Data Converters Process RF/MW Signals

Oct. 22, 2009
The latest generation of analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) provide performance in line with communications bandwidths and modulation requirements.

Product life cycles can be short, particularly with certain semiconductors. As any computer owner knows, for example, memory chips continue to grow in density and drop in cost, quickly rendering older memory devices obsolete. Short product life cycles pose daunting challenges for system designers, especially for commercial and military systems that rely on the availability of some devices for a decade or longer. Fortunately, Lansdale Semiconductor (www. has found a solid niche in supplying gone-but-not-forgotten ICs semiconductors that are no longer supported by their original manufacturers but still in demand for commercial and military electronics systems. Lansdale manufactures parts from an impressive list of original manufacturers, a list that includes AMD, Fairchild, Freescale Semiconductor (formerly Motorola SPS), Harris, Intel, National, Philips (formerly Signetics), and Raytheon, often with the original tooling and in the same packaging as the original devices. These form-fit replacement parts offer the same performance levels as the originals to simplify replacement in both commercial and military systems. All Lansdale products are established diminishing source technologies that have been discontinued by the major manufacturers but are still needed to support spares requirements and manufacturing of mature designs. These lines are purchased directly from the original manufacturer. Lansdale is the sole source on over 850 products.

Lansdale was founded in 1964, originally to supply aftermarket germanium transistors from Philco-Ford. Based then in Lansdale, PA, the company relocated to Phoenix, AZ in 1976 after acquiring a product line from Motorola. R. Dale Lillard joined the company from Motorola during that first year of business, shortly thereafter becoming President of Lansdale, and then purchasing the company in 1987. In 1994, Lansdale built a wafer fabrication facility in Tempe, AZ. In February 2000, Lansdale sold the wafer fabrication facility to Primarion, with an agreement for continuing support for foundry services, allowing Lansdale to support older-technology products. Today, Lansdale offers more than 3000 different products. The company is certified and approved by the United States Department of Defense Supply Center, Columbus (DSCC) to manufacture parts for the Qualified Products List (QPL) and is a Qualified Manufacturer (QM) under the MIL-PRF- 38535 Qualified Manufacturing List (QML), as well as an ISO 9000/2000 qualified supplier to the automotive, commercial, industrial, military, and aerospace industries. The QML plan was modified to allow Lansdale to list its parts regardless of whether the die was fabricated by Lansdale or by the original manufacturer.

Lillard explains the model upon which the company is based: "We were still making transistors until about 1986, when I sold the transistor line and we focused on ICs. We were finding that some of the larger IC houses were discontinuing certain products, although some customers still needed these parts. When we would acquire the parts for aftermarket sale, we would use the same tooling and packaging that the original manufacturers used, and that is an important part of our model. When you buy a replacement part, you want it to work exactly the way the original part worked. And we are talking about radar and other critical military systems. We don't take shortcuts in the manufacture of our products."

Although the company has built its reputation for high-quality aftermarket ICs by manufacturing mission-critical, hi-rel military and commercial semiconductors for over 40 years, it has recently become more aggressive in also serving wireless and RF communications markets, providing such functions as phase-locked loops (PLLs), prescalers, frequency synthesizers, transmitters, receivers, transceivers, voltage-controlled oscillators (VCOs), frequencymodulated (FM) subsystems, analogto- digital converters, modems, codecs, and drivers/receivers. For example, the firm recently announced the availability of the MC13135 wireless integrated circuit (IC), an FM receiver originally designed and built by Freescale, and the second generation of a single-chip, dual-conversion receiver IC developed by Motorola. The MC13135 includes a Colpitts oscillator, VCO tuning diode, low-noise first and second mixer and local oscillator ( LO), high gain limiting intermediate-frequency (IF) stage, and received-signal-strength-indication (RSSI) circuitry. It is designed for use with an LC quadrature detector and has an uncommitted operational amplifier (opamp) that can be used either for an RSSI buffer or as a data comparator.

The IC features high gain and stability over a wide operating-voltage range. It can be used for stand-alone very-highfrequency (VHF) receivers or as the lower IF of a triple-conversion system. Applications include cordless telephones, short-range data links, two-way radios, wireless temperature sensors, and scanners. This IC is available in the original product package configurations: PDIP or SOIC 24-pin package. The MC13135 is manufactured using Freescale's original parameters and built as an exact replacement for the original IC.

Lillard notes that about one-half of the company's business is now based on commercial markets, with the strongest growth coming from wireless devices. Customers have a large part in the devices that Lansdale supports, according to Lillard: "We can't do everything. You have to pick the parts you support carefully, based on customer need. Our customers have been faced with having to redesign a system, or have us support an old part that will allow them to stick with the existing design of the system. We first look to see if there is any inventory that we can buy. Redesigning the system itself with a new device is an option, but often expensive. The last option, having us build the exact original part for them, they are willing to pay a generous price for the part because it is a less expensive option that redesigning the system. In a commercial system, there is less of an expense in redesigning the system." Lillard adds that "the technology lifecycle of many ICs is getting very short, so circuit designers are challenged to develop solutions that are based on devices that will still be available for a number of years."

He explains that commercial customers often look to Lansdale for simple solutions: "On the commercial side, we offer a number of building-blocktype technologies. Our products on the wireless side are like those building blocks. These customers are not building high-volume products such as cell phones, but are interested in simplicity. They are designing circuits with fairly simple functions. Motorola buys from us for some of their wireless Internet systems, such as simple amplifiers. They want a simple circuit, and they buy these amplifiers in fairly high volume. They don't want the more complex amplifiers that other suppliers offer, but just want something simple that works in their system." Concerning the newest addition to the product lines, the MC13135 FM receiver, Lillard offers that "it is a very simple part that can be used for any number of applications, such as garage-door openers."

Prior to the MC13135, Lansdale had developed a healthy presence in commercial markets with the acquisition of the ML145170 single-chip CMOS frequency synthesizer originally developed by Freescale. Designed for direct use in MF, HF, and VHF bands, the device is simple to program and draws low operating supply current. It has a patented jam load feature that prevents erroneous data from being loaded into counters and improves lock times. Package types include the 16-pin plastic PDIP, SO, and TSSOP with RoHS-compliant versions also available.

The firm is committed to supporting RoHS compliance by providing its customers with a large choice of leadfree prodcts, even when such product versions were not an option from the original manufacturer. The company supports all products recently transferred from Motorola and Freescale in both lead-free and lead-solder-plated lead finishes, with no additional charge for the lead-free, RoHS-compliant product versions.

For the future, Lillard promises that the Lansdale model will remain consistent: "From the beginning, Lansdale has specialized in aftermarket technology manufacturing and supplies for discontinued semiconductors and ICs. We are dedicated to that goal, assuring our customer base that older discontinued semiconductor, RF, and other IC technology product supplies will continue to be available. As technology advances, Lansdale Semiconductor is also keeping an eye on the future. As product life cycles become shorter, more programs are placed at risk by obsolete and discontinued integrated circuits supplies."

For more information on the company, visit their web site or contact them at Lansdale Semiconductor, Inc., 5245 South 39th Street, Phoenix, AZ 85040- 0123; (602) 438-0123, FAX: (602) 438- 0138, e-mail: [email protected], Internet:

About the Author

Jack Browne | Technical Contributor

Jack Browne, Technical Contributor, has worked in technical publishing for over 30 years. He managed the content and production of three technical journals while at the American Institute of Physics, including Medical Physics and the Journal of Vacuum Science & Technology. He has been a Publisher and Editor for Penton Media, started the firm’s Wireless Symposium & Exhibition trade show in 1993, and currently serves as Technical Contributor for that company's Microwaves & RF magazine. Browne, who holds a BS in Mathematics from City College of New York and BA degrees in English and Philosophy from Fordham University, is a member of the IEEE.

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