SC804A Datasheet, PDF (1/21 Pages) Semtech Corporation – Fully Integrated 4.4V Lithium-Ion Battery Charger System with Timer

SC804A
Fully Integrated 4.4V Lithium-Ion
Battery Charger System with Timer
POWER MANAGEMENT
PRELIMINARY
Description
The SC804A is a fully integrated full-feature, single cell
constant-current/constant-voltage (CC/CV) 4.4V Lithium-
Ion battery charger. With an integrated timer and
complete charge control algorithm, the SC804A is ideal for
stand-alone charger applications. The SC804A contains
programmable pre-charge, fast-charge and termination
current settings. The SC804A can be programmed to
terminate charging based on the output current or the
time-out of the programmable timer. The fast charge
current is typically set with an external resistor, but it can
also be adjusted by applying an analog voltage to the AFC
pin. This feature allows use of a microcontroller to set
charging current via a DAC output.
The SC804A’s 14V input voltage range eliminates the
need for additional protection circuitry required by other
5V chargers to protect against faulty adapters. The
SC804A also incorporates an under-voltage lockout falling
threshold of 3V so that charging will continue if the input
supply goes into a current-limited mode.
Features
Fully integrated charger with FET pass transistor,
reverse-blocking diode, sense resistor, timer, and
thermal protection
Battery voltage controlled to 1% accuracy
Programmable precharge, fastcharge & termination
current over wide range, with analog current control
reference input for design flexibility
Up to 1.5A continuous charge current
Input voltage range from 3V to 14V
Soft-start reduces start-of-charge adapter
load transients
NTC thermistor sense input and adjustable cold
temperature threshold
Adjustable 2 - 6 hour programmable charge timer
0.1μA battery drain current in shutdown and monitor
modes
Small 4mm x 4mm 16 lead MLPQ package
Over-current protection in all modes
Reference ground and battery sense inputs are provided
to eliminate voltage drops during charging due to high
charging currents.
The output voltage to the battery is controlled to within
1% of the programmed voltage. The SC804A can also
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current source for charging nickel-cadmium (NiCd) and
nickel-metal-hydride (NiMH) batteries.
Typical Application Circuit
Over-voltage protection
Remote Kelvin sensing at the battery terminals
Status indicators for charger-present, charger-active,
over-voltage fault, and error notification
Applications
Cellular phones
PDAs
Handheld meters
Charging stations
Handheld computers
Digital cameras
Programmable current
source
Charger VIN
C1
2.2 μF
R3
RT
NTC
OV_FLT
R1 R2
ERROR
14
VCC
13
OVPB
3
IPRGM
7
NTC
4
ITERM
8
FLTB
6
GND
5
RGND
11
CPB
10
CHRGB
12
RTIM
2
CTO
1
BSEN
16
VOUT
15
VOUT
9
AFC
SC804A
Battery
DAC ISET
Red Green
C2
2.2μF
R4
R5
R6
July 18, 2007
1
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