NATIONAL SEMICONDUCTOR ANNOUNCES FIRST DIGITALLY CONTROLLED 600MHZ GAIN TRIM AMPLIFIER (GTA) -- IDEAL FOR IF APPLICATIONS

CLC5506 GTA Achieves Performance Levels Four Times Better than Competitive Solutions

July 6, 1999 -- National Semiconductor Corporation® today announced its CLC5506, the industry?s first high resolution gain trim amplifier. National?s innovative GTA integrates key intermediate frequency (IF) functions into a digitally programmable amplifier that greatly enhances a system?s dynamic range, and delivers a level of performance unmatched in current monolithic solutions. The CLC5506 is the first digitally programmable integrated circuit to achieve a fine 0.25dB step resolution, making its resolution four times better than any other digitally controlled variable gain amplifier (DVGA). With an extremely low noise figure of 4.8dB at 18dB gain and 600MHz bandwidth, the CLC5506 is the only integrated solution that can fully support the stringent requirements of a wide variety of IF applications such as cellular basestations, wireless local loops, radar and cable modems.

"With today?s announcement, National is the first to launch an integrated solution that provides an essential component for optimizing dynamic range in IF signal chains. The GTA greatly simplifies system design and production of IF front ends by eliminating complex and costly discrete IF low noise amplifiers, digitally programmable step attenuators and support circuitry," said Jeff Hooker, product marketing manager for National?s high speed amplifier products. "The GTA is excellent for all IF applications requiring bandwidths as high as 600MHz, and provides 10dB to 26dB of gain, selectable in 0.25dB steps."

Integration Equals Cost Benefits
The CLC5506 integrates a low noise amplifier (LNA), a 6-bit programmable attenuator and a MicroWire™ interface into a single monolithic solution. This integration saves valuable board space and offers significant cost savings by replacing discrete solutions that can cost as much as $15, depending on the complexity and level of performance required. The CLC5506 also eliminates the need for a separate -5V power supply that some systems require for biasing FET switches necessary to drive step attenuators.

Comprehensive Feature Set for IF Applications
The CLC5506 is ideal for applications that require factory trimming at the IF stage to optimize dynamic range in high-end systems. The digitally selectable 0.25dB step size allows for very precise trimming that corrects for component-to-component manufacturing losses and spec variations (caused by mixers, SAW filters and other discrete components) that limit dynamic range performance.

The programmable gain feature also allows system designers to maximize performance in their IF applications by correcting for changes in component gains and losses during system temperature fluctuations that can further degrade dynamic performance. This is critical for systems that are exposed to daily and seasonal temperature fluctuations such as outdoor cellular base stations, rooftop wireless local loops and radar.

In addition, the CLC5506 has been optimized for receivers requiring excellent low noise performance. It minimizes front-end noise by offering a low noise figure of 4.8dB at 18dB gain, and differentially coupled input and output architecture. This input output architecture also facilitates easy interfacing to the SAW filters? matching networks and allows the GTA to drive high-speed ADCs directly.

The CLC5506 operates off a single 5V supply and only consumes 75mA of current. An additional shutdown feature further drops supply current to only 35m A when the GTA is placed in standby mode. The CLC5506 is specified to operate in systems with an ambient temperature range of -40°C to +85°C.

Pricing and Availability
The CLC5506 is currently available in a 14 Pin Plastic SOIC and is priced at $4.95 each in quantities of 1,000. Populated evaluation boards are priced at $60 each. For more information on the CLC5506 visit http://www.national.com/pf/LM/CLC5506.html

About National
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 has annual sales of $2 billion and 11,500 employees worldwide. Additional company and product information is available on the World Wide Web at www.national.com