NATIONAL SEMICONDUCTOR INTRODUCES INDUSTRY'S FIRST VERY HIGH PRECISION, LOW NOISE, SUB-BANDGAP (1.024V) SERIES REFERENCE

The LM4140 Offers 1.024V, 0.1% Accuracy and 3ppm/?C Tempco in an SO-8 Package

September 6, 2000 - National Semiconductor Corporation (NYSE:NSM) today announced the industry's first sub-bandgap series voltage reference. The LM4140, with a voltage reference of 1.024V, is ideal for battery-powered devices requiring ultra-high precision and low noise, such as instrumentation and test equipment. Traditional silicon bandgap voltage is 1.2V and is based on the intrinsic property of the material to conduct electrons. In-factory post-assembly trimming and EEPROM-based storage of calibration constants enable 0.1% accuracy and a 3ppm/?C tempco in National's LM4140 - all in an SO-8 package.

"Traditionally, high-precision references use buried Zener technology, necessitating higher quiescent currents and higher input voltages," said Venkatesh Shan, National's director of marketing for power management products. "A sub-bandgap voltage reference could only be achieved with an adjustable voltage reference and an external voltage divider and often a buffer - a solution that came at the expense of high precision and requiring bulky external components. Now, not only does the LM4140 offer high accuracy and low temperature coefficient in a small package, but it can achieve voltages less than the bandgap reference of 1.2V and promises references down to 0.5V."

For space-critical applications, the LM4140 is available in the 8-lead surface mount SO package. In addition to offering very high initial accuracy and low tempco, the LM4140 also features very low noise of 2.2microV_pp (0.1Hz to 10Hz) and a low 1ppm/mA load regulation. Long-term stability measures an industry low of 60ppm over 1000 hours and thermal hysteresis of only 20ppm.

The quiescent current of the LM4140 is typically 230microA, with shutoff current less than one microamp. The LM4140 also has an enable pin to prolong battery life when the reference is not operating. Because it is a series reference, the LM4140 can also be used as a low current, high precision LDO. The dropout voltage is as low as 20mV @ 8mA and the device can source up to 8mA.

The LM4140 voltage reference comes in five reference-voltage options: 1.024V, 1.25V, 2.048V, 2.5V and 4.096V and is specified over 0?C to +70?C temperature range. Custom voltages are also available upon request. The LM4140 has 0.1% initial accuracy and comes in three grades for greater application flexibility: A-grade: 3ppm/?C tempco; B-grade: 6ppm/?C tempco and C-grade: 10ppm/?C tempco.

Pricing and Availability
Available now, the A-grade LM4140 is priced at $4.40 each, the B-Grade at $2.85 and the C-Grade LM4140 is $2.40 all in 1000-unit quantities. For more information on these products, visit National's World Wide Web site at http://www.national.com/pf/LM4140.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