Electronic Design

Moving Programmable Analog To A Higher Design Platform

For years, analog and mixed-signal IC suppliers have frantically been trying to bring the benefits of programmability to the analog design world. Over time, sufficient progress has been made to narrow the gap between analog and digital designers, and the progress continues. Despite this, higher-level CAD tools aren't readily available. Plus, analog chips aren't crafted to fully exploit the software. In some cases, analog designers must learn a whole new language to program analog/mixed-signal parts. Basically, they have to either become software savvy, or else lag behind. If the application changes, reconfiguration is another battle.

Fortunately, key programmable-logic device (PLD) makers have stepped in to extend the advantages of field-programmable gate arrays (FPGAs) and PLDs to the analog world. This is better late than never. They're providing analog designers with a whole new suite of development tools to make their lives much easier. There are no more hassles of layout, parasitics, and interconnect delays. Also, the turnaround time is dramatically shorter.

Because this is only the beginning, the complexity is modest. The ac and dc performance is mediocre, and the choices are few. Functions are limited and bandwidth is only several hundred kilohertz. Initial releases are, therefore, being aimed at digital designers, as well as neophyte engineers with little or no analog design experience. This is a learning period in which these engineers can begin to explore these developments and familiarize themselves with the new hardware and accompanying software tools. They have set the stage for field-programmability and on-the-fly reconfigurable analog ICs.

Think back to the early days of FPGAs and PLDs. There wasn't a lot that any designer could do with mere hundreds of programmable gate arrays on-chip. Today, with millions of gates and easy availability of sophisticated development software tools, the situation is in favor of these technologies. Using such multimillion-gate PLDs and FPGAs, a designer can think of developing an ASIC or a complete system-on-a-chip (SoC) solution.

Likewise, as more players unveil their plans, the scenario for field- or in-system-programmable analog ICs begins to look bright too. Last year, there was only Lattice Semiconductor. This PLD maker pioneered the field with a simple slogan, "What you see is what you get." Extending its in-system-programmable PLD technology to the analog domain, the company unwrapped the first in-system-programmable analog chip, or ispPAC solution, backed by a user-friendly integrated design environment. Early this year, Lattice added a programmable filter chip to the roster. The company promises to keep pushing the technology to deliver more complex chips in the future.

On the heels of this announcement, Anadyne Microelectronics Ltd., based in Crewe, England, revealed its plans to enter this fray. After acquiring the field-programmable analog array (FPAA) technology from Motorola Inc., Anadyne's designers quickly launched their first derivative of FPAA, along with accompanying CAD support. According to Anadyne's president, Mike Kay, the FPAA represents a new direction for analog circuit designers. It brings to analog what FPGAs brought to digital.

Now, another startup is leveraging the PLD and FPGA technologies to deliver programmable analog solutions to SoC builders. Because of confidentiality restrictions by which we must abide, more cannot be divulged about this company. Certainly other PLD suppliers aren't far behind. In short, the field is rapidly evolving. Soon, there will be many more suppliers and more sophisticated offerings. But will such advances attract hard-core analog circuit designers? I hope so. Please send me your thoughts on this evolution.

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