Robbie McAdam, group vice president, analogue products, Analog Devices

Digital technology continues to push process technology to its limits, with products now appearing on 45nm design rules. But it’s a different story for analogue electronics. There has always been a gap between the leading edge requirements of memory manufacturers and the ‘sweet spot’ for many analogue components. The gap appears to be getting wider. Is this a good or a bad thing? It depends on the particular analogue components. There is no doubt that analogue components follow a curve similar to that of Moore’s Law. The difference is the speed at which progress is made. McAdam said: “We’ve tracked data converter and linear products over a long time and you can see Moore’s Law being applied, but at different rates.” In McAdam’s opinion, data converters are, in general, shrinking to half their previous size over 24 months. “If you look at linear products – amps and so on – it’s more like 36 months because these devices are less dependent on lithography.” Like many others, McAdam believes the analogue ‘sweet spot’ remains at 0.25um, with power management devices suited to a 0.35um process. Nevertheless, there is work underway to support the manufacture of analogue parts on 90nm and 0.13µm processes. “But it’s more circuit innovation,” McAdam contended, “than pure lithography.” Having said that, McAdam noted advantages in pushing the envelope where data converters were concerned. “Our market share for data converters ranges from 37 to 50% and we increased that share last year. We take converters seriously because they represent 45% of the company’s business. In all converter technologies – particular continuous time sigma-delta and SAR – customers are pushing us to improve the power/speed product. Having said that, I believe it will be more likely that improvements in converter technology will come from circuit innovations, even though these products will be made on finer lithographies.” One of the areas on which Analog Devices is working is leakage. Already an important factor in the digital world, McAdam said solving the leakage problem at 65nm would bring better converter results. While noting there is industry interest in SoCs with analogue content, both McAdam believes smart partitioning will be the way to go. “Going to finer lithographies will bring disintegration,” McAdam contended. “Take tv chips, for example. Current devices are made on 65 or 90nm processes, but moving to 45nm. At 45nm, it’s increasingly hard to integrate precision analogue functions. So we’ll need smart partitioning, with the digital megachip on the finest lithography and the analogue components on the side.” Inevitably, there are exceptions. Where can finer lithographies make a difference? The consumer market, for one. “Digital is a big driver for analogue,” McAdam contended. “Digital tvs need sophisticated signal processing, cameras have moved to the digital world and xrays are going digital. All this means more analogue business.” With the design world moving towards a system base, Analog Devices is responding by establishing market focused groups. “We recently set up a medical group,” McAdam said, “because we need to understand the whole system.” One thing is for sure, however. Analogue design expertise is becoming scarcer. “Customers want us to do as much engineering work as possible,” McAdam concluded.