NATIONAL SEMICONDUCTOR ENHANCES 12-BIT A/D CONVERTER FOR NEXT-GENERATION CELLULAR BASE STATION RECEIVERS

New IC Simplifies Design of Expanding IF-Sampling Receiver Solutions

October 11, 1999- National Semiconductor Corporation (NYSE:NSM) today announced a 12-bit A/D converter that simplifies the design of IF-sampled wireless base station receivers, the CLC5957. Operating at a guaranteed sample rate of 70MSPS, this latest member of the CLC595X family of high-performance converter products offers industry-leading performance with ease of design enhancements targeted for those applications.

"For wireless base stations, customers want a high-resolution ADC that simplifies the receiver chain. To meet that goal, designers can use the CLC5957 to help eliminate the entire second and third IF stages used in conventional baseband receivers. This reduces design complexity, part count, space and cost by eliminating a number of analog filter, mixer and amplifier stages," said Kurt Rentel, marketing manager for National's wireless base station products. "The CLC5957 provides superior receiver sensitivity in EDGE, GSM, CDMA, TDMA and the 3G WCDMA standards, with such features as a 74dB spurious free dynamic range (SFDR) and 67dB signal-to-noise ratio (SNR) at 5MHz and 65dB SFDR and 66dB SNR at 250MHz."

The wide band track-and-hold of theCLC5957 allows sampling of signals up to 300MHz. This capability simplifies receiver design by directly converting IF frequencies and helping to eliminate expensive amplifiers, analog filters and mixers.

For demanding designs, the CLC5957 features a proprietary 12-bit multi-stage quantizer, a low distortion track-and-hold with 0-300MHz input bandwidth, differential analog inputs, low jitter differential universal clock inputs, and a bandgap voltage reference.

Ease of Design
The differential analog inputs of theCLC5957 are designed to provide excellent common-mode-rejection, whereas the differential universal clock inputs permit the use of balanced clock signals to minimize clock jitter. The CLC5957 includes a data-valid signal and TTL/CMOS-compatible programmable 3.3V or 2.5V output logic for easier system design. The CLC5957 also enhances non-wireless applications such as infrared and CCD imaging, electro-optics, instrumentation, medical imaging and high-definition video.

Housed in a 48-pin TSSOP package, the CLC5957 presents an extremely small footprint for applications where space is critical. The CLC5957 may be operated with a single +5V power supply and functions over the industrial temperature range of -40 to +85 degrees C. It consumes only 640mW of power. National also offers a CLC5957 evaluation board that facilitates quick bench trials and simplifies final system design.

Pricing and Availability
Available now, the CLC5957MTD is priced at $19.90 each in 1K quantities. The order number for a fully-loaded evaluation board is CLC5957PCASM. For more information on the CLC5957, visit National's web site at www.national.com/appinfo/wbp, or contact National's Customer Response Group at 1-800-272-9959.

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 billion for its last fiscal year and currently has about 11,000 employees worldwide. Additional company and product information is available on the World Wide Web at www.national.com.