Semtech Announces CMOS Dual, Low Noise, Linear Regulator Ideal For Portable Applications

Semtech Corp. (Nasdaq: SMTC), a leading supplier of analog and mixed-signal semiconductors for communications, computers, and industrial equipment, today announced the SC801 highly integrated, high-current lithium-ion (Li-ion) battery-charger chip. By packing the feature-rich, programmable Li-ion battery-charging system into a tiny, thermally-efficient package, the SC801 critically reduces cost, design time, and circuit board real estate.

As a result, the SC801 makes a highly attractive choice for use in cellular phones, personal digital assistants, digital cameras, handheld computers, and other portable and battery-powered electronic products. The SC801 works equally well as a charging system for nickel-cadmium and nickel-metal-hydride batteries or as a general-purpose programmable current source.

"Portable electronic products impose severe space and cost constraints and narrow design windows. The Lithium-ion batteries used in these products require precise charging algorithms for safe operation and long battery life," said Eddie Yeow, Director of Portable Power Management Products at Semtech. "The distinction of the SC801 is its ability to meet all of the above requirements with a single 4mm X 4mm integrated chip."

High integration is at the core of the SC801's capacity to cut cost, space and design time of a Li-ion battery charger. Specifically, the chip combines a controller, thermally protected power MOSFET, reverse blocking diode, and a sense resistor onto a single die mounted in a 1.0-mm-high, 4-x-4mm microleaded package (MLP). To foster heat dissipation and protect surrounding components, the package, which touts an impressive 50 C/W junction-to-ambient thermal resistance, features an exposed copper heat sink that makes direct contact with a printed-circuit board pad. Additional space savings are gained by the chip's use of small input and output filter capacitors.

Among the noteworthy performance features of the SC801 is its fast-charge current of up to 1.5A. Moreover, to avoid overheating a fully discharged battery, the SC801 automatically invokes a precharge mode, limiting charge current to 10mA to 125mA for batteries under 2.8V, only switching to its fast charge mode after the battery voltage reaches the 2.8V threshold.

Several functional features make the SC801 easy to use in a wide range of products and designs. For example, the SC801 accepts input voltages from 4.2 to 14V to yield a selectable output of either 4.1V or 4.2V regulated to 1% accuracy. Also, the chip lets designers customize the charge pattern by offering programmable precharge, fast charge, and charge termination currents. As a result, charging can be done safely over the full industrial temperature range.

Battery monitoring and protection features are among the other strengths of the SC801. For instance, output flags can directly drive LEDs to indicate overvoltage fault, charge (adapter) present, and charging or end-of-charging conditions. Also, a battery-in-place indication notes whether a battery is present and, if not, configures the SC801 to work as a conventional low dropout (LDO) voltage regulator to correctly power the system.

Other monitoring functions include Kelvin sensor inputs to monitor the temperature of the voltage at the battery terminals and an output current mode monitor for direct connection to an analog-to-digital converter or microcontroller. In this way, a microcontroller can restart the charging process in the case of a low battery voltage, inadequate charging rates, or if charging is interrupted.

The SC801 also features soft-start operation in the event of step loads or, for when a power adapter is connected, step inputs. All charge modes are protected against overcurrent and overvoltage conditions. To save power, a key requirement in portable electronic products, the SC801 draws just 1 A in monitor and shutdown modes.

Key Features of the SC801 Li-Ion Battery Charger Chip

• Integrates charge controller, thermally protected MOSFET, reverse blocking diode, and sense resistor

• Space-saving, thermally-efficient, 1.0-mm-high, max., 4-x-4-mm microleaded package (MLP)

• Programmable precharge, fast charge, and charge termination currents

• Overvoltage, charge present, and charge/end-of-charge LED outputs

• Battery voltage and current sensing

• Battery-in-place indicator

• Soft-start for step loads and step inputs

• Overvoltage and overcurrent protected

• Draws only 1µA in monitor and shutdown modes

Pricing and Availability

The SC801 fully integrated Lithium-ion battery-charger chip packaged in a 4-x-4mm MLP is available now through Semtech's network of direct sales representatives and distributors. Pricing starts at $1.67 in 1,000 unit quantities.

About Semtech

Semtech Corporation is a leading supplier of high-quality analog and mixed-signal semiconductor products.  The company is dedicated to providing customers with proprietary solutions and breakthrough technology in power management, protection, advanced communications, human interface, test & measurement, and wireless connectivity products.  Publicly traded since 1967, Semtech is listed on the NASDAQ National Market under the symbol SMTC.  For more information, contact Semtech Corp. at 200 Flynn Road, Camarillo, CA 93012-8790; phone (805) 498-2111; email to info@semtech.com; or visit its web site at www.semtech.com.