FEATURES
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LTC4088-1/LTC4088-2
High Efficiency Battery
Charger/USB Power Manager
with Regulated Output Voltage
DESCRIPTIO
The LTC
®
4088-1/LTC4088-2 is a high efficiency USB
PowerPath
TM
controller and Li-Ion/Polymer battery
charger. It includes a synchronous switching input regu-
lator, a full-featured battery charger and an ideal diode.
Designed specifically for USB applications, the
LTC4088-1/LTC4088-2’s switching regulator auto-
matically limits its input current to either 100mA, 500mA
or 1A via logic control. The LTC4088-1 powers-up with the
charger off; the LTC4088-2 powers-up with the charger on.
The switching input stage provides power to V
OUT
where
power sharing between the application circuit and the
battery charger is managed. Charge current is automati-
cally reduced to maintain a regulated 3.6V V
OUT
during
low-battery conditions. As the battery is charged, V
OUT
tracks V
BAT
for high efficiency charging. This feature al-
lows the LTC4088-1/LTC4088-2 to provide more power to
the application and eases thermal issues in constrained
applications.
An ideal diode ensures that system power is available
from the battery when the input current limit is reached
or if the USB or wall supply is removed.
The LTC4088-1/LTC4088-2 is available in the low profile
14-Lead 4mm
×
3mm
×
0.75mm DFN surface mount
package.
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Switching Regulator Makes Optimal Use of Limited
Power Available from USB Port to Charge Battery
and Power Application
180mΩ Internal Ideal Diode Plus External Ideal Diode
Controller Seamlessly Provide Low Loss Power Path
When Input Power is Limited or Unavailable
Automatic Charge Current Reduction Maintains
3.6V Minimum V
OUT
Full Featured Li-Ion/Polymer Battery Charger
V
BUS
Operating Range: 4.25V to 5.5V (7V Absolute
Maximum—Transient)
1.2A Maximum Input Current Limit
1.5A Maximum Charge Current with Thermal Limiting
Bat-Track
TM
Adaptive Output Control
Slew Control Reduces Switching EMI
Low Profile (0.75mm) 14-Lead 4mm
×
3mm DFN Package
APPLICATIO S
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Media Players
Digital Cameras
GPS
PDAs
Smart Phones
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
PowerPath and Bat-Track are trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 6522118
TYPICAL APPLICATIO
WALL
USB
10µF
High Efficiency Battery Charger/USB Power Manager
3.3µH
SYSTEM
LOAD
Switching Regulator Efficiency to
System Load (P
OUT
/P
BUS
)
100
90
80
V
BUS
SW V
OUT
D0
V
OUTS
D1
GATE
LTC4088-1/LTC4088-2
D2
CHRG
BAT
CLPROG
PROG C/X GND NTC
8.2Ω
0.1µF
Li-Ion
EFFICIENCY (%)
70
60
50
40
30
20
10
10µF
+
408812 TA01a
2.94k
499Ω
0
0.01
U
U
U
BAT = 4.2V
BAT = 3.3V
V
BUS
= 5V
I
BAT
= 0mA
10x MODE
0.1
I
OUT
(A)
1
408812 TA01b
40881fb
1
LTC4088-1/LTC4088-2
ABSOLUTE
(Note 1)
AXI U RATI GS
V
BUS
(Transient) t < 1ms, Duty Cycle < 1% .. –0.3V to 7V
V
BUS
(Static), BAT,
CHRG,
NTC, D0,
D1, D2.......................................................... –0.3V to 6V
I
CLPROG
....................................................................3mA
I
PROG
, I
C/X
................................................................2mA
I
CHRG
......................................................................75mA
I
OUT
.............................................................................2A
I
SW
..............................................................................2A
I
BAT
.............................................................................2A
Maximum Operating Junction Temperature .......... 125°C
Operating Temperature Range.................. –40°C to 85°C
Storage Temperature Range................... –65°C to 125°C
ORDER INFORMATION
LEAD FREE FINISH
LTC4088EDE-1#PBF
LTC4088EDE-2#PBF
TAPE AND REEL
LTC4088EDE-1#TRPBF
LTC4088EDE-2#TRPBF
PART MARKING
40881
40882
PACKAGE DESCRIPTION
14-Lead (4mm
×
3mm
×
0.75mm) Plastic DFN
14-Lead (4mm
×
3mm) Plastic DFN
TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
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/
ELECTRICAL CHARACTERISTICS
SYMBOL
V
BUS
I
BUS(LIM)
PARAMETER
Input Supply Voltage
Total Input Current
Input Power Supply
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BUS
= 5V, BAT = 3.8V, R
CLPROG
= 2.94k, unless otherwise noted.
CONDITIONS
l
I
BUSQ
(Note 4)
Input Quiescent Current
h
CLPROG
(Note 4) Ratio of Measured V
BUS
Current to
CLPROG Program Current
2
U
W W
W
PIN CONFIGURATION
TOP VIEW
NTC
CLPROG
V
OUTS
D2
C/X
PROG
CHRG
1
2
3
4
5
6
7
15
14 D1
13 D0
12 SW
11 VBUS
10 V
OUT
9 BAT
8 GATE
DE PACKAGE
14-LEAD (4mm
×
3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 37°C/W
EXPOSED PAD (PIN 15) IS GND, MUST BE SOLDERED TO PCB
MIN
4.35
92
445
815
0.32
1.6
TYP
MAX
5.5
UNITS
V
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA/mA
mA/mA
mA/mA
mA/mA
mA/mA
40881fb
1x Mode
5x Mode
10x Mode
Low Power Suspend Mode
High Power Suspend Mode
1x Mode
5x Mode
10x Mode
Low Power Suspend Mode
High Power Suspend Mode
1x Mode
5x Mode
10x Mode
Low Power Suspend Mode
High Power Suspend Mode
l
l
l
l
l
97
470
877
0.39
2.05
6
14
14
0.038
0.038
224
1133
2140
11.3
59.4
100
500
1000
0.5
2.5
LTC4088-1/LTC4088-2
ELECTRICAL CHARACTERISTICS
SYMBOL
I
OUT
PARAMETER
V
OUT
Current Available Before
Discharging Battery
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BUS
= 5V, BAT = 3.8V, R
CLPROG
= 2.94k, unless otherwise noted.
CONDITIONS
1x Mode, BAT = 3.3V
5x Mode, BAT = 3.3V
10x Mode, BAT = 3.3V
Low Power Suspend Mode
High Power Suspend Mode
1x, 5x, 10x Modes
Suspend Modes
Rising Threshold
Falling Threshold
Rising Threshold
Falling Threshold
1x, 5x, 10x Modes, 0V < BAT ≤ 4.2V,
I
OUT
= 0mA, Battery Charger Off
USB Suspend Modes, I
OUT
= 250µA
3.5
4.5
1.8
3.95
MIN
TYP
135
672
1251
0.32
2.04
1.188
100
4.30
4.00
200
50
BAT + 0.3
4.6
2.25
0.18
0.30
1x, 5x Modes
10x Mode
2
3
15
4.179
4.165
980
196
4.200
4.200
1030
206
3.5
4.221
4.235
1080
220
5
4.7
4.7
2.7
4.35
MAX
UNITS
mA
mA
mA
mA
mA
V
mV
V
V
mV
mV
V
V
MHz
Ω
Ω
A
A
Ω
V
V
mA
mA
µA
0.26
1.6
0.41
2.46
V
CLPROG
V
UVLO
V
DUVLO
V
OUT
CLPROG Servo Voltage in Current Limit
V
BUS
Undervoltage Lockout
V
BUS
to BAT Differential Undervoltage
Lockout
V
OUT
Voltage
f
OSC
R
PMOS
R
NMOS
I
PEAK
R
SUSP
Battery Charger
V
FLOAT
I
CHG
I
BAT
Switching Frequency
PMOS On Resistance
NMOS On Resistance
Peak Inductor Current Clamp
Suspend LDO Output Resistance
BAT Regulated Output Voltage
0°C ≤ T
A
≤ 85°C
Constant-Current Mode Charge Current
Battery Drain Current
R
PROG
= 1k
R
PROG
= 5k
V
BUS
> V
UVLO
, PowerPath Switching
Regulator On, Battery Charger Off,
I
OUT
= 0µA
V
BUS
= 0V, I
OUT
= 0µA (Ideal Diode Mode)
23
1.000
0.100
1031
35
µA
V
V
mA/mA
V
PROG
V
PROG,TRKL
h
PROG
V
TRKL
∆V
TRKL
V
RECHRG
t
TERM
t
BADBAT
I
C/X
V
C/X
h
C/X
V
CHRG
I
CHRG
PROG Pin Servo Voltage
PROG Pin Servo Voltage in Trickle
Charge
Ratio of I
BAT
to PROG Pin Current
Trickle Charge Threshold Voltage
Trickle Charge Hysteresis Voltage
Recharge Battery Threshold Voltage
Safety Timer Termination Period
Bad Battery Termination Time
Battery Charge Current at Programmed
End of Charge Indication
C/X Threshold Voltage
Battery Charge Current Ratio to C/X
CHRG
Pin Output Low Voltage
CHRG
Pin Input Current
I
CHRG
= 5mA
BAT = 4.5V, V
CHRG
= 5V
Threshold Voltage Relative to V
FLOAT
Timer Starts when V
BAT
= V
FLOAT
BAT < V
TRKL
R
C/X
= 1k
R
C/X
= 5k
–80
3.2
0.4
85
BAT Rising
2.7
BAT < V
TRKL
2.85
135
–100
4.0
0.5
100
20
100
1031
65
0
3.0
–120
4.8
0.6
115
V
mV
mV
Hour
Hour
mA
mA
mV
mA/mA
100
1
mV
µA
40881fb
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LTC4088-1/LTC4088-2
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
BUS
= 5V, BAT = 3.8V, R
CLPROG
= 2.94k, unless otherwise noted.
SYMBOL
R
ON_CHG
T
LIM
NTC
V
COLD
V
HOT
V
DIS
I
NTC
Ideal Diode
V
FWD
R
DROPOUT
I
MAX
V
IL
V
IH
I
PD
Forward Voltage Detection
Internal Diode On-Resistance, Dropout
Diode Current Limit
Input Low Voltage
Input High Voltage
Static Pull-Down Current
V
PIN
= 1V
1.2
2
I
OUT
= 10mA
V
BUS
= 0V, I
OUT
= 10mA
I
OUT
= 200mA
2
0.4
15
2
0.18
mV
mV
Ω
A
V
V
µA
Cold Temperature Fault Threshold
Voltage
Hot Temperature Fault Threshold
Voltage
NTC Disable Threshold Voltage
NTC Leakage Current
Rising Threshold
Hysteresis
Falling Threshold
Hysteresis
Falling Threshold
Hysteresis
V
NTC
= V
BUS
= 5V
75.0
33.4
0.7
–50
76.5
1.5
34.9
1.5
1.7
50
78.0
36.4
2.7
50
%V
BUS
%V
BUS
%V
BUS
%V
BUS
%V
BUS
mV
nA
PARAMETER
Battery Charger Power FET
On-Resistance (Between V
OUT
and BAT)
Junction Temperature in Constant
Temperature Mode
CONDITIONS
I
BAT
= 200mA
MIN
TYP
0.18
110
MAX
UNITS
Ω
°C
ELECTRICAL CHARACTERISTICS
Logic (D0, D1, D2)
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:
The LTC4088E-1/ LTC4088E-2 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.
Note 3:
The LTC4088E-1/
LTC4088E-2
includes overtemperature protection
that is intended to protect the device during momentary overload
conditions. Junction temperature will exceed 125°C when overtemperature
protection is active. Continuous operation above the specified maximum
operating junction temperature may impair device reliability.
Note 4:
Total input current is the sum of quiescent current, I
BUSQ
, and
measured current given by V
CLPROG
/R
CLPROG
• (h
CLPROG
+ 1).
40881fb
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LTC4088-1/LTC4088-2
TYPICAL PERFOR A CE CHARACTERISTICS
T
A
= 25°C unless otherwise noted.
Ideal Diode V-I Characteristics
1.0
INTERNAL IDEAL DIODE
WITH SUPPLEMENTAL
EXTERNAL VISHAY
Si2333 PMOS
RESISTANCE (Ω)
0.25
0.8
CURRENT (A)
0.6
INTERNAL IDEAL
DIODE ONLY
0.4
INTERNAL IDEAL
DIODE
0.15
OUTPUT VOLTAGE (V)
0.2
V
BUS
= 0V
V
BUS
= 5V
0
0
0.04
0.12
0.16
0.08
FORWARD VOLTAGE (V)
0.20
408812 G01
USB Limited Battery Charge
Current vs Battery Voltage
700
600
CHARGE CURRENT (mA)
CHARGE CURRENT (mA)
500
400
300
200
100
V
BUS
= 5V
R
PROG
= 1k
R
CLPROG
= 2.94k
150
125
100
75
50
25
5x USB SETTING,
BATTERY CHARGER SET FOR 1A
3.0
3.3
3.6
3.9
4.2
BATTERY VOLTAGE (V)
408812 G04
V
BUS
= 5V
R
PROG
= 1k
R
CLPROG
= 2.94k
BATTERY CURRENT (µA)
0
2.7
PowerPath Switching Regulator
Efficiency vs Output Current
100
90
EFFICIENCY (%)
80
70
60
50
40
0.01
V
BAT
= 3.8V
1x MODE
90
5x, 10x MODE
88
EFFICIENCY (%)
V
BUS
CURRENT (µA)
0.1
OUTPUT CURRENT (A)
U W
1
408812 G07
Ideal Diode Resistance
vs Battery Voltage
4.50
Output Voltage vs Output Current
(Battery Charger Disabled)
V
BAT
= 4V
V
BUS
= 5V
5x MODE
0.20
4.25
4.00
V
BAT
= 3.4V
3.75
0.10
INTERNAL IDEAL DIODE
WITH SUPPLEMENTAL
EXTERNAL VISHAY
Si2333 PMOS
0.05
3.50
0
2.7
3.25
3.0
3.6
3.9
3.3
BATTERY VOLTAGE (V)
4.2
408812 G02
0
200
600
800
400
OUTPUT CURRENT (mA)
1000
408812 G03
USB Limited Battery Charge
Current vs Battery Voltage
25
Battery Drain Current
vs Battery Voltage
I
OUT
= 0µA
V
BUS
= 0V
20
15
10
V
BUS
= 5V
(SUSPEND MODE)
5
1x USB SETTING,
BATTERY CHARGER SET FOR 1A
2.7
3.0
3.3
3.6
3.9
BATTERY VOLTAGE (V)
4.2
408812 G05
0
0
2.7
3.0
3.6
3.9
3.3
BATTERY VOLTAGE (V)
4.2
408812 G06
Battery Charging Efficiency vs
Battery Voltage with No External
Load (P
BAT
/P
BUS
)
R
CLPROG
= 2.94k
R
PROG
= 1k
I
OUT
= 0mA
5x CHARGING
EFFICIENCY
86
1x CHARGING
EFFICIENCY
50
V
BUS
Current vs V
BUS
Voltage
(Suspend)
I
OUT
= 0mA
40
30
84
20
82
10
80
2.7
3.0
3.6
3.9
3.3
BATTERY VOLTAGE (V)
0
4.2
408812 G08
1
2
4
3
V
BUS
VOLTAGE (V)
5
6
408812 G09
40881fb
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