Document
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LTC4085-1
FEATURES
USB Power Manager with Ideal Diode Controller and
4.1V Li-Ion Charger
DESCRIPTIO
■ 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 PowerPathTM When Wall Adapter/USB Input Not Present
■ Load Dependent Charging Guarantees Accurate USB Input Current Compliance
■ 4.1V 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 4.1V Charge Voltage with 0.8% Accuracy ■ C/10 Charge Current Detection Output ■ Tiny (4mm × 3mm × 0.75mm) 14-Lead DFN Package
U APPLICATIO S
■ Portable USB Devices: Cameras, MP3 Players, PDAs
, 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.
The LTC®4085-1 is a USB power manager and Li-Ion 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 LTC4085-1 includes a complete constant-current/ constant-voltage linear charger for single cell Li-Ion batteries. This 4.1V version of the standard LTC4085 is intended for applications which will be operated or stored above approximately 60°C. 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 LTC4085-1 also includes a programmable termination timer, automatic recharging, an end-of-charge status output and an NTC thermistor.
The LTC4085-1 is available in a 14-lead low profile 4mm × 3mm DFN package.
TYPICAL APPLICATIO
5V WALL ADAPTER
INPUT
5V (NOM) FROM USB CABLE VBUS
IIN
4.7μF SUSPEND USB POWER 100mA 500mA SELECT
IN SUSP HPWR
WALL ACPR
OUT
PROG LTC4085-1 GATE
CLPROG
BAT
NTC
CHRG
VNTC 10k
GND TIMER
100k 2k
10k
ILOAD
TO LDOs, REGs, ETC
1k
4.7μF
510Ω
*
+
0.1μF
IBAT
* OPTIONAL - TO LOWER
IDEAL DIODE IMPEDANCE
40851 TA01
Input and Battery Current vs Load Current RPROG = 100k, RCLPROG = 2k
600 IIN
500
CURRENT (mA)
400 ILOAD
300
200
IBAT
(CHARGING)
100
0
IBAT
WALL = 0V
(DISCHARGING)
–100
0 100 200 300 400 500 600
ILOAD (mA)
40851 TA01b
40851fa
1
LTC4085-1
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ABSOLUTE AXI U RATI GS
(Notes 1, 2, 3, 4, 5)
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 (VCC + 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
PI CO FIGURATIO
TOP VIEW
IN 1 OUT 2 CLPROG 3 HPWR 4 SUSP 5 TIMER 6 WALL 7
14 BAT
13 GATE
12 PROG
15
11 CHRG
10 ACPR
9 VNTC 8 NTC
DE PACKAGE 14-LEAD (4mm × 3mm) PLASTIC DFN
TJMAX = 125°C, θJA = 40°C/W EXPOSED PAD (PIN 15) IS GND, MUST BE CONNECTED TO PCB
UW U ORDER I FOR ATIO
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
LTC4085EDE-1#PBF LTC4085EDE-1#TRPBF 40851
14-Lead (4mm × 3mm) Plastic DFN
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/
TEMPERATURE RANGE –40°C to 85°C
ELECTRICAL CHARACTERISTICS The ● indicates specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VIN = 5V, VBAT = 3.7V, HPWR = 5V, WALL = 0V, RPROG = 100k, RCLPROG = 2k, unless otherwise noted.
SYMBOL VIN VBAT IIN
IOUT IBAT
VUVLO ΔVUVLO Current Limit ILIM IIN(MAX) RON
PARAMETER
CONDITIONS
MIN TYP MAX
Input Supply Voltage
IN and OUT
4.35
5.5
Input Voltage
BAT
4.3
Input.