Electronic Design

Audio Interfaces Speak Volumnes In Analog

Overall, the industry is looking much more closely at making new products more power-aware. Even systems that are power-line operated are looking carefully at this. Obviously, the battery-operated systems have issues with power density in the battery and must contend with the mutually exclusive desires for longer battery life and smaller packaging.

Human interfaces are mostly analog, except keyboards. One growth area is occurring in audio interfaces, voice activation, and recognition for the systems. Audio inputs to equipment are enabled by smart microphones. To that end, an electret microphone with an embedded audio amplifier was recently released. In the future, expect to see codecs, filters, and amplifiers inside microphones. By adding some more mikes, an analog microphone array could perform acoustic and electronic beam forming. This would create very high-directionality microphones for applications like hands-free systems for vehicular cellular phones, a very noisy environment. The filters and other signal-processing electronics would help improve the noise rejection.

ELECTRONIC DESIGN (ED): Is the world moving more toward a single chip with everything integrated, or will the analog functions start coming out of the system-on-a-chip (SoC) and go into a separate analog subsystem?

Monticelli: The attempts to integrate decent analog functions will certainly continue, but the task will become harder. The fine-line digital processes need to have lower supply voltages, making the analog functions more difficult. In addition, the quality of the transistors is decreasing as they get smaller. That's probably okay for switching 1s and 0s, but inadequate for high-quality analog functions.

For high-performance systems, the analog functions will be separate from the digital. At the same time, the analog functions won't go toward more discrete components, but to a separate analog subsystem in a single package.

ED: Do you see the end-designers asking for more help in their designs?

Monticelli: The lower sophistication and experience of users requires that they must do a better job of design and support. They are finding that the customer is easily responsible for the system but can't be expert in enough facets of the design to be good in all areas of the design. A smarter customer will rely on their semiconductor vendor(s) to take responsibility for the analog and special-purpose mixed-signal portions of the design.

By adding value to the components with applications and even pc-board design support, National and its customers both benefit. The applications teams have been beefed up to supply this higher level of support to the users. This symbiotic relationship between the systems designers who are systems-aware and the semiconductor vendor who is application- and function-aware is only possible if both are willing to share expertise. The two parties need to interact at the engineering level. The arms-length transactions are an ar-chaic mode of behavior, and they hinder both groups.

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