SC805 Datasheet, PDF (1/15 Pages) Semtech Corporation – Miniature Integrated High Current Lithium-Ion Battery Charger

SC805
Miniature Integrated High Current
Lithium-Ion Battery Charger
POWER MANAGEMENT
Description
Features
The SC805 is a fully integrated, single cell, constant-cur-
rent (CC)/constant-voltage (CV) Lithium-Ion battery
charger in a tiny 3x3 mm thermally enhanced lead free
MLP package. The SC805 can operate as a stand-alone
charger or in conjunction with a Power Management Con-
troller (PMIC).
The SC805 has a pre-charge function for trickle charging
deeply discharged batteries. The fast charge current is
enabled automatically when the battery voltage reaches
the required threshold. When the battery reaches the
constant voltage or CV portion of the charge curve the
SC805 switches to CV regulation mode. In this mode
the output current decays as the battery charges until
the termination current is reached and the SC805 sig-
nals the charge cycle is complete. The SC805 can be
configured to continue charging for a predetermined time
before turning off, or to turn off immediately upon termi-
nation. After turning off its output, The SC805 enters
monitor mode. If the battery voltage drops by 100mV
from the CV voltage a new charge cycle will begin. The
timer function also protects against charging faulty bat-
teries by turning off if the pre-charge time exceeds 1/4
of the total programmed charge duration.
‹ Fully integrated charger with FET pass transistor,
reverse-blocking diode, sense resistor and thermal
protection
‹ High Accuracy Charge Current*
‹ Tiny 3mm x 3mm 10 lead MLP package
‹ Programmable precharge, fastcharge & termination
current
‹ Battery voltage controlled to 1% accuracy
‹ Built in timer for protection and complete charging
‹ NTC interface with battery detection
‹ Soft-start for step load and adaptor plug-in
‹ Up to 1A continuous charge current
‹ Input voltage range from 3V to 6V allows seamless
charging from current limited adapter
‹ Provides adapter voltage VCCIL to power external
accessories
‹ Battery Present detection and output indicator
‹ Operates in charger or LDO-mode without battery
‹ 0.1µA battery drain current in shutdown and
monitor modes
‹ Over current protection in all charging modes
‹ CHRGB output communicates charging and end of
charge cycle
The SC805 also provides battery detection, and a bat-
tery NTC thermistor interface to disable charging when
*Patent Pending
the battery temperature exceeds safe-to-charge limits. _Applications
The SC805 can also function as a general purpose cur-
rent source or as a current source for charging nickel-
cadmium (NiCd) and nickel-metal-hydride (NiMH) batter-
ies.
Typical Application Circuit
‹ Cellular phones
‹ PDA’s
‹ Handheld meters
‹ Charging stations
‹ USB chargers
‹ Digital cameras
‹ Programmable current source
CHARGER VIN
SC805 typical Application Circuit
SC805
C1
1uF
D1
LED
R2
3.01k
1
2
7
8
9
VCC
VOUT
VCCIL CHRGB
EN/NTC ITERM
NOBAT IPRGM
RTIME GND
3
10
5
4
6
Adapter
Present
Indicator
R1
3.01k
RT1
Thermistor
t
R3
3.01k
R4
3.01k
R5
3.01k
Charge
Complete
Indicator
D2
LED
R6
1k
D3
LED
R7
1k
BATTERY
C1
2.2uF
Charging
Indicator
August 22, 2005
1
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