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National Semiconductor Introduces New Family of High-Current LDOs for Modem, Set-Top Box and PC Applications

New Family of Dual-Rail CMOS LDOs Enables Efficient Power Conversion from 2.5 V and 1.8 V Rails

Sep 23, 2003

September 23, 2003 - Expanding its portfolio of high-current low dropout (LDO) regulators, National Semiconductor Corporation (NYSE: NSM) today introduced a new family of CMOS dual input rail LDO regulators targeting low voltage, high-current applications in cable modems, desktop PCs and set-top boxes.  Tailored for powering the latest processor, digital ASIC and DSP cores, the new family’s dual input architecture offers high performance linear regulation while providing significant power savings and reduced external component costs to design engineers.

“The LP389x family uses a separate input to power the control circuitry; the power input may be fed independently from the high current supply facilitating conversion from a 2.5 V or a 1.8 V input, ” said Paul Greenland, marketing director of National Semiconductor’s power management group.  “By virtue of the CMOS design, only 3 mA of quiescent current is drawn by the control circuit under all conditions.  In contrast, bipolar equivalents demand in excess of 100 mA as the regulator approaches dropout.”

The LP389x family is comprised of the LP3893, LP3892 and LP3891.  The dropout voltage for the family is typically at 270 mV, 140 mV and 100 mV at 3 A, 1.5 A and 0.8 A and a maximum of 1 V, 500 mV and 400 mV over temperature. 

Other key features of the LP389x family include ON/OFF control, output voltage accuracy of plus and minus 3 percent over all conditions, low output capacitor requirements (10 mF), and over-temperature and over-current protection. The family’s unique circuit approach enables delivery of custom voltages in 50 mV increments in the range of 1.2 V to 1.8 V within four weeks of receipt of order. 

Shipping now, the LP389x family of dual rail LDOs is offered in either a TO220-5 or a TO263-5 package.  In quantities of 1,000 units, the LP3893 is priced at $1.75 each; the LP3892 is at $1.40 each and the LP3891 at $1.20 each.

About National Semiconductor
National Semiconductor is the premier analog company driving the information age. Combining real-world analog and state-of-the-art digital technology, the company is focused on analog-based semiconductor products, which include stand-alone devices and subsystems in the areas of power management, imaging, display drivers, audio, amplifiers and data conversion. The company targets key markets such as wireless, displays, PCs, networks and a broad range of portable applications. With headquarters in Santa Clara, California, National reported sales of $1.67 billion for its most recent fiscal year. Additional company and product information is available on the World Wide Web at www.national.com