BATTERY VOLTAGE (V)
LTC4068-4.2/LTC4068X-4.2
Standalone Linear
Li-Ion Battery Charger with
Programmable Termination
FEATURES
DESCRIPTIO
Programmable Charge Current Up to 950mA The LTC 4068 is a complete constant-current/constant-
Complete Linear Charger in DFN Package voltage linear charger for single cell lithium-ion batteries.
No MOSFET, Sense Resistor or Blocking Diode Its DFN package and low external component count make
Required the LTC4068 ideally suited for portable applications. Fur-
Thermal Regulation Maximizes Charge Rate thermore, the LTC4068 is designed to work within USB
Without Risk of Overheating* power specifications.
Charges Directly from a USB Port
No external sense resistor or external blocking diode are
Programmable Charge Current Termination
required due to the internal MOSFET architecture. Thermal
Preset 4.2V Charge Voltage with 1% Accuracy
feedback regulates the charge current to limit the die
Charge Current Monitor Output for Gas Gauging*
temperature during high power operation or high ambient
Automatic Recharge
temperature conditions. The charge voltage is fixed at
Charge Status Output
4.2V and the charge current is programmed with a resis-
AC Present Output
tor. The LTC4068 terminates the charge cycle when the
2.9V Trickle Charge Threshold (LTC4068)
charge current drops below the programmed termination
Available Without Trickle Charge (LTC4068X)
threshold after the final float voltage is reached.
Soft-Start Limits Inrush Current
When the input supply (wall adapter or USB supply) is
Low Profile (3mm 3mm 0.75mm) DFN Package
removed, the LTC4068 enters a low current state dropping
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the battery drain current to less than 2A. Other features
APPLICATIO S
include charge current monitor, undervoltage lockout,
Cellular Telephones, PDAs, MP3 Players
automatic recharge and status pins to indicate charge
Bluetooth Applications
termination and the presence of adequate input voltage.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Protected by U.S. Patents, including 6522118.
TYPICAL APPLICATIO
Complete Charge Cycle (750mAh Battery)
700 4.75
CONSTANT
Single Cell Li-Ion Battery Charger with C/5 Termination
CURRENT
600 4.50
CONSTANT
600mA
VOLTAGE
500 4.25
V
IN
V BAT
CC
4.5V TO 6.5V
400 4.00
LTC4068-4.2
1-CELL
+
CHRG
300 3.75
Li-Ion
ITERM
ACPR
BATTERY
EN PROG
200 V = 5V 3.50
825 CC
= 40C/W
GND
JA
1F
1.65k
R = 1.65k
PROG
100 3.25
R = 825
406842 TA01
TERM
T = 25C
A
0 3.00
0 0.25 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25
TIME (HOURS) 406842 TA02
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CHARGE CURRENT (mA)
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ULTC4068-4.2/LTC4068X-4.2
UUW
ABSOLUTE AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
(Note 1)
TOP VIEW
Input Supply Voltage (V ) ....................... 0.3V to 10V
ORDER PART
CC
NUMBER
PROG, ITERM ................................ 0.3V to V + 0.3V
CC
ITERM 1 8 EN
BAT ............................................................. 0.3V to 7V
BAT 2 7 ACPR
LTC4068EDD-4.2
CHRG, ACPR, EN ...................................... 0.3V to 10V 9
CHRG 3 6 V
CC
LTC4068XEDD-4.2
BAT Short-Circuit Duration .......................... Continuous
GND 4 5 PROG
BAT Pin Current ........................................................ 1A
DD PART MARKING
PROG Pin Current ................................................... 1mA
DD PACKAGE
8-LEAD (3mm 3mm) PLASTIC DFN
Maximum Junction Temperature .......................... 125C
T = 125C, = 40C/W (NOTE 3) LBHZ
JMAX JA
Operating Temperature Range (Note 2) .. 40C to 85C
EXPOSED PAD IS GROUND (PIN 9)
LBQB
MUST BE SOLDERED TO PCB
Storage Temperature Range ................. 65C to 125C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T = 25C. V = 5V, unless otherwise noted.
A CC
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V Input Supply Voltage 4.25 6.5 V
CC
I Input Supply Current Charge Mode (Note 4), R = 10k 0.4 1 mA
CC PROG
Standby Mode (Charge Terminated) 200 500 A
Shutdown Mode (EN = 5V, V < V 25 50 A
CC BAT
or V < V )
CC UV
V Regulated Output (Float) Voltage 0C T 85C, 4.3V < V < 6.5V 4.158 4.2 4.242 V
FLOAT A CC
I BAT Pin Current R = 10k, Current Mode 92 100 105 mA
BAT PROG
R = 2k, Current Mode 465 500 535 mA
PROG
Standby Mode, V = 4.2V 2.5 6 A
BAT
Shutdown Mode (EN = 5V, V < V or 1 2 A
CC BAT
V < V )
CC UV
Sleep Mode, V = 0V 1 2 A
CC
I Trickle Charge Current V < V , R = 2k (Note 5) 30 45 60 mA
TRIKL BAT TRIKL PROG
V Trickle Charge Threshold Voltage R = 10k, V Rising (Note 5) 2.8 2.9 3 V
TRIKL PROG BAT
V Trickle Charge Hysteresis Voltage R = 10k (Note 5) 80 mV
TRHYS PROG
V V Undervoltage Lockout Voltage From V Low to High 3.7 3.8 3.92 V
UV CC CC
V V Undervoltage Lockout Hysteresis 150 200 300 mV
UVHYS CC
V EN Pin Input Low Voltage 0.4 0.7 V
EN(IL)
V EN Pin Input High Voltage 0.7 1 V
EN(IH)
R EN Pin Pull-Down Resistor 1.2 2 5 M
EN
V V V Lockout Threshold V from Low to High 70 100 140 mV
ASD CC BAT CC
from High to Low 5 30 50 mV
V
CC
I Charge Termination Current Threshold R = 1k 90 100 110 mA
TERM TERM
R = 5k 17.5 20 22.5 mA
TERM
V PROG Pin Voltage R = 10k, Current Mode 0.93 1 1.07 V
PROG PROG
V CHRG Pin Output Low Voltage I = 5mA 0.35 0.6 V
CHRG CHRG
V ACPR Pin Output Low Voltage I = 5mA 0.35 0.6 V
ACPR ACPR
V Recharge Battery Threshold Voltage V V , 0C T 85C 60 100 140 mV
RECHRG FLOAT RECHRG A
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