pad on the backside of the package and the
copper board will result in thermal resistances far greater
than60°C/W.Asanexample,acorrectlysolderedLTC4059
/
TA = 115°C – PDθJA
LTC4059A can deliver over 900mA to a battery from a 5V
supply at room temperature. Without a backside thermal
connection, this number could drop to less than 500mA.
TA = 115°C – (VCC – VBAT) • IBAT • θJA
Example: Consider an LTC4059 operating from a 5V wall
adapter providing 900mA to a 3.7V Li-Ion battery. The
ambienttemperatureabovewhichtheLTC4059/LTC4059A
begintoreducethe900mAchargecurrentisapproximately:
Stability Considerations
TheLTC4059containstwocontrolloops:constantvoltage
and constant current. The constant-voltage loop is stable
without any compensation when a battery is connected
with low impedance leads. Excessive lead length, how-
ever, may add enough series inductance to require a
bypasscapacitorofatleast1µFfromBATtoGND. Further-
more, a 4.7µF capacitor with a 0.2Ω to 1Ω series resistor
from BAT to GND is required to keep ripple voltage low
when the battery is disconnected.
TA = 115°C – (5V – 3.7V) • (900mA) • 50°C/W
TA = 115°C – 1.17W • 50°C/W = 115°C – 59°C
TA = 56°C
The LTC4059 can be used above 56°C, but the charge
current will be reduced from 900mA. The approximate
current at a given ambient temperature can be calculated:
115°C – TA
High value capacitors with very low ESR (especially ce-
ramic) reduce the constant-voltage loop phase margin.
Ceramiccapacitorsupto22µFmaybeusedinparallelwith
a battery, but larger ceramics should be decoupled with
0.2Ω to 1Ω of series resistance.
IBAT
=
V – V
• θ
JA
(
)
CC
BAT
Using the previous example with an ambient temperature
of65°C,thechargecurrentwillbereducedtoapproximately:
115°C – 65°C
50°C
I
nconstant-currentmode,thePROGpinisinthefeedback
IBAT
=
=
loop, not the battery. Because of the additional pole
created by PROG pin capacitance, capacitance on this pin
must be kept to a minimum. With no additional capaci-
tanceonthePROGpin, thechargerisstablewithprogram
resistor values as high as 12k. However, additional ca-
pacitance on this node reduces the maximum allowed
4059fa
5V – 3.7V • 50°C/W 65°C/A
(
)
IBAT = 770mA
Furthermore, the voltage at the PROG pin will change
proportionally with the charge current as discussed in the
Programming Charge Current section.
9
LTC4059/LTC4059A
W U U
U
APPLICATIO S I FOR ATIO
program resistor. The pole frequency at the PROG pin
should be kept above 500kHz. Therefore, if the PROG pin
is loaded with a capacitance, CPROG, the following equa-
tion should be used to calculate the maximum resistance
filter can be used on the PROG pin to measure the average
battery current as shown in Figure 4. A 20k resistor has
been added between the PROG pin and the filter capacitor
to ensure stability.
value for RPROG
:
V
CC Bypass Capacitor
1
Many types of capacitors can be used for input bypassing;
however, caution must be exercised when using multi-
layerceramiccapacitors.Becauseoftheself-resonantand
high Q characteristics of some types of ceramic capaci-
tors, high voltage transients can be generated under some
start-up conditions, such as connecting the charger input
to a live power source. For more information, refer to
Application Note 88.
RPROG
≤
2π • 5 •105 •CPROG
Average, rather than instantaneous, battery current may
beofinteresttotheuser.Forexample,ifaswitchingpower
supply operating in low current mode is connected in
parallel with the battery, the average current being pulled
out of the BAT pin is typically of more interest than the
instantaneous current pulses. In such a case, a simple RC
LTC4059
20k
CHARGE CURRENT
PROG
MONTIOR CIRCUITRY
GND
R
PROG
C
FILTER
4059 F04
Figure 4. Isolating Capacitive Load on PROG Pin and Filtering
Figure 5. Photo of Typical Circuit (2.5mm × 2.7mm)
4059fa
10
LTC4059/LTC4059A
U
PACKAGE DESCRIPTIO
DC Package
6-Lead Plastic DFN (2mm × 2mm)
(Reference LTC DWG # 05-08-1703)
R = 0.115
0.38 ± 0.05
TYP
4
6
0.56 ± 0.05
(2 SIDES)
0.675 ±0.05
2.50 ±0.05
0.61 ±0.05
1.15 ±0.05
2.00 ±0.10
(4 SIDES)
(2 SIDES)
PIN 1
NOTCH
PACKAGE
OUTLINE
PIN 1
TOP MARK
(SEE NOTE 5)
(DC6) DFN 0403
3
1
0.25 ± 0.05
0.25 ± 0.05
0.50 BSC
0.50 BSC
0.75 ±0.05
0.200 REF
1.37 ±0.05
(2 SIDES)
1.42 ±0.05
(2 SIDES)
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
NOTE:
1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WCCD-2)
2. ALL DIMENSIONS ARE IN MILLIMETERS
3. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
4. EXPOSED PAD SHALL BE SOLDER PLATED
5. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE
TOP AND BOTTOM OF PACKAGE
4059fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
11
LTC4059/LTC4059A
U
TYPICAL APPLICATIO
V
IN
4.5V TO 6.5V
600mA
2k
V
BAT
LTC4059
EN PROG
Li CC GND
CC
4.2V
Li-Ion
+
1µF
BATTERY
4059 TA03
RELATED PARTS
PART NUMBER
DESCRIPTION
COMMENTS
LTC1733
Monolithic Lithium-Ion Linear Battery Charger
Lithium-Ion Linear Battery Charger in ThinSOTTM
Lithium-Ion Low Battery Detector
Standalone Charger with Programmable Timer, Up to 1.5A Charge Current
Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed
1% Accurate 2.5µA Quiescent Current, SOT-23
LTC1734
LTC1998
LTC4050
Lithium-Ion Linear Battery Charger Controller
Simple Charger uses External FET, Features Preset Voltages, C/10
Charger Detection and Programmable Timer, Input Power Good Indication,
Thermistor Interface
LTC4052
LTC4053
LTC4054
Monolithic Lithium-Ion Battery Pulse Charger
No Blocking Diode or External Power FET Required
USB Compatible Monolithic Li-Ion Battery Charger
Standalone Charger with Programmable Timer, Up to 1.25A Charge Current
Standalone Linear Li-Ion Battery Charger
with Integrated Pass Transistor in ThinSOT
Thermal Regulation Prevents Overheating, C/10 Termination,
C/10 Indicator
LTC4056
LTC4057
LTC4410
Standalone Lithium-Ion Linear Battery Charger
in ThinSOT
Standalone Charger with Programmable Timer, No Blocking Diode,
No Sense Resistor Needed
Monolithic Lithium-Ion Linear Battery Charger
with Thermal Regulation in ThinSOT
No External MOSFET, Sense Resistor or Blocking Diode Required,
Charge Current Monitor for Gas Gauging
USB Power Manager
For Simultaneous Operation of USB Peripheral and Battery Charging from USB
Port, Keeps Current Drawn from USB Port Constant, Keeps Battery Fresh, Use
with the LTC4053, LTC1733 or LTC4054
LTC4058
950mA Standalone Li-Ion Charger in 3mm × 3mm
DFN
USB Compatible, Thermal Regulation Protects Against Overheating
ThinSOT is a trademark of Linear Technology Corporation.
4059fa
LT/TP 0304 1K REV A • PRINTED IN USA
12 LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
●
●
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
LINEAR TECHNOLOGY CORPORATION 2003
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