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Where Art Thou Analog IP?

Most of my time is spent writing about digital design and verification and I am about to start running a series on intellectual property (IP). Sadly, I can’t say that I am terribly surprised that I have had no submission on the subject of analog IP.

Why is that? We know analog IP does exist and probably should be in wider use, but for some reason it is another area where analog design and integration has stuck around in the old world. It's time that changed.

Clearly, without abstractions in the analog world, the only IP that exists is hard IP. This is IP that has already been through the layout process, has been characterized and verified on a specific foundry process, and is ready to be used. This means that the business is unlikely to be as profitable as the digital IP business where soft IP can be shipped and the layout and routing left to the chip designer. But then again, hard IP, which clearly contains more of the back-end effort, is probably not as cheap as soft digital IP. Some of these analog IP blocks contain very deep technical knowledge about the interface or subject that is unlikely to be shared by too many people in the industry, meaning that it is possibly a better implementation than most companies would be able to create on their own.

These days, almost every complex chip targeting cellphones, tablets, set-top boxes, automotive, and many others will contain one or more IP blocks. There may be blocks such as SerDes, PLLs, PHYs, DACs, and ADCs. An increasing number of sensors are being included these days, and this phenomenon will likely increase as additional chips are made for the Internet of Things (IoT). These chips require very high levels of integration and ultra-low power consumption especially since many of them have to scavenge power. Assuming that design times do not increase, there will be a growing pressure to start using pre-existing analog blocks.

The first question to come up probably is can we leverage a previous design and thus do internal reuse. This is probably going on a lot already and resembles soft IP in the digital world. You may have the design, but you will have to redo the layout, and it is likely that several other things will change between applications as well. This could include:

  • different clock frequency
  • different voltage
  • new technology node that will affect the sizing of everything and thus all of the parasitics
  • changes in chip layout that may affect signal integrity.

But there could also be changes in the requirements for the device that may require small changes in the design. As soon as this happens, all of the verification that had been performed goes out the window and you really are back to square one.

Many foundries supply a library of analog blocks, and there is a clear reason why they would like you to use those — it makes it more difficult for you to go to a different fab. Using these could also complicate the ability to get a second source if that is important to you. But there are third-party analog IP suppliers. Some of these are small companies that may give pause for thought, but large established IP companies also offer analog blocks. There are also companies that will customize blocks for your specific needs.

Given the many sources, what are the biggest issues or obstacles that you see preventing more widespread adoption of analog IP?

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9 comments on “Where Art Thou Analog IP?

  1. SunitaT
    April 23, 2013

    new technology node that will affect the sizing of everything and
    thus all of the parasitics

    Analog IP reuse is not straight forward because technology node change/migration brings in new set of challenges. Analog IP which worked in one technology node may necessarily not work in other technology node. This may occur due to several reasons. Like voltage scaling have impact on signal to noise ratio and signal propagation time. Even in same technology node, change in some of the specification results issue in the reuse of the design.

  2. SunitaT
    April 23, 2013

    “Clearly, without abstractions in the analog world, the only IP that
    exists is hard IP. This is IP that has already been through the layout
    process, has been characterized and verified on a specific foundry
    process, and is ready to be used.”

    Analog IP processed by one foundry may behave differently when
    processed by another foundry. It is also not very uncommon to observe
    different analog behavior for the same analog IP at a common
    technology node due to difference in process technology of the
    foundries.

  3. SunitaT
    April 23, 2013

    Analog IP which has worked perfectly fine in one scenario may not
    behave same in other scenario. For example, PLL integrated in wireless
    application with some digital clock frequency of microcontroller may
    not behave the same when compared with wireline application at a
    different frequency due to different noise environment.

  4. Davidled
    April 24, 2013

    In the view point of chip designer, they use the previous block in the future project. For example, in the case of PLL design, it can be minor changed for different frequency with noise. Of course, there are required for some change depending on frequency band. But still designer got a lot of benefit from usage of previous IP, as long as fundamental circuit is not changed.

  5. TheMeasurementBlues
    May 6, 2013

    Brian wrote “I have had no submission on the subject of analog IP.”

    That's because analog is black magic.

  6. Brad Albing
    May 6, 2013

    Well, to you maybe. For some of us, we become one with our designs.

  7. TheMeasurementBlues
    May 6, 2013

    Like I said to Brian “analog is black magic.”

    Analog IP which has worked perfectly fine in one scenario may not
    behave same in other scenario.

  8. Brad Albing
    May 7, 2013

    I'm pretty sure that's one of the corollaries to Murphy's Laws: Identical systems in identical situations will behave differently.”

  9. Brad Albing
    May 14, 2013

    You pretty much must reuse existing IP. If everytime you had to start from scratch, it would take way to long to create new devices.

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