The latest post from CUI's Power Forward blog discusses an "under the radar” movement in the semiconductor industry that is shifting digital power from recommended to required.
The article begins, ”Recommended, highly recommended, and required are terms that are consistently thrown about in datasheets and marketing materials at all levels. Unfortunately there isn’t any IEEE definition for each of those terms and it is up to the user to interpret the vendor’s meaning. For the most part, no one likes to use the word required in their technical documentation because that locks it in as part of the solution and could potentially be used against them by their competitors.
Required is not a term that has been synonymous with digital power up to this point. However, there has been an “under the radar” movement in the semiconductor industry to begin requiring a “dynamically adjustable” output voltage. This movement began in ASICs and is now migrating to general release ICs. And it has come as a surprise to most engineers, leaving them scrambling to find a solution for this new requirement.
As further evidence of this, the PMBus working group recently announced and presented a proposed transition to a v1.3 of the PMBus specification as well as a new PMBus+ that would add an adaptive voltage scaling bus (AVSBus) to the new revision. The AVSBus is an additional 3-wire serial bus, which is used specifically for voltage scaling and is considerably faster than the existing SMBus. These updates to the PMBus specification would allow the industry to standardize to the new requirement rather than trying to implement a series of proprietary solutions now required by some of these chip vendors.
Some good information on PMBus and the proposed changes, including the addition of AVSBus, can be found at the PMBus website."