National Semiconductor Introduces Industry?s Highest Efficiency Buck/Boost Switched Capacitor Voltage Regulator

With 80% Average Efficiency, New Inductor-less IC Achieves Full Use of Battery Capacity in Cellular Phones, Hand-held Organizers, Digital Cameras and Other Portable Products

March 15, 1999 ? National Semiconductor Corporation® (NYSE:NSM) today announced the first in a new class of high-efficiency switched capacitor voltage regulators designed for dynamic step-up (boost) and step-down (buck) conversions. The LM3352 regulated 200mA DC-DC voltage converter offers portable system architects a high-efficiency alternative to LDO regulators, and enables users to take advantage of the full capacity of Lithium-ion batteries. The LM3352 is also a low-cost alternative to inductive switchers, minus the limitations of inductor height and manufacturing issues.

The new device achieves more than 80% average efficiency while producing a constant 3.3V output voltage over the complete discharge cycle of a Lithium-ion battery pack. The LM3352 produces up to 200mA of output current, the highest available in a regulated switched capacitor DC-DC converter and enough for the primary supply in cellular phones, hand-held organizers and digital cameras.

?The unique fractional gain switching architecture implemented in the LM3352 helps maintain high efficiency at high load currents through an entire Lithium-ion battery pack discharge cycle, even when the cutoff voltage is reduced to new lows,? said Venkatesh Shan, National's power management marketing director. ?With this design, OEMs can significantly increase battery life, while saving design cost and space,? he added.

The LM3352 is the first switched capacitor to use an adaptive digital signal processing control system to optimize conversion efficiency and voltage regulation over a wide range of input voltages and load conditions. It is also the first switched capacitor architecture to use multiple fractional gain modes to provide a regulated output voltage between 1.8V and 4V from an input voltage between 2.5V and 5.5V. Output voltages of 2.5V, 3.0V and 3.3V are offered to match industry standard voltage requirements. Non-standard output options between 1.8V and 4.0V in 100mV increments are also available.

The LM3352 combines switch matrix, voltage reference, shutdown logic and control circuitry in a single 16-pin TSSOP package. Operation at 1MHz allows use of small, low-cost 0.33 microfarad surface-mount capacitors.

Price and Availability The LM3352MTC (TSSOP-16) is priced at $2.75 each in 1000-piece lots and is available now in production quantities.
For more information on the LM3352, visit our website at http://www.national.com/pf/LM/LM3352.html, or contact National?s Customer Response Group at 1-800-272-9959.

National Semiconductor provides system-on-a-chip solutions for the information age. Combining real-world analog and state-of the-art digital technology, the company's chips lead many sectors of the personal computer, communications, and consumer markets. With headquarters in Santa Clara, California, National has annual sales of approximately $2.5 billion and 11,500 employees worldwide. Additional company and product information is available on the World Wide Web at www.national.com.