SHOUDING
600mA
Standalone Linear
Li-Ion Battery Charger with
SD8055
Thermal Regulation in ThinSOT
General Description
The SD8055 is a complete constant-current/constant-
voltage linear charger for single cell lithium-ion batteries.
Its ThinSOT package and low external component
count make the SD8055 ideally suited for portable
applications. Furthermore, the SD8055 is s pecifically
designed to work within USB power specifications.
No external sense resistor is needed, and no blocking
diode is required due to the internal MOSFET
architecture. Thermal feedback regulates the charge
current to limit the die temperature during high power
operation or high ambient temperature. The charge
voltage is fixed at 4.2V, and the charge current can be
programmed externally with a single resistor. The
SD8055 automatically terminates the charge cycle when
the charge current drops to 1/10th the programmed
value after the final float voltage is reached. When the
input supply (wall adapter or USB supply) is removed,
the SD8055 automatically ent ers a low current state,
dropping the battery drain current to less than 2µA. The
SD8055 can be put into shut down mode, reducing he
supply current to 25µA.Other features include charge
current monitor, undervoltage lockout, automatic
recharge and a status pin to indicate charge termination
and the presence of an input voltage.
Features
Programmable Charge Current Up to 600mA
No MOSFET, Sense Resistor or Blocking Diode
Required
Complete Linear Charger in ThinSOT
Package for
Single Cell Lithium-ion Batteries
Constant-Current/Constant-Voltage Operation
with Thermal Regulation to Maximize Charge
Rate Without Risk of Overheating
Charges Single Cell Li-Ion Batteries Directly
from USB Port
Preset 4.2V Charge Voltage with ± 1.5% Accuracy
Charge Current Monitor Output for Gas
Gauging
Automatic Recharge
Soft-Start Limits Inrush Current
Available in 5-Lead SOT-23 Package
2.9V Trickle Charge Threshold
C/10 Charge Termination
25uA Supply Current in Shutdown
2.9V Trickle Charge Threshold
Applications
Portable Media Players/MP3 players
Cellular and Smart mobile phone
Charging Docks and Cradles
Bluetooth Applications
Ordering Information
SD8055
□ □
□
F:PB-Free
Marking Information
Please see website.
Package
B5:SOT23-5
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SHOUDING
Functional Pin Description
SD8055
SD8055
(TSOT23-5)
PIN
SD8055
DESCRIPTION
Open-Drain Status Output
Ground
Charge Current Output
Positive Input Supply Voltage
Charge Current Program, Charge Current Monitor and
Shutdown Pin.
CHRG
GND
BAT
VCC
PROG
1
2
3
4
5
Pin Functions
CHRG (PIN 1):
Open-Drain Charge Status Output. When the battery is charging, the CHRG pin is pulled low by an internal
N-channel MOSFET. When the charge cycle is completed, CHRG is forced high impedance.
GND (PIN 2):
Ground.
BAT (PIN 3):
Charge Current Output. Provides charge current to the battery and regulates the final float voltage to 4.2V. An
internal precision resistor divider from this pin sets the float voltage which is disconnected in shutdown mode.
should be bypassed with at l
VCC (PIN 4):
Positive Input Supply Voltage. Provides power to the charger. V
CC
can range from 4.35V to 5.5V and
should be bypassed with at l
least a 1µF capacitor. When V
CC
drops to within 30mV of the BAT pin voltage, the
SD8055 enters shutdown mode, dropping IBAT to less than 2µA.
PROG (PIN 5):
Charge Current Program, Charge Current Monitor and Shutdown Pin. The charge current is
programmed by connecting a 1% resistor, R
PROG
, to ground. When charging in constant-current mode, this pin servos
to 1V. In all modes, the voltage on this pin can be used to measure the charge current using the following formula:
The PROG pin can also be used to shutdown the charger. Disconnecting the program resistor from ground allows a
3µA current to pull the PROG pin high. When it reaches the 1.94V shutdown threshold voltage, the charger enters
shutdown mode, charging stops and the input supply current drops to 25µA. This pin is also clamped to
approximately 2.4V. Driving this pin to voltages beyond the clamp voltage will draw currents as high as1.5mA.
Reconnecting R
PROG
to ground will return the charger to normal operation.
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Electrical Characteristics
(Over 0C
≤TJ ≤125°C
and recommended supply voltage)
SD8055
Note 1: Absolute Maximum Ratings are those values beyond which the life of the device may be impaired.
Note 2: The SD8055 are guaranteed to meet performance specifications from 0℃ to 70℃. Specifications over the
-40℃ to 85℃ operating temperature range are assured by design, characterization and correlation with statistical
process controls.
Note 3: See Thermal Considerations.
Note 4: Supply current includes PROG pin current (approximately 100µA) but does not include any current delivered to
the battery through the BAT pin (approximately 100mA).
Note 5: This parameter is not applicable to the SD8055X.
Note 6: I
TERM
is expressed as a fraction of measured full charge current with indicated PROG resistor.
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