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National Semiconductor Targets Wireless Phone and Digital Consumer Markets with High-Performance Ultra Low Dropout (LDO) Regulator in Micro SMD Package

Nov 21, 2000

November 21, 2000 - National Semiconductor Corporation (NYSE:NSM) today announced a CMOS Low Drop-Out (LDO) regulator designed to improve talk and standby times in GSM, TDMA and CDMA cell phones. With its extremely low dropout voltage, the LP3985 micropower LDO can also increase the operating times in other battery-powered portable equipment like PDAs, PALM devices, digital cameras, digital watches, Bluetooth and GPS modules.  The LP3985 also offers best-in-class signal-to-noise (SNR) performance, which helps mobile phones hold onto calls more effectively.  Housed in a tiny micro SMD package and designed to use small, low-value ceramic capacitors, the LP3985 is the world's smallest LDO solution. 

"Performance and size are extremely critical issues in the dynamic world of wireless and digital consumer designs," said Steven Hunt, director of marketing and applications for National's Portable Power Systems Group.  "National's LP3985 LDO voltage regulators offer low dropout and other performance features that few if any competitors can approach.  The icing on the cake is the innovative package it's wrapped in.  As micro SMD packages are integrated into system designs, they are shortening production cycles, increasing product reliability, and ultimately changing the way products go to market."

At a full load of 150 milliamps, the LP3985 has a typical voltage drop of 60mV between its input and output voltage due to low Rds On characteristics.  Battery life is also prolonged by the IC's low quiescent current of 160 microamps, which drops to one microamp in shutdown mode.  A logic-controlled on/off input allows designers to dynamically manage power management inside their system and with turn-on times of 200 microseconds the LP3985 offers the best solution available for supporting future GSM/GPRS, GSM/EDGE, CDMA and WCDMA mobile standards.

Low SNR (Signal to Noise Ratio) is enhanced by a PSRR (Power Supply Rejection Ratio) of 60dB at 1kHz and 50dB at 10kHz.  Low noise, rated at 30microVrms over 10Hz to 100kHz, also allows the use of a small 1 microfarad output capacitor, which can be either ceramic or high-quality tantalum.  A by-pass capacitor will reduce the output noise still further without slowing down the load transient response.  The five-bump package measures only 0.828mm by 1.387mm with a low profile of 0.85mm.

A variety of standard output voltage options including 2.5V, 2.8V and 3.0V are available to meet the requirements of all wireless and digital consumer designs.  Output voltage accuracy is 2.0% at room temperature and 4.0% over all load, line and temperature conditions.

Price and Availability
The LP3985IBP, in the 5 I/O micro SMD package, is priced at $.56 in quantities of 1,000.  The LP3985IM5, in the SOT23-5 package, is $.50 in quantities of 1,000.  In addition to standard output voltages of 2.5V, 2.8V and 3.0V, other output voltage options from 2.5V to 5V are available.  For more information, visit National's World Wide Web at www.national.com/pf/LP/LP3985.html

About National Semiconductor
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 reported sales of $2.1 billion for its last fiscal year and has about 10,500 employees worldwide.  Additional company and product information is available on the World Wide Web at www.national.com