NATIONAL SEMICONDUCTOR'S NEW LOW DROPOUT (LDO) REGULATOR EXTENDS BATTERY LIFE AND LOWERS NOISE IN CELLULAR PHONES AND OTHER BATTERY-POWERED EQUIPMENT

IC Optimized for Stable Operation with Ceramic Output Capacitors

July 21, 1998 - National Semiconductor Corporation? today introduced a micropower low-dropout (LDO) regulator that reduces high-frequency noise and increases battery efficiency in cellular phones and other portable equipment by taking advantage of the low ESR (equivalent series resistance) of ceramic output capacitors. The LP2985 is designed to assure stable operation across the entire range of operating temperature and output current when used with small, low-cost ceramic output capacitors having ESR as low as 5 milliohms.

"The development of the LP2985 gives National's customers the system price and performance benefits of low ESR ceramic output capacitors in their regulator designs," said Venkatesh Shan, National's power management marketing director.

The addition of a small bypass capacitor reduces output noise to 30?V (typ), nearly one-fifth the level of a typical micropower regulator. This low noise output simplifies overall design and improves the performance of noise-sensitive applications such as RF circuitry in cordless phones, cellular phones and pagers. The low-noise operation of the LP2985 is also highly desirable in audio applications, sensor supplies, and high-end data acquisition systems.

Minimal dropout voltages - typically 280mV at 150mA output current - help extend useful battery life. A power-saving sleep mode reduces quiescent current to less than 1 microamp (max) over temperature. With guaranteed 150mA output current and 350mA transient peak output, the LP2985 is housed in a space-saving TinyPak™ SOT23 package that occupies less than one-third the printed circuit board space of a standard SO-8 package. The combination of reduced package size and low power consumption make the LP2985 ideal for a variety of battery-powered systems, including PDAs, portable PCs, camcorders, cameras and SMPS (switched mode power supply) post regulators.

Price and Availability
The LP2985 is available in 3.0, 3.3 and 5.0V versions. Special voltage options are also available on request. The A-grade LP2985AIM5, with an output voltage accuracy level of 1.0%, is priced at $0.73 each, when purchased in quantities of 1000. A standard-grade LP2985IM5, with 1.5% guaranteed voltage accuracy, is priced at $0.63 each in 1,000s.

For more information on the LP2985 visit our website at http://www.national.com/pf/LP/LP2985.html or call National Semiconductor's Customer Response Group at 1-800-272-9959.

National Semiconductor Corporation produces system-on-a-chip silicon solutions for the information highway, based on its leadership in analog and mixed signal technologies. National is headquartered in Santa Clara, California, and focuses on the communications, personal systems and consumer markets. National has annual sales of approximately $2.5 billion and 13,000 employees worldwide. Additional company and product information is available on the World Wide Web at www.national.com.

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