Semtech Debuts Miniature Battery Chargers for Consumer Electronics

Toni McConnel
iApplianceWeb
(00/01/05, 7:55 AM GMT)

Camarillo, Calif. -- The SC805 and SC806 from Semtech Corp. are ultra-small battery charger devices designed for consumer electronics applications including cable chargers, personal media devices and mobile phones.

Both devices charge lithium-ion or lithium-polymer batteries and are packaged in 3mm x 3mm, thermally optimized MLP packages.  The chargers produce up to 1A when operating in continuous charge mode, and during high power-dissipation periods they behave like pulse chargers that regulate the internal die temperature to a safe level.

SC805 and SC806 chargers feature an input voltage range of 3V to 6V for charging from a current-limited adapter.  This feature assures that for high output current designs, the power dissipation can occur in a less-sensitive wall plug adapter rather than in the system’s internal charging circuitry itself.

The SC805 and SC806 are designed with three programmable charge states, including a trickle-charge phase for deeply discharged batteries, a fast-charge phase and a constant-voltage (CV) phase. In addition, the SC805 offers a programmable one- to 10-hour charge timer that protects a system from faulty batteries.  All aspects can be programmed to facilitate a safe and accurate charging profile.

“The high-current level and charging profile flexibility of the SC805 and SC806 are critical key features, and the good news for designers is that all of this comes in a small, less expensive package,” said C.S. Mitter, Semtech's Director of Power Management for Handheld Products. “Add to this an advanced thermal design, and it means these new chargers are well-positioned for the next generation of consumer devices.”

The SC805 and SC806 feature precise line and load regulation, enabling the devices to control battery voltage to 1% accuracy. Once the charger reaches CV mode, it gradually reduces battery output voltage until the termination voltage is reached and then monitors battery voltage levels and initiates a new charge cycle if the battery voltage drops by more than 100mV.

The SC805 and SC806 are fully integrated devices, including charger, FET pass transistor, reverse-blocking diode, sense resistor and thermal protection. In addition to charging lithium-ion or lithium-polymer batteries, the devices can work as general-purpose current sources or as current sources for charging Nickel-Cadmium (NiCd) and Nickel-Metal-Hydride (NiMH) batteries.

The SC805 and SC806 can monitor a negative temperature coefficient pin to detect when the battery is not connected. The SC805 can work with or without a battery, functioning as a low dropout (LDO) regulator when the battery is removed.  This LDO feature is helpful for “bed-of-nails” system testing where a portable device, such as a cell phone, is assembly tested without a battery.

The lead-free package design complies with the European Union’s Restriction on Hazardous Substances in Electrical and Electronic Equipment (RoHS) directive to meet worldwide environmental and regulatory requirements.

Key Features of the SC805 / SC806
•    Highly accurate charge current
•    Tiny 3mm x 3mm 10-lead MLP package
•    Battery voltage controlled to 1% accuracy over the full Industrial temperature range
•    SC805: NTC thermistor safely disables the  charge cycle when temperature is out of range
•    SC805: Contains an auxiliary output pin for external accessories or bootstrap for USB charging
•    0.1µA battery drain current in shutdown and monitor modes
•    Over current protection in all charging modes
•    Automatic loss of battery detection
•    Adapter present, charge status, and no battery output LED drivers

The SC805, ordering code SC805IMLTRT, is available immediately in production quantities and is priced at $1.05 each in 10,000-piece lots. The SC806, ordering code SC806IMLTRT, is available immediately in production quantities and is priced at $1.01 each in 10,000-piece lots. Semtech offers comprehensive design assistance, including field- and factory-based support.

For more information visit www.semtech.com

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