FEATURES
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LTC4085-3
USB Power Manager with
Ideal Diode Controller and
3.95V Li-Ion Charger
DESCRIPTION
The LTC
®
4085-3 is a USB power manager and Li-Ion/Poly-
mer battery charger designed for portable battery-powered
applications. 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 programmed 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 LTC4085-3 includes a complete constant-current/
constant-voltage linear charger for single cell Li-Ion bat-
teries. This 3.95V version of the standard LTC4085 is
intended for applications which have extended battery
lifetime requirements or those that require high temperature
(approximately >60°C) operation or storage. Under these
conditions, a reduced float voltage will trade-off initial cell
capacity for the benefit of increased capacity retention
over the life of the battery. A reduced float voltage also
minimizes swelling in prismatic and polymer cells, and
avoids open CID (pressure fuse) in cylindrical cells.
The LTC4085-3 also includes a programmable termina-
tion timer, automatic recharging, an end-of-charge status
output and an NTC thermistor.
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Seamless Transition Between Input Power Sources:
Li-Ion/Polymer 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
3.95V Float Voltage Improves Battery Life Span and
High Temperature Safety Margin
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 3.95V Charge Voltage with ±0.8% Accuracy
C/10 Charge Current Detection Output
Tiny (4mm
×
3mm
×
0.75mm) 14-Lead DFN Package
APPLICATIONS
■
Portable USB Devices
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
Bat-Track, PowerPath and ThinSOT are trademarks 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.
TYPICAL APPLICATION
5V WALL
ADAPTER
INPUT
5V (NOM)
FROM USB
CABLE V
BUS
I
IN
I
LOAD
TO LDOs,
REGs, ETC
1k
IN
4.7μF
SUSPEND USB POWER
100mA 500mA SELECT
SUSP
HPWR
PROG
CLPROG
NTC
V
NTC
10k
GND
LTC4085-3
WALL
ACPR
4.7μF
510Ω
Input and Battery Current vs Load Current
R
PROG
= 100k, R
CLPROG
= 2k
600
500
400
CURRENT (mA)
I
LOAD
300
200
100
0
–100
0
WALL = 0V
100
200
I
BAT
(DISCHARGING)
400
300
I
LOAD
(mA)
500
600
I
BAT
(CHARGING)
I
IN
OUT
GATE
BAT
CHRG
TIMER
I
BAT
*
+
0.1μF
*
OPTIONAL - TO LOWER
IDEAL DIODE IMPEDANCE
40853 TA01
100k
2k
10k
40853 TA01b
40853f
1
LTC4085-3
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
= 43°C/W
EXPOSED PAD (PIN 15) IS GND, MUST BE CONNECTED TO PCB
ORDER INFORMATION
LEAD FREE FINISH
LTC4085EDE-3#PBF
TAPE AND REEL
LTC4085EDE-3#TRPBF
PART MARKING
40853
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
●
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
= 4.05V, 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
●
●
●
●
●
●
●
●
●
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
ΔV
UVLO
Input or Output Undervoltage Lockout
Input or Output Undervoltage Lockout
40853f
2
LTC4085-3
The
●
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
Current Limit
I
LIM
I
IN(MAX)
R
ON
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
●
ELECTRICAL CHARACTERISTICS
PARAMETER
Current Limit
Maximum Input Current Limit
ON Resistance V
IN
to V
OUT
CLPROG Pin Voltage
Soft Start Inrush Current
Input Current Limit Enable Threshold
Voltage
CONDITIONS
R
CLPROG
= 2k (0.1%), HPWR = 5V
R
CLPROG
= 2k (0.1%), HPWR = 0V
(Note 8)
I
OUT
= 100mA Load
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 – 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
(3.95V)
V
BAT
= 2V, R
PROG
= 100k (0.1%)
●
●
●
●
●
●
●
●
●
●
MIN
475
90
TYP
500
100
2.4
215
MAX
525
110
UNITS
mA
mA
A
mΩ
0.98
0.98
20
1
1
5
50
–60
3.95
3.95
500
1000
1.5
1
1
0.1
50
2.9
55
80
1.02
1.02
80
V
V
mA/μs
mV
mV
V
V
mA
mA
A
V
V
mA/mA
mA
V
mV
mV
3.915
3.910
465
900
0.98
0.98
0.085
35
2.75
3.985
3.990
535
1080
1.02
1.02
0.11
60
3
(V
OUT
– V
BAT
) Falling; V
BAT
= 4V
(V
OUT
– V
BAT
) Rising; V
BAT
= 4V
V
FLOAT
– V
RECHRG
V
BAT
= 4.05V
Percent of Total Charge Time
Percent of Total Charge Time, V
BAT
< 2.8V
●
60
–10
95
50
25
105
130
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
V
OFF
I
FWD
I
D(MAX)
Diode Disable Battery Voltage
Load Current Limit, for V
ON
Regulation
Diode Current Limit
40853f
3
LTC4085-3
The
●
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
External Ideal Diode
V
FWD,EDA
Logic
V
OL
V
IH
V
IL
I
PULLDN
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
●
●
ELECTRICAL CHARACTERISTICS
PARAMETER
External Ideal Diode Forward Voltage
Output Low Voltage
CHRG, ACPR
Input High Voltage
Input Low Voltage
Logic Input Pull-Down Current
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
V
GATE
= 1.85V; I
GATE
= 0
I
SINK
= 5mA
SUSP HPWR Pin
,
SUSP HPWR Pin
,
SUSP HPWR
,
●
●
●
●
MIN
TYP
20
0.1
MAX
UNITS
mV
0.4
0.4
V
V
V
μA
V
μA
1.2
2
0.14
5
4.15
14
4.25
3.12
75
4.35
0.4
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
●
●
V
V
mV
●
0
25
75
60
150
mV
μA
V
4.4
4.85
0
0.738 • V
VNTC
0.018 • V
VNTC
0.326 • V
VNTC
0.015 • 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 110°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-3 is guaranteed to meet specified performance
from 0° 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.
40853f
4
LTC4085-3
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
10
0
–50
I
IN
(μA)
V
IN
= 5V
V
BAT
= 3.95V
R
PROG
= 100k
R
CLPROG
= 2k
70
T
A
= 25°C unless otherwise noted.
Battery Drain Current
vs Temperature
(BAT Powers OUT, No Load)
100
V
IN
= 0V
90 V
BAT
= 3.95V
80
70
I
BAT
(μA)
60
50
40
30
20
10
Input Supply Current vs
Temperature (Suspend Mode)
V
IN
= 5V
V
BAT
= 3.95V
60 R
PROG
= 100k
R
CLPROG
= 2k
50 SUSP = 5V
40
30
20
25
50
25
0
TEMPERATURE (°C)
75
100
40853 G02
0
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
40853 G01
40853 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
90
–50
–25
25
50
0
TEMPERATURE (°C)
75
100
0
–50
–25
0
25
50
TEMPERATURE (°C)
75
100
40853 G04
40853 G05
40853 G06
PROG Pin Voltage
vs Temperature
V
IN
= 5V
= 3.80V
V
1.015
BAT
R
PROG
= 100k
= 2k
R
1.010
CLPROG
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
40851 G07
V
FLOAT
Load Regulation
4.05
4.00
3.95
3.90
3.85
3.80
3.75
0
200
400
600
I
BAT
(mA)
800
1000
40853 G08
Battery Regulation (Float)
Voltage vs Temperature
3.970
3.965
3.960
V
FLOAT
(V)
3.955
3.950
3.945
3.940
3.935
3.930
–50
–25
50
25
TEMPERATURE (°C)
0
75
100
40853 G09
1.020
R
PROG
= 34k
V
IN
= 5V
I
BAT
= 2mA
40853f
5
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