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Amplifiers

Networks Business Unit Looks to WiMAX

November 12, 2007
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Brian Balut joined Sawtek in October 1994 as Sales Manager. He was promoted to Director of Sales and Marketing in November 1996 and to Vice President Sales and Marketing in September 1998. He assumed overall corporate responsibility for this function in July 2002.

Balut joined TriQuint as a result of TriQuint's merger with Sawtek and was promoted to Vice President, Sales and Marketing of TriQuint. He held this position from 2002 to May 2004 at which time he was promoted to Vice President/General Manager of TriQuint Florida. In 2006, after reorganizing the Florida and Oregon locations to a market-based focus, Balut became Vice President of the newly established Networks Business Unit. From 1987 to 1994, he held various positions in sales, marketing and engineering with REMEC, a manufacturer of electronic components. Balut received his BS degree in Electrical Engineering from the Massachusetts Institute of Technology and his MBA degree from Rollins College.

MWJ: I noticed a 2005 press release announcing that TriQuint had become a supporting member of the WiMAX Forum™. How has membership in the WiMAX Forum benefited TriQuint?

BB: One of the value propositions of the WiMAX Forum is the “ecosystem” that it engenders. This ensures that all the stakeholders have a say in development of the technology, as well as a hand in ensuring its success. A direct benefit for TriQuint is seen in the way the Forum helps a company understand the lay of the land. We can better understand the requirements of the market by speaking with – and working with – our partners, the chipset suppliers, as well as our common customers, equipment vendors, as well as their customers: the carriers. The Forum also provides an opportunity to gain a better appreciation for market timing and where we can add the most value. Forum participation gives TriQuint and similar suppliers the opportunity to showcase new and emerging technologies. By engaging with chipset suppliers, equipment vendors and carriers at early developmental stages we use our technology and expertise to lower their system costs and improve system performance.

MWJ: Is WiMAX the main focus of the TriQuint Networks Business Unit?

BB: TriQuint’s main markets include handsets, networks, military and commercial foundry. For networks applications, TriQuint is focused on connectivity: delivering voice, data and video to the user. At TriQuint the concept of ‘networks’ products embraces a healthy mix of revenue from RF components and integrated modules based on GaAs, SAW and BAW technology for base station, point-to-point radio, WLAN, satellite ground terminal, cable and optical applications. We also work with anything that touches on the many flavors of broadband communications beyond WLAN (including the pending WLAN/WMAN convergence), such as personal navigation devices (GPS) and Bluetooth. TriQuint recently released our first Product Selection Guide, which contains nearly 500 products supporting the above applications. The guide is another means we use to make products more accessible through all our various sales channels.

MWJ: Could you provide us with an overview of your WiMAX portfolio?

BB: TriQuint was the first SAW vendor to commit to WiMAX. We have the widest portfolio of IF SAW filters for the emerging market. TriQuint is also developing a family of wideband, flexible PAs for client-side applications to be released over the next few months. These devices are built around the idea of simplifying the complexities of WiMAX profiles now in release. This new PA line will make engineers’ lives easier by ensuring excellent performance over all the key WiMAX bands in the certified 2.5 and 3.5 GHz bands. At the same time they will allow for multiple bias conditions for differing applications. We also offer several discrete HPAs up to 10 W for WiMAX base transceiver station (BTS) applications. Finally, there are higher power products in our roadmap.

MWJ: I notice that certain SAW devices in your product line are specified to work with specific chipsets from vendors such as SiGe Semiconductor, TI, SMI and Beceem. What differentiates these components from each other?

BB: TriQuint is proud of its work to help streamline the use of IF (intermediate frequency) in the industry. For WiMAX to succeed, all parties must work together to standardize as much as possible – not just the air interface, but a portion of the hardware design as well. By streamlining the intermediate frequencies used in WiMAX base stations and consumer devices, economies of scale are realized with the reduction in the number of unique SAW filters developed and sold. In our role as the leading SAW filter provider to the market, we have successfully worked with the various chipset companies you’ve mentioned to ensure that they work towards the same IFs in their designs. Even so, each of the chipset designers has a unique value proposition to offer the market and each RFIC should be evaluated by individual equipment vendors with their specific requirements and specifications in mind.

MWJ: Does the request to work with specific chipsets come from end-users or the chip set manufacturer?

BB: Various chipset manufacturers develop products to comply with WiMAX standards. The decision on which chipset manufacturers to support is a very difficult one to make in the early stages of a new application such as WiMAX. TriQuint maintains close contact with as many of the chipset suppliers and equipment manufacturers as possible to understand which solutions are likely to be the most successful in the market. We then align our product portfolio with these solutions. We evaluate each opportunity on its merit.

MWJ: How significant is the addition of SAW-based IF filters to the TriQuint portfolio of PAs, switches and other products from a business perspective and engineering perspective?

BB: TriQuint has a unique position as the only company combining filter technologies such as SAW and BAW, and active component GaAs technologies under one roof. This enables us to offer a complete portfolio of RF products without stacked margins. RF front-end products are often described as the “unintegratables” because they can’t effectively be designed into silicon. As a result, we work closely to align with partners’ integrated silicon-based transceivers and basebands. TriQuint typically refers to this as our “technology wall” strategy. The fact that we are exclusively an RF supplier makes us valuable to our customer base and our chipset partners because we understand and offer focused solutions in an area that they typically have little or no expertise. We don’t design transceivers. We instead concentrate on perfecting products on our side of the ‘wall’. This approach frees our partners to concentrate on their own areas of expertise, safe in the knowledge that our products are fully optimized to theirs.

MWJ: To cover multiple band classes and achieve economy of scale, RF front-end modules will undoubtedly be complex. Is that the general trade-off - complexity for broader (more general) usage? I assume reducing BoM will be a big concern for handset manufacturers. Is this correct? Will there be more emphasis on advanced package design, off-chip design and IC integration from TriQuint?

BB: We have seen integration of the RF front end in multiple markets as they grow to very large volumes: handsets, WLAN, GPS, etc. As such, should WiMAX be as successful as projected, we anticipate that the market will demand similar integration. Inherently, active devices such as power amplifiers, low noise amplifiers and switches operate over a range of frequencies while filters are typically frequency specific. With its RF technologies and focus, TriQuint is uniquely positioned to realize broadband products and to integrate these functions either at die or module level, depending on the application. We work to minimize our customers’ total BOM. RF front-end modules are inherently complex and will become more so as client side devices are equipped with multiple wireless standards. But modules can be simplified by making creative design choices. As an example, TriQuint has chosen a common device technology platform (E/D pHEMT) for both WLAN and WiMAX client-side applications. There is a lot of commonality in 802.11g and 2.5 GHz WiMAX Tx requirements that opens up the possibility of using a single PA/switch for both applications. I believe TriQuint’s recent acquisition of Peak Devices and that company’s expertise with broadband applications is another example of how we are working to achieve greater performance without the encumbrance of design trade-offs.

MWJ: Is TriQuint in a position to influence particular aspects of a standards profile through Forum membership or are the technical specifications handed down from above with little input from the device providers?

BB: As a member of the Forum, we have a voice in determining the specifications. We advise system designers what is technically feasible at the component level. This helps them make decisions in dealing with the inevitable trade-offs between designs. TriQuint’s technology is an important enabler to the success of the WiMAX standard. For example: the output power of the PA in a WiMAX user device has a direct effect on link budgets and, subsequently, on the number of base stations required to cover a given area. Greater efficiency and the ensuing increase in power can mean a decrease in base stations, which results in a more attractive business case for the carrier. Meanwhile, delivering that power efficiently will also reduce heat dissipation and increase mobile device battery life. These are key elements for both consumer uptake and service providers’ revenue models.

MWJ: Is the WiMAX standard nailed down enough for engineering groups to know what they are designing or is it somewhat of a moving target?

BB: The Fixed WiMAX standard is complete and several profiles are released with multiple equipment suppliers certified. While the Mobile WiMAX standard is not released, it is certainly close enough to being finalized that it has not hamstrung systems or components designers.

MWJ: According to the TriQuint article in this month’s MWJ WiMAX supplement, parts are defined by RF band, channel size and duplex mode. How does a specification such as duplex mode influence the device requirements?

BB: A radio using Time-Division Duplexing uses the same RF antenna path – and frequency channel – for both transmit and receive. This design requires a switch at the antenna that constantly moves back and forth between transmit and receive chains. A Frequency-Division Duplexing radio uses two separate antenna paths and two separate frequency bands (or sub-bands); there is no need for a switch. Having different antenna configurations leads to other basic differences in RF front-end design. FDD systems require two spectrally separated bands that in turn require additional RF system planning. Within TDD systems, switching speed and power stability across the transmit pulse and off-state noise power are very important PA performance characteristics to designers. WiMAX is predominantly a TDD system at this point in its deployment.

MWJ: Wouldn’t a part that addressed a larger channel size also address a smaller one? Are there any trade-offs to achieving the greater channel bandwidth?

BB: There are trade-offs when developing wideband PAs. Generically speaking, an amplifier can be designed to work over a wide band, but may be optimized for performance over a narrow subset of that band. The ‘trade-offs’ that are the most common when covering a wider spectrum include return loss, gain flatness and efficiency. The world’s WiMAX bands fall into 2.3 to 2.7 GHz and 3.3 to 3.8 GHz ranges, typically referred to as the 2.5 and 3.5 GHz bands. Contemporary technology would leave a PA attempting to cover both these bands (from 2.3 all the way up to 3.8 GHz) sub-optimized for return loss, gain and efficiency compared to a two-device solution. The challenge is to determine the frequency coverage needed while optimizing performance for narrower sub-set bands. TriQuint has taken steps to solve this problem in the near term by designing two PAs into a single small package for both the 2.5 and 3.5 GHz bands. However, our Peak Devices acquisition brings us IP that will allow for wider bandwidth amplifiers with fewer trade-offs. Using that advantage a designer may be able to develop an amplifier covering 2.3 to 3.8 GHz that satisfies sub-optimization needs while meeting the other critical requirements. The advantage is clear since a wideband device brings value in design simplification, BOM count reductions and multi-platform part reusability. The commonalities found between low band WiMAX and 802.11g PA designs mean there can be additional leverage of this device class across different applications.

MWJ: Are there significant differences between parts for WiMAX and those targeting WiBro?

BB: The two standards are converging, so the simple answer is ‘no.’ However, if one digs deeper there are a couple of esoteric discrepancies. WiBro – which is used exclusively in South Korea – specifies an 8.75 MHz channel bandwidth, while the rest of the WiMAX world allows 3.5, 7 and 10 MHz channels, as well as 20 MHz channels in the 5.8 GHz band. This difference has already been addressed as 8.75 MHz channels have been included in the Forum’s set of profiles for Mobile WiMAX. Another distinction between WiMAX and WiBro is since the latter was developed specifically for the Korean market it uses spectrum between 2.3 and 2.4 GHz made available by the Korean government. Since our client-side PAs are designed to cover the 2.3 to 2.7 GHz band, they will work equally well for 2.5 GHz Mobile WiMAX and WiBro. One of the key challenges the WiMAX Forum has undertaken is working with governmental regulatory agencies to harmonize spectrum available for WiMAX services. TriQuint brings value to this effort not through political means, but through development of the wideband PAs mentioned earlier. When one PA can address multiple bands in multiple countries, design is simpler and BOMs are cheaper. The advent of highly efficient wideband PAs could encourage more multi-country carriers to roll-out WiMAX coverage. If radio designs are simpler – less complex, and one handset could be used across more international borders, then the entire WiMAX business proposition becomes more attractive.

MWJ: What are the leading concerns in the industry right now – performance, cost, size, etc.?

BB: The operator’s business case is always the leading concern for an emerging market – especially one that requires a capital-intensive build-out at the front end. The markets (both financial markets and consumer markets) are generally convinced that personal broadband – the concept of “any content, any where, on any device, at any time” – has a latent demand. The question is whether WiMAX can meet that demand at a price point that makes sense for end users. One of the other serious barriers to worldwide deployment of mobile WiMAX is spectrum allocation. The WiMAX Forum is working very hard with regulatory agencies to resolve this issue. On the performance side, the trade-off between client-side transmit power required to achieve acceptable range and data rate vs. battery life continues to be worked.

MWJ: Are most CPE and base station customers looking for off-the-shelf parts or are custom components more the norm?

BB: The concept of WiMAX being viable as a global wireless standard is based on the assumption of access to interchangeable radio hardware. The specifications for components are fairly uniform so that parts developed as ‘custom’ or ‘semi-custom’ will be suitable for off-the-shelf standard product sales. In the early days, there were no off-the-shelf parts – the ‘shelves’ themselves weren’t even built yet. As the market has matured and as the WiMAX profiles have been formalized, the industry has realized that the value of standardization drives down to the component level. TriQuint has developed application specific standard products (ASSPs) such as filters, switches and power amplifiers compliant with these profiles to enable multiple equipment manufacturers and service providers to compete in this space.

MWJ: What is the typical product life cycle these days? Do certain products have especially short or long life cycles?

BB: The typical product life cycle is more a function of whether the product is used in some form of customer premise equipment (client-side) versus network infrastructure. Any CPE device typically has a life cycle of 1-3 years while network infrastructure is significantly longer.

MWJ: Do you think we are entering the peak in WiMAX-related R&D engineering in terms of money spent (proceeding deployment) or is the peak still a few years out?

BB: If we equate WiMAX to other frequency specific high growth markets such as cellular and WLAN, the R&D money spent up-front is only a small percentage of the R&D needed to continue to drive product cost down and improve product performance for continued adoption and market growth.

MWJ: I assume your designers and application engineers are working closely with specific partners to integrate your devices into their platform? If so, could you describe how you have been working together?

BB: Our relationships with our chipset partners can be described as “active.” Once we’ve mutually determined that the relationship makes sense, there is a constant flow of architecture, product specs, comments, simulations and prototype hardware between us. Starting with a “dream” spec and ending with parts that meet all of the system requirements, we ensure that our partners – and in the end, our common customers – have the best parts for the WiMAX applications they are addressing.

MWJ: In the article, the author mentions that early WiMAX-based handsets had deficient battery life and tended to heat up during extended use, due to the power amplifiers. What is it about the WiMAX standard operating conditions that make the handset power amplifier design especially challenging?

BB: While operating conditions play a part, the business case is the real driver. WiMAX uses 2.5 and 3.5 GHz bands, which necessarily have shorter propagation characteristics than lower frequencies. This will reduce cell size, which increases the number of base stations, which in turn increases cost. A powerful PA in the handset will contribute to overcoming that, but battery life and heat dissipation concerns require that the PA not only be powerful, but also efficient. This is the challenge for the PA designer: develop a PA that enables lower-cost networks (fewer base stations) and high-performance consumer devices (long battery life).

MWJ: It’s pretty clear how important PA development will be to the success of WiMAX, particularly with regards to efficiency. What are some of the avenues TriQuint is exploring to meet this challenge?

BB: TriQuint is aggressively working on technologies and PA products both for low power and low supply voltage WiMAX CPE applications as well as high power, high linearity infrastructure applications. Technologies such as our E/D pHEMT enable TriQuint to integrate switch and high efficiency PA functions for low cost CPE applications. TriQuint is also investing in DC to DC converters to improve efficiency of CPE-based power amplifiers. In addition, TriQuint has been developing a suite of high efficiency linear gallium arsenide technologies such as high voltage HBT, high voltage pHEMT and gallium nitride (GaN) for WiMAX infrastructure, as well as 3G and 4G cellular base station and military applications.

MWJ: Do you see any specific areas where TriQuint needs to invest in specific technologies in order to compete better?

BB: In line with our RF-focused strategy, TriQuint continues to invest in RF technologies to improve the system performance or lower the system cost of our customers’ applications. We first assembled the initial building blocks of filtering technologies such as BAW and SAW combined with our early HBT and pHEMT GaAs technologies for amplifiers and switches. We have added technologies such as E/D pHEMT and multiple-metal interconnect that enable die level integration in addition to module integration. We continue to invest in packaging and test for high frequency products as well as flip-chip technology for low cost. Finally, through our recent acquisition of Peak Devices, we have added a broadband capability to maximize our high voltage and high power technology performance.

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