SC820
Adapter/USB Dual Input
Single-cell Li-ion Charger
POWER MANAGEMENT
Features
Description
Input voltage protection — 30V
The SC820 is a dual input (adapter/USB) linear single-cell
Li-ion battery charger in an 8 lead 2×2mm MLPD ultra-thin
package. Both inputs will survive sustained input voltage
up to 30V to protect against hot plug overshoot and faulty
charging adapters.
Adapter input automatically selected over USB
Constant voltage — 4.2V, 1% regulation
Charging by current and voltage regulation (CC/CV)
Thermal limiting of charge current
Programmable battery-dependent currents (adapter-
sourced fast-charge & pre-charge, termination)
Programmable source-limited currents (USB-sourced
fast-charge & pre-charge)
Current-limited adapter support — reduces power dis-
sipation in charger IC
USB input limits charge current — prevents Vbus
overload
Instantaneous CC-to-CV transition for faster charging
Three termination options — float-charge, automatic
re-charge, or forced re-charge to keep the battery
topped-off after termination without float-charging
Soft-start — reduces load transients
High operating voltage range — permits use of
unregulated adapters
Complies with CCSA YD/T 1591-2006
Charging begins automatically when a valid input source
is applied to either input. The adapter input is selected
when both input sources are present.
Thermal limiting protects the SC820 from excessive power
dissipation when charging from either source. The SC820
can be programmed to turn off when charging is complete
or to continue operating as an LDO regulator while float-
charging the battery.
The adapter input charges with an adapter operating in
voltage regulation or in current limit to obtain the lowest
possible power dissipation by pulling the VAD input
voltage down to the battery voltage. The VUSB input
dynamically limits load current to automatically prevent
over-loading the USB Vbus supply.
Space saving 2×2×0.6 (mm) MLPD package
Pb free, Halogen free, and RoHS/WEEE compliant
Charge current programming requires two resistors. One
determines battery-capacity dependent currents: adapter
input fast-charge current, pre-charge current, and charge
termination current. The other independently determines
input-limited USB charging currents: USB input fast-
charge and pre-charge current.
Applications
Mobile phones
MP3 players
GPS handheld receivers
Typical Application Circuit
SC820
Battery
Pack
Device
Load
VADAPTER
VAD
ENB
BAT
USB Vbus
VUSB
STATB
GND
2.2 μF
IPRGM
IPUSB
2.2 μF
2.2 μF
© 2009 Semtech Corporation
September 17, 2009
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