FEATURES
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LTC4085
USB Power Manager with
Ideal Diode Controller and
Li-Ion Charger
DESCRIPTION
The LTC
®
4085 is a USB power manager and Li-Ion battery
charger designed for portable battery-powered applica-
tions. The part controls the total current used by the USB
peripheral for operation and battery charging. The total
input current can be limited to 20% or 100% of a pro-
grammed value up to 1.5A (typically 100mA or 500mA).
Battery charge current is automatically reduced such that
the sum of the load current and charge current does not
exceed the programmed input current limit.
The LTC4085 includes a complete constant-current/
constant-voltage linear charger for single cell Li-ion bat-
teries. The float voltage applied to the battery is held to a
tight 0.8% tolerance, and charge current is programmable
using an external resistor to ground. An end-of-charge
status output
CHRG
indicates full charge. Total charge
time is programmable by an external capacitor to ground.
When the battery drops 100mV below the float voltage,
automatic recharging of the battery occurs. Also featured
is an NTC thermistor input used to monitor battery tem-
perature while charging.
The LTC4085 is available in a 14-lead low profile 4mm
×
3mm DFN package.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
PowerPath is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners. Protected by U.S. Patents, including 6522118,6700364.
Other patents pending.
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Seamless Transition Between Input Power Sources:
Li-Ion Battery, USB and 5V Wall Adapter
215mΩ Internal Ideal Diode Plus Optional External
Ideal Diode Controller Provide Low Loss PowerPath™
When Wall Adapter/USB Input Not Present
Load Dependent Charging Guarantees Accurate USB
Input Current Compliance
Constant-Current/Constant-Voltage Operation with
Thermal Feedback to Maximize Charging Rate Without
Risk of Overheating*
Selectable 100% or 20% Input Current Limit
(e.g., 500mA/100mA)
Battery Charge Current Independently Programmable
Up to 1.2A
Preset 4.2V Charge Voltage with 0.8% Accuracy
C/10 Charge Current Detection Output
NTC Thermistor Input for Temperature Qualified Charging
Tiny (4mm
×
3mm
×
0.75mm) 14-Lead DFN Package
APPLICATIONS
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Portable USB Devices: Cameras, MP3 Players, PDAs
TYPICAL APPLICATION
5V WALL
ADAPTER
INPUT
5V (NOM)
FROM USB
CABLE V
BUS
I
IN
I
LOAD
TO LDOs,
REGs, ETC
4.7μF
IN
4.7μF SUSPEND USB POWER
100mA 500mA SELECT
SUSP
HPWR
PROG
CLPROG
NTC
V
NTC
10k
GND
LTC4085
WALL
ACPR
OUT
GATE
BAT
CHRG
TIMER
I
BAT
Input and Battery Current vs Load Current
R
PROG
= 100k, R
CLPROG
= 2k
600
500
I
IN
1k
510Ω
400
CURRENT (mA)
I
LOAD
300
200
100
0
–100
WALL = 0V
0
100
200
I
BAT
(DISCHARGING)
400
300
I
LOAD
(mA)
500
600
I
BAT
(CHARGING)
*
+
0.1μF
*
OPTIONAL - TO LOWER
IDEAL DIODE IMPEDANCE
4085 TA01
100k
2k
10k
4085 TA01b
4085fd
1
LTC4085
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2, 3, 4, 5)
PIN CONFIGURATION
TOP VIEW
IN
OUT
CLPROG
HPWR
SUSP
TIMER
WALL
1
2
3
4
5
6
7
15
14 BAT
13 GATE
12 PROG
11
CHRG
10
ACPR
9 V
NTC
8 NTC
Terminal Voltage
IN, OUT
t < 1ms and Duty Cycle < 1% ................... –0.3V to 7V
Steady State ............................................ –0.3V to 6V
BAT,
CHRG,
HPWR, SUSP, WALL,
ACPR
..... –0.3V to 6V
NTC, TIMER, PROG, CLPROG .......–0.3V to (V
CC
+ 0.3V)
Pin Current (Steady State)
IN, OUT, BAT (Note 6) ..............................................2.5A
Operating Temperature Range .................–40°C to 85°C
Maximum Operating Junction Temperature ...........110°C
Storage Temperature Range .................. –65°C to 125°C
DE PACKAGE
14-LEAD (4mm 3mm) PLASTIC DFN
T
JMAX
= 125°C,
θ
JA
= 40°C/W
EXPOSED PAD (PIN 15) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC4085EDE#PBF
TAPE AND REEL
LTC4085EDE#TRPBF
PART MARKING
4085
PACKAGE DESCRIPTION
14-Lead (4mm
×
3mm) Plastic DFN
TEMPERATURE RANGE
–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/
The
l
indicates specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 5V, V
BAT
= 3.7V, HPWR = 5V, WALL = 0V, R
PROG
= 100k,
R
CLPROG
= 2k, unless otherwise noted.
SYMBOL
V
IN
V
BAT
I
IN
PARAMETER
Input Supply Voltage
Input Voltage
Input Supply Current
CONDITIONS
IN and OUT
BAT
I
BAT
= 0 (Note 7)
Suspend Mode; SUSP = 5V
Suspend Mode; SUSP = 5V, WALL = 5V,
V
OUT
= 4.8V
V
OUT
= 5V, V
IN
= 0V, NTC = V
NTC
V
BAT
= 4.3V, Charging Stopped
Suspend Mode; SUSP = 5V
V
IN
= 0V, BAT Powers OUT, No Load
V
IN
Powers Part, Rising Threshold
V
OUT
Powers Part, Rising Threshold
V
IN
Rising – V
IN
Falling
or V
OUT
Rising – V
OUT
Falling
R
CLPROG
= 2k (0.1%), HPWR = 5V
R
CLPROG
= 2k (0.1%), HPWR = 0V
(Note 8)
I
OUT
= 100mA Load
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ELECTRICAL CHARACTERISTICS
MIN
4.35
TYP
MAX
5.5
4.3
UNITS
V
V
mA
μA
μA
mA
μA
μA
μA
V
V
mV
0.5
50
60
0.7
15
22
60
3.6
2.75
3.8
2.95
130
1.2
100
110
1.4
27
35
100
4
3.15
I
OUT
I
BAT
Output Supply Current
Battery Drain Current
V
UVLO
∆V
UVLO
Current Limit
I
LIM
I
IN(MAX)
R
ON
Input or Output Undervoltage Lockout
Input or Output Undervoltage Lockout
Current Limit
Maximum Input Current Limit
ON Resistance V
IN
to V
OUT
475
90
500
100
2.4
215
525
110
mA
mA
A
mΩ
4085fd
2
LTC4085
The
l
indicates specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 5V, V
BAT
= 3.7V, HPWR = 5V, WALL = 0V, R
PROG
= 100k,
R
CLPROG
= 2k, unless otherwise noted.
SYMBOL
V
CLPROG
I
SS
V
CLEN
Battery Charger
V
FLOAT
I
BAT
I
BAT(MAX)
V
PROG
k
EOC
I
TRIKL
V
TRIKL
V
CEN
V
RECHRG
t
TIMER
Regulated Output Voltage
Current Mode Charge Current
Maximum Charge Current
PROG Pin Voltage
Ratio of End-of-Charge Current to
Charge Current
Trickle Charge Current
Trickle Charge Threshold Voltage
Charger Enable Threshold Voltage
Recharge Battery Threshold Voltage
TIMER Accuracy
Recharge Time
Low-Battery Trickle Charge Time
T
LIM
Internal Ideal Diode
R
FWD
R
DIO(ON)
V
FWD
Incremental Resistance, V
ON
Regulation
ON Resistance V
BAT
to V
OUT
Voltage Forward Drop (V
BAT
– V
OUT
)
I
BAT
= 100mA
I
BAT
= 600mA
I
BAT
= 5mA
I
BAT
= 100mA
I
BAT
= 600mA
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ELECTRICAL CHARACTERISTICS
PARAMETER
CLPROG Pin Voltage
Soft-Start Inrush Current
Input Current Limit Enable Threshold
Voltage
CONDITIONS
R
PROG
= 2k
R
PROG
= 1k
IN or OUT
(V
IN
– V
OUT
) V
IN
Rising
(V
IN
– V
OUT
) V
IN
Falling
I
BAT
= 2mA
I
BAT
= 2mA, (0°C to 85°C)
R
PROG
= 100k (0.1%), No Load
R
PROG
= 50k (0.1%), No Load
(Note 8)
R
PROG
= 100k
R
PROG
= 50k
V
BAT
= V
FLOAT
(4.2V)
V
BAT
= 2V, R
PROG
= 100k (0.1%)
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MIN
0.98
0.98
20
–80
4.165
4.158
465
900
0.98
0.98
0.085
40
2.8
TYP
1
1
5
50
–60
4.2
4.2
500
1000
1.5
1
1
0.1
50
2.9
55
80
MAX
1.02
1.02
80
–20
4.235
4.242
535
1080
1.02
1.02
0.11
60
3
UNITS
V
V
mA/μs
mV
mV
V
V
mA
mA
A
V
V
mA/mA
mA
V
mV
mV
(V
OUT
– V
BAT
) Falling; V
BAT
= 4V
(V
OUT
– V
BAT
) Rising; V
BAT
= 4V
V
FLOAT
– V
RECHRG
V
BAT
= 4.3V
Percent of Total Charge Time
Percent of Total Charge Time, V
BAT
< 2.8V
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65
-10
100
50
25
105
135
10
mV
%
%
%
°C
Junction Temperature in Constant
Temperature Mode
125
215
10
30
55
160
2.8
550
2.2
50
mΩ
mΩ
mV
mV
mV
V
mA
A
mV
0.25
0.4
V
V
V
μA
V
OFF
I
FWD
I
D(MAX)
External Ideal Diode
V
FWD,EDA
Logic
V
OL
V
IH
V
IL
I
PULLDN
Diode Disable Battery Voltage
Load Current Limit, for V
ON
Regulation
Diode Current Limit
External Ideal Diode Forward Voltage
Output Low Voltage,
CHRG, ACPR
Input High Voltage
Input Low Voltage
Logic Input Pull-Down Current
V
GATE
= 1.85V; I
GATE
= 0
I
SINK
= 5mA
SUSP HPWR Pin
,
SUSP HPWR Pin
,
SUSP HPWR
,
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20
0.1
1.2
2
4085fd
3
LTC4085
The
l
indicates specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 5V, V
BAT
= 3.7V, HPWR = 5V, WALL = 0V, R
PROG
= 100k,
R
CLPROG
= 2k, unless otherwise noted.
SYMBOL
V
CHG(SD)
I
CHG(SD)
V
WAR
V
WAF
V
WDR
V
WDF
I
WALL
NTC
V
VNTC
I
NTC
V
COLD
V
HOT
V
DIS
V
NTC
Bias Voltage
NTC Input Leakage Current
Cold Temperature Fault Threshold
Voltage
Hot Temperature Fault Threshold
Voltage
NTC Disable Voltage
I
VNTC
= 500μA
V
NTC
= 1V
Rising Threshold
Hysteresis
Falling Threshold
Hysteresis
NTC Input Voltage to GND (Falling)
Hysteresis
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ELECTRICAL CHARACTERISTICS
PARAMETER
Charger Shutdown Threshold Voltage
on TIMER
Charger Shutdown Pull-Up Current
on TIMER
Absolute Wall Input Threshold Voltage
Absolute Wall Input Threshold Voltage
Delta Wall Input Threshold Voltage
Delta Wall Input Threshold Voltage
Wall Input Current
CONDITIONS
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MIN
0.15
5
4.15
TYP
MAX
0.4
UNITS
V
μA
V
TIMER
= 0V
V
WALL
Rising Threshold
V
WALL
Falling Threshold
V
WALL
– V
BAT
Rising Threshold
V
WALL
– V
BAT
Falling Threshold
V
WALL
= 5V
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14
4.25
3.12
75
4.35
V
V
mV
l
0
25
75
50
150
mV
μA
V
4.4
4.85
0
0.74 • V
VNTC
0.02 • V
VNTC
0.29 • V
VNTC
0.01 • V
VNTC
±1
μA
V
V
V
V
75
100
35
125
mV
mV
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:
V
CC
is the greater of V
IN
, V
OUT
or V
BAT
.
Note 3:
All voltage values are with respect to GND.
Note 4:
This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperatures will exceed 125°C when overtemperature protection is
active. Continuous operation above the specified maximum operating
junction temperature may result in device degradation or failure.
Note 5:
The LTC4085E is guaranteed to meet specified performance 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 6:
Guaranteed by long term current density limitations.
Note 7:
Total input current is equal to this specification plus 1.002 • I
BAT
where I
BAT
is the charge current.
Note 8:
Accuracy of programmed current may degrade for currents greater
than 1.5A.
4085fd
4
LTC4085
TYPICAL PERFORMANCE CHARACTERISTICS
Input Supply Current
vs Temperature
900
800
700
600
I
IN
(μA)
500
400
300
200
100
0
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
4085 G01
T
A
= 25°C unless otherwise noted.
Battery Drain Current vs Temperature
(BAT Powers OUT, No Load)
100
V
IN
= 0V
90
V
BAT
= 4.2V
80
70
I
BAT
(μA)
60
50
40
30
20
Input Supply Current vs
Temperature (Suspend Mode)
70
V
IN
= 5V
V
BAT
= 4.2V
60
R
PROG
= 100k
R
CLPROG
= 2k
50
SUSP = 5V
I
IN
(μA)
40
30
20
10
0
–50
V
IN
= 5V
V
BAT
= 4.2V
R
PROG
= 100k
R
CLPROG
= 2k
10
25
50
25
0
TEMPERATURE (°C)
75
100
4085 G02
0
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
4085 G03
Input Current Limit
vs Temperature, HPWR = 5V
525
V
IN
= 5V
V
BAT
= 3.7V
R
PROG
= 100k
515
R
CLPROG
= 2k
505
110
Input Current Limit
vs Temperature, HPWR = 0V
V
IN
= 5V
108
V
BAT
= 3.7V
R
PROG
= 100k
106
R
CLPROG
= 2k
104
I
IN
(mA)
102
100
98
96
V
CLPROG
(V)
1.2
1.0
0.8
0.6
0.4
0.2
CLPROG Pin Voltage
vs Temperature
V
IN
= 5V
R
CLPROG
= 2k
HPWR = 5V
I
IN
(mA)
495
485
94
92
HPWR = 0V
475
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
4085 G04
90
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
4085 G05
0
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
4085 G06
PROG Pin Voltage
vs Temperature
V
IN
= 5V
V
BAT
= 4.2V
1.015
R
PROG
= 100k
R
CLPROG
= 2k
1.010
V
FLOAT
(V)
V
PROG
(V)
1.005
1.000
0.995
0.990
0.985
0.980
–50
–25
50
25
TEMPERATURE (°C)
0
75
100
4085 G07
V
FLOAT
Load Regulation
4.30
4.25
4.20
4.15
4.10
4.190
4.05
4.00
0
200
400
600
I
BAT
(mA)
800
1000
4085 G08
Battery Regulation (Float)
Voltage vs Temperature
4.220
4.215
4.210
V
FLOAT
(V)
4.205
4.200
4.195
V
IN
= 5V
I
BAT
= 2mA
1.020
R
PROG
= 34k
4.185
4.180
–50
–25
0
50
25
TEMPERATURE (°C)
75
100
4085 G09
4085fd
5
Embedded System
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