Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsPMICsPMIC - battery management Charge management Li-Ion DFN 6 (2x2) Surface-mount

LTC4065/LTC4065A

4065fb

■

Wireless PDAs

■

Cellular Phones

■

Portable Electronics

Standalone 750mA Li-Ion

Battery Charger in 2 × 2 DFN

■

Complete Linear Charger in 2mm

××

× 2mm DFN

Package

■

C/10 Charge Current Detection Output

■

Timer Termination

■

Charge Current Programmable up to 750mA with

5% Accuracy

■

No External MOSFET, Sense Resistor or Blocking

Diode Required

■

Preset 4.2V Float Voltage with 0.6% Accuracy

■

Constant-Current/Constant-Voltage Operation with

Thermal Feedback to Maximize Charging Rate

Without Risk of Overheating

■

ACPR Pin Indicates Presence of Input Supply

(LTC4065A Only)

■

Charge Current Monitor Output for Gas Gauging

■

Automatic Recharge

■

Charges Single Cell Li-Ion Batteries Directly from

USB Port

■

20µA Supply Current in Shutdown Mode

■

Soft-Start Limits Inrush Current

■

Tiny 6-Lead (2mm × 2mm) DFN Package

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

510Ω

R2*

1Ω

500mA

4065 TA01

4.2V

Li-Ion

BATTERY

4.3V TO 5.5V

1µF

*SERIES 1Ω RESISTOR ONLY NEEDED FOR INDUCTIVE INPUT SUPPLIES

LTC4065

CHRG

BAT

PROG

GND

The LTC

4065 is a complete constant-current/constant-

voltage linear charger for single-cell lithium-ion batteries.

Its 2mm × 2mm DFN package and low external component

count make the LTC4065 especially well-suited for por-

table applications. Furthermore, LTC4065 is specifically

designed to work within USB power specifications.

The CHRG pin indicates when charge current has dropped

to ten percent of its programmed value (C/10). An internal

timer terminates charging according to battery manufac-

turer specifications.

No external sense resistor or blocking diode is required

due to the internal MOSFET architecture. Thermal feed-

back regulates charge current to limit the die temperature

during high power operation or high ambient temperature

conditions.

When the input supply (wall adapter or USB supply) is

removed, the LTC4065 automatically enters a low current

state, dropping battery drain current to less than 1µA. With

power applied, LTC4065 can be put into shutdown mode,

reducing the supply current to less than 20µA.

The full-featured LTC4065 also includes automatic re-

charge, low-battery charge conditioning (trickle charg-

ing), soft-start (to limit inrush current) and an open-drain

status pin to indicate the presence of an adequate input

voltage (LTC4065A only).

The LTC4065 is available in a tiny 6-lead, low profile

(0.75mm) 2mm × 2mm DFN package.

Standalone Li-Ion Battery Charger

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

All other trademarks are the property of their respective owners.

Summary of content (16 pages)

PAGE 1
LTC4065/LTC4065A Standalone 750mA Li-Ion Battery Charger in 2 × 2 DFN U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Complete Linear Charger in 2mm × 2mm DFN Package C/10 Charge Current Detection Output Timer Termination Charge Current Programmable up to 750mA with 5% Accuracy No External MOSFET, Sense Resistor or Blocking Diode Required Preset 4.2V Float Voltage with 0.
PAGE 2
LTC4065/LTC4065A W W W AXI U U ABSOLUTE RATI GS U U W PACKAGE/ORDER I FOR ATIO (Note 1) VCC t < 1ms and Duty Cycle < 1% ................. – 0.3V to 7V Steady State ........................................... – 0.3V to 6V BAT, CHRG ................................................. –0.3V to 6V EN (LTC4065), ACPR (LTC4065A) .. –0.3V to VCC + 0.3V PROG.............................................. –0.3V to VCC + 0.3V BAT Short-Circuit Duration ...........................Continuous BAT Pin Current .....
PAGE 3
LTC4065/LTC4065A ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = 25°C. VCC = 5V, VBAT = 3.8V, VEN = 0V (LTC4065 only) unless otherwise specified. (Note 2) SYMBOL PARAMETER CONDITIONS IPROG PROG Pin Pull-Up Current (LTC4065A) VPROG > 1V MIN VMS,PROG PROG Shutdown Threshold Voltage (LTC4065A Only) VPROG Rising tSS Soft-Start Time ITRKL Trickle Charge Current VBAT = 2V, RPROG = 2k (0.
PAGE 4
LTC4065/LTC4065A U W TYPICAL PERFOR A CE CHARACTERISTICS Battery Regulation (Float) Voltage vs Battery Charge Current Regulated Output (Float) Voltage vs Supply Voltage 4.24 4.23 4.23 4.22 4.22 4.22 4.21 4.21 4.21 VCC = 5V TA = 25°C RPROG = 2k VFLOAT (V) 4.23 4.20 4.19 VFLOAT (V) 4.24 4.24 VFLOAT (V) Battery Regulation (Float) Voltage vs Temperature 4.20 4.19 4.20 4.19 4.18 4.18 4.18 4.17 4.17 4.17 4.16 100 0 200 300 IBAT (mA) 400 4.
PAGE 5
LTC4065/LTC4065A U W TYPICAL PERFOR A CE CHARACTERISTICS Manual Shutdown Threshold Voltage vs Temperature (LTC4065) Undervoltage Lockout Threshold Voltage vs Temperature Manual Shutdown Supply Current vs Temperature 1.0 4.0 3.8 40 0.9 30 RISE RISE 3.3 FALL 3.0 0.8 ICCMS (µA) VMS (V) 3.5 VCC (V) VCC = 5V VEN = 5V FALL 0.7 20 10 0.6 2.8 2.5 –50 –25 50 0 25 TEMPERATURE (°C) 75 0.5 –50 100 50 25 0 TEMPERATURE (°C) –25 75 4065 G16 60 50 60 IBAT (mA) 30 20 20 10 2.5 3 3.
PAGE 6
LTC4065/LTC4065A U W TYPICAL PERFOR A CE CHARACTERISTICS Timer Accuracy vs Temperature Timer Accuracy vs Supply Voltage 2.0 VCC = 5V 0 1.5 –1 1.0 TIMER ACCURACY (%) TIMER ACCURACY (%) 1 –2 –3 –4 –5 TA = 25°C 0.5 0 –0.5 –1.0 –1.5 –6 –7 –50 –2.0 –25 0 50 25 TEMPERATURE (°C) 75 100 4 5 4.5 5.5 SUPPLY VOLTAGE (V) 4065 G19 4065 G18 PROG Pin Shutdown Threshold vs Temperature (LTC4065A Only) 5.0 6 PROG Pin Shutdown Voltage vs Supply Voltage (LTC4065A Only) 5.0 VCC = 5V TA = 25°C 4.
PAGE 7
LTC4065/LTC4065A U U U PI FU CTIO S GND (Pin 1): Ground. CHRG (Pin 2): Open-Drain Charge Status Output. The charge status indicator pin has three states: pull-down, pulse at 2Hz and high impedance state. This output can be used as a logic interface or as an LED driver. 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 CHRG pin is forced to a high impedance state.
PAGE 8
LTC4065/LTC4065A W W SI PLIFIED BLOCK DIAGRA S VCC 4 VCC + TDIE D3 TA M2 ×1 EN UVLO – 3.6V + RENB SHUTDOWN C1 D1 D2 – 0.82V BAT – + R1 CA – R3 + + 1V – C/10 1.2V MP R4 0.1V R2 CHRG VA + 0.1V 3 + MA 1.2V REF PROG 2 C2 M1 ×1000 – 5 + – 115°C CHARGE CONTROL R5 2.9V BAT + LOGIC ENABLE – COUNTER LOBAT SHUTDOWN PROG 6 GND 1 OSCILLATOR 4056 F01a RPROG Figure 1a.
PAGE 9
LTC4065/LTC4065A W W SI PLIFIED BLOCK DIAGRA S VCC 4 VCC + D3 C2 5 ACPR – + TDIE – 115°C TA 3.6V M2 ×1 + M1 ×1000 D1 D2 C3 BAT – + MA R1 CA – R3 + + 1V – C/10 MP R4 1.2V 0.1V 2 CHRG R2 R5 2.9V BAT CHARGE CONTROL ENABLE – + VA + 0.1V 3 + – – 1.2V REF PROG VBAT + 80mV LOGIC + LOBAT SHUTDOWN C1 4V – OSCILLATOR PROG 6 COUNTER GND 1 4056 F01b RPROG Figure 1b.
PAGE 10
LTC4065/LTC4065A U OPERATIO typical, not worst-case, ambient temperatures for a given application with the assurance that the charger will automatically reduce the current in worst-case conditions. The charge cycle begins when the following conditions are met: the voltage at the VCC pin exceeds 3.6V and approximately 80mV above the BAT pin voltage, a program resistor is present from the PROG pin to ground and the EN pin (LTC4065 only) is pulled below the shutdown threshold (typically 0.82V).
PAGE 11
LTC4065/LTC4065A U OPERATIO Once the charge cycle terminates, the LTC4065 continuously monitors the BAT pin voltage using a comparator with a 2ms filter time. When the average battery voltage falls below 4.1V (which corresponds to 80% to 90% battery capacity), a new charge cycle is initiated and a 2.25 hour timer begins. This ensures that the battery is kept at, or near, a fully charged condition and eliminates the need for periodic charge cycle initiations.
PAGE 12
LTC4065/LTC4065A U OPERATIO UVLO ENABLE POWER ON NO UVLO MODE NO IS EN > SHUTDOWN THRESHOLD? IF VCC > 3.6V AND VCC > VBAT + 80mV? YES YES CHRG HIGH IMPEDANCE SHUTDOWN MODE CHRG HIGH IMPEDANCE VBAT ≤ 2.9V 2.9V < VBAT < 4.1V TRICKLE CHARGE MODE FAST CHARGE MODE 1/10 FULL CHARGE CURRENT CHRG STRONG PULL-DOWN FULL CHARGE CURRENT CHRG STRONG PULL-DOWN 1/4 CHARGE CYCLE (1.125 HOURS) NO RECHARGE IS VBAT < 4.1V? IS VBAT < 2.
PAGE 13
LTC4065/LTC4065A U W U U APPLICATIO S I FOR ATIO Undervoltage Charge Current Limiting (UVCL) The LTC4065/LTC4065A includes undervoltage charge (∆VUVCL1) current limiting that prevents full charge current until the input supply voltage reaches approximately 200mV above the battery voltage. This feature is particularly useful if the LTC4065 is powered from a supply with long leads (or any relatively high output impedance).
PAGE 14
LTC4065/LTC4065A U W U U APPLICATIO S I FOR ATIO length, however, may add enough series inductance to require a bypass capacitor of at least 1µF from BAT to GND. Furthermore, a 4.7µF capacitor with a 0.2Ω to 1Ω series resistor from BAT to GND is required to keep ripple voltage low when the battery is disconnected. High value capacitors with very low ESR (especially ceramic) may reduce the constant-voltage loop phase margin.
PAGE 15
LTC4065/LTC4065A U W U U APPLICATIO S I FOR ATIO Furthermore, the voltage at the PROG pin will change proportionally with the charge current as discussed in the Programming Charge Current section. It is important to remember that LTC4065/LTC4065A applications do not need to be designed for worst-case thermal conditions since the IC will automatically reduce power dissipation when the junction temperature reaches approximately 115°C.
PAGE 16
LTC4065/LTC4065A RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1734 Lithium-Ion Linear Battery Charger in ThinSOTTM Simple ThinSOT Charger, No Blocking Diode, No Sense Resistor Needed LTC1734L Lithium-Ion Linear Battery Charger in ThinSOT Low Current Version of LTC1734, 50mA ≤ ICHRG ≤ 180mA LTC4002 Switch Mode Lithium-Ion Battery Charger Standalone, 4.