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New 3 A Dual-Rail Linear Regulator from National Semiconductor Enables Efficient Power Conversion from 1.8 V Input for Set-top Box and Server Applications

Dec 11, 2002

Dec. 11, 2002 - Continuing its innovations in power management technology, National Semiconductor (NYSE: NSM) today introduced the world’s first CMOS dual input low dropout (LDO) voltage regulator.  The new product offers the industry’s lowest dropout and makes efficient linear conversion from low input voltages possible.  Optimized for low-voltage, high current applications in set-top boxes, servers and desktop PCs, the new high-current linear regulator consumes only 3 mA of quiescent current without compromising transient response. 

The LP3883 uses a separate input to power the control circuitry.  The power input may be fed independently from the high current supply facilitating conversion from input rails of less than 2.5 V.  This feature combined with the device’s guaranteed maximum dropout of less than 450 mV, allows efficient linear conversion from a 2.5 V or 1.8 V rail.  With the LP3883, designers now have a linear alternative to complex, noisy switching regulators when generating output voltages down to 1.2 V.

“National’s LP3883 LDO is the latest in a long line of industry firsts, allowing designers to create 1.2 V, 3 A rails without recourse to a switching regulator,” said Paul Greenland, Marketing Director of National Semiconductor’s Power Management Group.  “With CMOS dual input architecture, the LP3883 consumes only 3 mA of quiescent current under all conditions.  Compare this to the quiescent current of bipolar alternative which increases to over 100 mA as the regulator approaches dropout.  Furthermore, bipolar regulators place restrictions on the quality and quantity of filter capacitors for stable operation.”

The LP3883’s unique circuit approach enables delivery of custom voltages in 50 mV increments in the range of 1.25V to 1.8V within four weeks.  The LP3883 has an output voltage accuracy of ?3 percent over line, load and temperature variations and features on/off control, over-temperature and over-current protection.

Availability, Pricing and Packaging
National Semiconductor’s LP3883 LDO regulator with 1.2 V, 1.5 V and 1.8 V output voltages is available for shipment in 5-lead TO-220 and TO-263 packages, it is priced at $2.68 each in 1,000 quantities. 

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 the fast growing markets for wireless handsets; displays; information infrastructure, and information appliances. With headquarters in Santa Clara, California, National reported sales of $1.5 billion for its most recent fiscal year and has about 10,000 employees worldwide. Additional company and product information is available on the World Wide Web at www.national.com