Analogue market continues to grow as demand surges

Those companies often have portfolios of hundreds, maybe even thousands, of parts. You might think that designers could find just the device they needed from what's out there and that anyone looking to enter the market would be wasting their time and money. But it's not the case. Touchstone Semiconductor is an example. Launched three years ago, the company is developing its presence in the market through a combination of its own devices and second source versions of other company's products. Dr Jeroen Fonderie, the company's vp of engineering, said the focus is on high performance standard analogue parts. "We're not looking at the big SoCs that other companies are targeting. We think there's a hole in the market and the opportunity for us to be innovative." In some respects, Touchstone is a throwback to the earlier days of analogue. Dr Fonderie, who spent 12 years at Maxim, latterly as executive director of design engineering, said Touchstone founder Brett Fox wanted to start a company that would be just like Maxim and Linear Technology were in their early days. He sees the opportunity being created by the larger companies focusing on larger customers. "There's a big part of the market which isn't their main focus. But it is for us and we see opportunities." Touchstone is currently pursuing a market strategy which involves designing its own products as well as providing second source versions of devices that are currently available only from one company. "We now have more than 60 parts on the market," said Dr Fonderie, "and we're working on a lot more. Our focus is on the broad market; while we have expertise in many areas, there's only so much you can do at one time." One of the drivers behind its product development strategy is the need for high power efficiency, whether that's low voltage, low current or both. "It's an important parameter for any component that will be used in hand held devices, whether intended for the consumer or industrial sectors. But, because we are making standard products, they will be used by many customers." The second source strategy is important to Touchstone. "When we started the company," Dr Fonderie noted, "we needed to be self sustaining. Bringing out second source products is a tried and tested approach used by many companies. If you come out with second source parts, they don't need to go through a long design cycle, although they do need to go through a qualification phase. "We pick second source products carefully," he continued. "We're not going after everything; we have to focus on products that are currently single sourced, current and successful. However, we are not competing on price." Recently, Touchstone launched 13 analogue comparators that are identical electrically and in format to equivalent devices from Maxim. But it says all 13 are lower cost. At the moment, the Touchstone portfolio is split about 50:50 between original and second source devices. "But we have a lot of proprietary designs in the pipeline," Dr Fonderie asserted. "We will always be looking for good second source opportunities, but we do have a good product design and differentiation team." One of the recent proprietary introductions from Touchstone is the TS7001; a twin channel 12bit a/d converter designed as a competitor to Analog Devices' AD7887 – which Touchstone also second sources. The device is not only 50% faster than the AD7887, it also has a 50% smaller footprint and costs less. The TS7001, supplied in an msop8 package, integrates a 10MHz track and hold, a high speed three wire interface and an internal 2.5V reference accurate to within ±0.5%. Operating from a supply ranging from 2.7V to 3.6V, the device consumes 3mW when converting at 187.5ksample/s. "It's an example of our approach where we develop parts with tighter specs," Dr Fonderie noted. "In this case, we've improved the sample rate by 50% to 187.5ksample/s." The focus is on analogue building blocks, including amplifiers, comparators and a/d converters. "We're working on similar components," Dr Fonderie continued, "targeting all of the signal chain, including voltage references, power components, interfaces and demuxes. Everything we're working on is targeting low power." And Dr Fonderie said Touchstone has no 'secret sauce'. "We have skilled and experienced designers who continue to come up with good ways to do things. And when we develop innovative ideas, we'll file for patents." Design expertise is an important element for Touchstone. "Our designers have an average of 20 years analogue design experience," he continued. "It's a skill which needs many years of practical experience before designers get good at it." One thing which has enabled Touchstone to develop power efficient products is its relationship with TSMC. "We haven't developed our own process technology," Dr Fonderie pointed out. "We use foundries like many other companies. But what sets us apart from other companies using foundries is our design team and its ability to come up with differentiated products."












By using TSMC, Touchstone has access to leading edge analogue technology, which it can apply to both its proprietary and second source designs. "Some years ago," Dr Fonderie recalled, "when an analogue company engaged with a foundry, it ended up talking about digital processes which could be used for analogue products. But the technology to which you had access was nothing like that being applied by companies, such as Maxim and Linear, which had their own fabs. Using a foundry then turned out to be a competitive disadvantage. "However, over the last few years, foundries have discovered that analogue is a good market to be in and have made significant development efforts. Today, analogue foundry processes are available at 0.1µm and they are very competitive." No matter where analogue components are manufactured, those developing the products are looking at a number of parameters. Dr Fonderie explained: "Modern analogue processes have precision components. You need high precision or your product won't work in the way you expect. Foundries are now offering that precision." Touchstone is currently engaged with TSMC at the 0.18µm node, but it doesn't rule out using a smaller process. "If it becomes more effective for us to scale down, then we will make that move," Dr Fonderie said. "It's not sensible at the moment, but when it is, it will be much easier for us to take advantage." He believes 0.18µm is the new analogue 'sweet spot'. "But anything from 0.13µm to 0.25µm is fine. There's a lot of activity focused on 0.18µm and the benefit of using this node is that you can include a good deal of digital support circuitry in the product." But he returned to process parameters. "It doesn't matter whether an amplifier, for example, is made on a 0.18µm or a 0.25µm process," he concluded. "What is necessary is good matching and it appears that these parameters will get better as the process geometry gets finer."