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LTC4053-4.2

4053fa

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Cellular Telephones

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Handheld Computers

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Charging Docks and Cradles

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MP3 Players

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Digital Cameras

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Charges Single-Cell Li-Ion Batteries Directly from

USB Port

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Thermal Regulation Maximizes Charge Rate

without Risk of Overheating*

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Programmable Charge Current with ±7% Accuracy

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Low Dropout Operation

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No External MOSFET, Sense Resistor or Blocking

Diode Required

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Programmable Charge Termination Timer

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Preset Charge Voltage with ±1% Accuracy

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C/10 Charge Current Detection Output

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AC Present Logic Output

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25µA Supply Current in Shutdown Mode

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Automatic Recharge

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Charge Current Monitor Useful for Gas Gauging

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Thermistor Input for Temperature Qualified Charging

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Available in 10-pin thermally enhanced MSOP and

low profile (0.75mm) 3mm × 3mm DFN packages

USB Compatible

Lithium-Ion Battery Charger

with Thermal Regulation

The LTC

4053 is a standalone linear charger for lithium-

ion batteries that can be powered directly from a USB port.

The IC contains an on-chip power MOSFET and eliminates

the need for an external sense resistor and blocking diode.

Thermal regulation automatically adjusts charge current

to limit die temperature during high power or high ambient

temperature conditions. This feature protects the end

product and the LTC4053 from thermal stress while the IC

charges the battery at maximum rate without interruption.

The charge current and charge time can be set externally

with a single resistor and capacitor, respectively. When

the input supply (wall adapter or USB supply) is removed,

the LTC4053 automatically enters a low current sleep

mode, dropping the battery drain current to less than 5µA.

The LTC4053 also includes NTC temperature sensing,

C/10 detection circuitry, AC present logic, low battery

charge conditioning (trickle charging) and shutdown (25µA

supply current).

The LTC4053 is available in 10-pin thermally enhanced

MSOP and low profile (0.75mm) DFN packages.

, LTC and LT are registered trademarks of Linear Technology Corporation.

USB PORT

4.35V TO 5.5V

4.7µF

4053TA01

USB CONTROL

µC

Li-Ion

BATTERY

SYSTEM

LOAD

0.1µF

15k

100mA/

500mA

SUSPEND

3.74k

SHDN

GND NTC

756

PROG

LTC4053-4.2

BAT

TIMER

USB Powered Standalone Li-Ion Charger

Protected by U.S. Patents including 6522118, 6700364.

Charge Current vs Input Voltage

(V)

4.0

BAT

(mA)

600

500

400

300

200

100

4.5 5.0

4053 G04

5.5

= 25°C

PROG

= 3k

BAT

= 3.95V

BAT

= 4.15V

BAT

= 4.05V

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

Summary of content (16 pages)

PAGE 1
LTC4053-4.2 USB Compatible Lithium-Ion Battery Charger with Thermal Regulation U FEATURES DESCRIPTIO ■ The LTC®4053 is a standalone linear charger for lithiumion batteries that can be powered directly from a USB port. The IC contains an on-chip power MOSFET and eliminates the need for an external sense resistor and blocking diode. Thermal regulation automatically adjusts charge current to limit die temperature during high power or high ambient temperature conditions.
PAGE 2
LTC4053-4.2 W W U W ABSOLUTE AXI U RATI GS (Note 1) Input Supply Voltage (VCC) ....................................... 7V BAT ........................................................................... 7V NTC, SHDN, TIMER, PROG ............ –0.3V to VCC + 0.3V CHRG, FAULT, ACPR .................................. –0.3V to 7V BAT Short-Circuit Duration .......................... Continuous BAT Current (Note 2) ............................................. 1.3A PROG Current (Note 2) .....................
PAGE 3
LTC4053-4.2 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V SYMBOL PARAMETER CONDITIONS VPROG PROG Pin Voltage RPROG = 3k, IPROG = 500µA ICHRG CHRG Pin Weak Pulldown Current VCHRG = 1V 30 50 µA VCHRG CHRG Pin Output Low Voltage ICHRG = 5mA 0.35 0.6 V VACPR ACPR Pin Output Low Voltage IACPR = 5mA 0.35 0.6 V VFAULT FAULT Pin Output Low Voltage IFAULT = 5mA 0.35 0.
PAGE 4
LTC4053-4.2 U W TYPICAL PERFOR A CE CHARACTERISTICS Battery Regulation Voltage vs Battery Charge Current 4.24 VCC = 5V TA = 25°C RPROG = 3k 4.21 VBAT (V) 4.20 VBAT (V) Battery Regulation Voltage vs VCC 4.19 4.210 4.22 4.208 4.20 4.206 4.18 4.204 4.16 4.202 VBAT (V) 4.22 Battery Regulation Voltage vs Temperature 4.14 4.12 4.18 4.08 50 100 150 200 250 300 350 400 450 500 IBAT (mA) 4.06 –50 4.192 4.190 0 25 50 75 TEMPERATURE (°C) –25 100 4053 G01 4 450 VBAT = 4.15V 100 4.
PAGE 5
LTC4053-4.2 U W TYPICAL PERFOR A CE CHARACTERISTICS PROG Pin Voltage vs Charge Current 1.515 1.515 1.6 VCC = 5V TA = 25°C RPROG = 3k 1.4 PROG Pin Voltage vs Temperature Constant Current Mode PROG Pin Voltage vs VCC Constant Current Mode VBAT = 3.5V TA = 25°C RPROG = 3k 1.510 VCC = 5V VBAT = 4V RPROG = 3k 1.510 1.505 0.8 0.6 VPROG (V) 1.505 1.0 VPROG (V) VPROG (V) 1.2 1.500 1.500 1.495 1.495 1.490 1.490 0.4 0.2 1.
PAGE 6
LTC4053-4.2 U U U PI FU CTIO S CHRG: Open-Drain Charge Status Output. When the battery is being charged, the CHRG pin is pulled low by an internal N-channel MOSFET. When the charge current drops to 10% of the full-scale current, the N-channel MOSFET latches off and a 30µA current source is connected from the CHRG pin to ground. The C/10 latch can be cleared by grounding the SHDN pin, momentarily, or toggling VCC.
PAGE 7
LTC4053-4.2 W W SI PLIFIED BLOCK DIAGRA VCC 2 – 105°C D1 TA D2 + TDIE M2 ×1 D3 M1 ×1000 + – MA 9 30µA NTC 6 BAT R1 NTC MP + VA R2 – CA + – 2.485V REF HOT COLD DISABLE CHRG 1 STOP SHDN 8 SHDN C/10 R3 30µA 1.5V LOGIC ACPR 10 R4 ACPR 0.15V + C2 C/10 FAULT 3 R5 – FAULT CHARGE COUNTER C3 OSCILLATOR – 2.
PAGE 8
LTC4053-4.2 U OPERATIO The LTC4053 is a linear battery charger designed primarily for charging single cell lithium-ion batteries. Featuring an internal P-channel power MOSFET, the charger uses a constant-current/constant-voltage charge algorithm with programmable current and a programmable timer for charge termination. Charge current can be programmed up to 1.25A with a final float voltage accuracy of ±1%.
PAGE 9
LTC4053-4.2 U W U U APPLICATIO S I FOR ATIO Undervoltage Lockout (UVLO) An internal undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until VCC rises above the undervoltage lockout threshold. The UVLO circuit has a built-in hysteresis of 150mV. Furthermore, to protect against reverse current in the power MOSFET, the UVLO circuit keeps the charger in shutdown mode if VCC falls to within 35mV of the battery voltage.
PAGE 10
LTC4053-4.2 U W U U APPLICATIO S I FOR ATIO Programming The Timer The programmable timer is used to terminate the charge cycle. The timer duration is programmed by an external capacitor at the TIMER pin. The total charge time is: Table 1. FAULT CHRG High Low Charge cycle has started, C/10 has not been reached and charging is proceeding normally.
PAGE 11
LTC4053-4.2 U W U U APPLICATIO S I FOR ATIO V+ VDD VCC 7/8 VCC 8 VCC 400k LTC4053 CHRG 3 2k µPROCESSOR – RHOT 1% OUT TOO COLD + NTC IN 4053 F03 RNTC 10k TOO HOT – Figure 3. Microprocessor Interface full-scale current (C/10), the N-channel MOSFET is turned off and a 30µA current source is connected to the CHRG pin. The IN pin will then be pulled high by the 2k pull-up. By forcing the OUT pin to a high impedance state, the current source will pull the pin low through the 400k resistor.
PAGE 12
LTC4053-4.2 U W U U APPLICATIO S I FOR ATIO NTC Trip Point Errors When a 1% resistor is used for RHOT, the major error in the 50°C trip point is determined by the tolerance of the NTC thermistor. A typical 10k NTC thermistor has a ±10% tolerance. By looking up the temperature coefficient of the thermistor at 50°C, the tolerance error can be calculated in degrees centigrade. Consider the Vishay NTHS0603N02N1002J thermistor which has a temperature coefficient of –3.3%/°C at 50°C.
PAGE 13
LTC4053-4.2 U W U U APPLICATIO S I FOR ATIO Regardless of mode, the voltage at the PROG pin is proportional to the current being delivered to the battery. Power Dissipation The conditions that cause the LTC4053 to reduce charge current due to the thermal protection feedback can be approximated by considering the power dissipated in the IC.
PAGE 14
LTC4053-4.2 U W U U APPLICATIO S I FOR ATIO PROG pin. With no additional capacitance on the PROG pin, stability is acceptable with program resistor values as high as 50k. However, additional capacitance on this node reduces the maximum allowed program resistor. The pole frequency at the PROG pin should be kept above 500kHz.
PAGE 15
LTC4053-4.2 U PACKAGE DESCRIPTIO MSE Package 10-Lead Plastic MSOP (Reference LTC DWG # 05-08-1663) BOTTOM VIEW OF EXPOSED PAD OPTION 2.794 ± 0.102 (.110 ± .004) 5.23 (.206) MIN 0.889 ± 0.127 (.035 ± .005) 1 2.06 ± 0.102 (.081 ± .004) 1.83 ± 0.102 (.072 ± .004) 2.083 ± 0.102 3.2 – 3.45 (.082 ± .004) (.126 – .136) 10 0.50 0.305 ± 0.038 (.0197) (.0120 ± .0015) BSC TYP RECOMMENDED SOLDER PAD LAYOUT 3.00 ± 0.102 (.118 ± .004) (NOTE 3) 3.00 ± 0.102 (.118 ± .004) NOTE 4 4.90 ± 0.15 (1.93 ± .006) 0.
PAGE 16
LTC4053-4.2 U TYPICAL APPLICATIO S USB/Wall Adapter Power Li-Ion Battery Charger 5V WALL ADAPTER LTC4053-4.2 BAT 2 USB POWER IBAT 9 1µF VCC + Li-Ion CELL 1Ω 4.7µF 4 1k TIMER SHDN 8 SUSPEND GND NTC PROG 5 7 6 µC 3.74k 0.1µF 100mA/ 500mA 15k 4053 F06 Li-Ion Battery Charger with Reverse Polarity Input Protection 2 5V WALL ADAPTER 8 4.7µF 4 LTC4053-4.2 9 VCC BAT VIN = 5V IBAT = 1A 1k PROG GND NTC 0.