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Design a Production-Ready Custom Mixed-Signal IC on Your Couch

We like to publish a variety of blogs on Planet Analog. Some provide purely technical information. Some have content that tends to promote a product line from the blogger's company. We are always happy to publish the former and shy away from the latter. Still, we sometimes receive submissions containing solid technical information along with material bordering on advertising. What to do? Let the reader know up front. The following is worth sharing, especially considering its timeliness after Scott Elder's recent blog.

Following up on Scott Elder's post about designing a custom IC, let's look at some of the ways to fabricate your own custom IC. Elder outlined a way to prototype fully custom mixed-signal chips for about $3,000. He proposed using inexpensive design tools and a way to reduce prototyping fabrication costs by utilizing the multi-project wafer (MPW) capabilities offered by a number of foundries.

I have a few thoughts on that proposed approach. First of all, it is a prototype-only solution. Since an MPW run is a shared wafer, you will still need to spend $60,000-$250,000 or more to buy a complete mask set to support production. Also, since there are many users sharing the MPW (including the fab itself), these runs often get delayed to give everybody a chance to get on board. Not always, but often, MPW runs can take six months.

Fully custom analog IC design is an art. It is hard to get good custom analog IC design experience. Many companies say you need 10 years of experience on the expensive EDA tools working at a variety of foundries before they will hire you. (That's a Catch-22, isn't it?)

Your first prototypes will likely have problems. OK, if you've been doing custom analog IC layout at a bunch of different foundries for decades, then maybe you can get your analog IC right the first time. For everybody else, a second or third spin will probably be required to meet your performance specs. A fully custom MPW approach to respins means that you will have to wait another 4-6 months to get revised silicon.

Analog is fun, but we cannot ignore digital. Combining analog and digital on the same IC is a great way to make some really cool stuff. We should have a low-cost, truly mixed-signal chip development flow. I'd like to describe a different approach to semi-custom mixed-signal IC development that is inexpensive, requires less expertise, reduces prototyping time, and eliminates the additional production mask charges.

What if you could create production-ready custom analog ICs like this?

  • Your prototypes are production-ready devices, so there's no need to pay extra tooling costs to go from prototypes to production.
  • Prototype runs take four weeks, instead of four months.
  • Respins also take four weeks.
  • You don't have to learn fully custom analog layout.
  • You also don't have to learn tons of details about a foundry's process design kit.
  • There's no need to write complicated design rule check (DRC) decks for the foundry.
  • You can combine analog, digital, processor, memory, and high-voltage electronics in the same design flow.

The approach we use at Triad Semiconductor is to provide a collection of analog and digital IP arranged in die on a semiconductor wafer and overlaid with a global routing fabric. These wafers are kept at the foundry in a partially processed state awaiting final configuration through the creation of vias to make the needed connections. A custom design can be mapped on to such a die using mixed-signal-aware place-and-route software and then sent to the foundry to be processed against staged wafers in a single via mask layer. This layer configures and interconnects the pre-fabricated resources into a custom mixed-signal device.

How do you do this? First, you need to acquire some design tools. We have one that provides a complete mixed-signal design and simulation environment. This tool, which is available for download, combines:

  • Hierarchical schematic capture
  • SPICE modeling
  • Digital HDL entry (VHDL and Verilog syntax-aware editor)
  • VHDL-AMS modeling (which speeds up high-level system simulations)
  • The ability to combine schematic netlists, SPICE, VHDL, Verilog, and VHDL-AMS in a unified simulation environment.

You design and simulate your entire circuit using this tool. Then you target your design at one of Triad's VCAs. The VCA family includes small devices with dozens of op-amps and 5,000 ASIC gates up to arrays with a million logic gates and 70+ op-amps. Next, instead of moving to a fully custom manual layout, you submit your mixed-signal netlist to Triad's ViaPath software for placing and routing on to a VCA.

But wait — I hear someone saying, “Analog layouts must be lovingly hand crafted from scratch for each and every design.” Can a place-and-route tool adequately connect analog circuits?

We've been working on VCAs and mixed-signal placing and routing since 2002. Our customers include defense, medical, industrial, automotive, and consumer customers with production volumes from hundreds to more than 10 million chips per year. ViaASIC applications combine high-precision, low-offset analog circuits, precision ADCs, high-voltage circuits, and wideband analog. These analog circuits are on the same VCA die with digital items, ARM Cortex-M0 processors, and nonvolatile memory.

Are these designs perfect? Of course not, but they are good enough for lots and lots of mixed-signal circuits, from strategic radiation-hardened applications to FDA Class II medical devices, hazardous gas sensors for first responders, and high-volume mobile computing devices. Basically, we have a team of designers constantly creating new mixed-signal IP, which is made available in the via-configurable fabric of a VCA.

After placing and routing, ViaPath outputs a set of configuration vias. This single via-only mask layer is sent to the foundry and processed against staged wafers. This approach reduces mask charges and fabrication time, and the process is inherently DRC-correct.

Using our software, you can develop your own mixed-signal production-ready ViaASICs for less than $10,000. Our tool can be used to design analog or mixed-signal circuits. At present, access is invitation-only, but in the coming quarters, we will be expanding access. If you have an application that would benefit from ViaASIC integration right now, feel free to contact me and request access to the full flow.

Let us know below whether this information was useful.

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9 comments on “Design a Production-Ready Custom Mixed-Signal IC on Your Couch

  1. Bob @ JVD Inc.
    April 24, 2013

    Reid,

     

    Your comments are spot-on.

  2. eafpres
    April 25, 2013

    Hi Reid–very interesting approach.  Reading your blog, I'm guessing Triad has a few million $ invested in teeing this up (I'm not including any capital–just the engineering time, process debug, software development, and cost of inventory of partially processed wafers etc.)?  Perhaps some of that was orginally offset by NRE charges to earlier customers?

    Bottom line is you have taken on a lot of the up-front financial risk; the trade off is the users are pretty much married to Triad.  Are you able to say how many designs you have completed this way, and roughly how many a year can be handled?

  3. Via Monger
    April 25, 2013

    Yes, we've made signficant investments in our technology, methodology and EDA tools going back to 2002. Most all of our VCAs have been designed with lead customers and they have all paid some NRE. Since we will later utilize the base via configurable array (VCA) for other customers, we never charge the first customer the full NRE needed to develop the array. Instead, we amortize the cost to develop the arrays, flow and EDA software across the marketplace. What keeps us pretty excited is that unlike a digital structured array or FPGA, our analog-ish arrays done need to constantly scale to a new process node to be viable in the marketplace. 

    So, to your question about our capacity and customer volumes. We can handle dozens of customers per year in what we call a turnkey engagement. In a turnkey engagement, Triad's engineers provide the mixed-signal design engineering from start to finish.

    We are proudly a private company so I won't give out numbers of customer etc but our financials can be publicly found since we are on the Inc 500 list of fastest growing private companies.

    Our ViaDesigner EDA software is what will enable true scaling of this technology. With the engineer doing his mixed-signal ViaASIC design in ViaDesigner, we can easily support “FPGA-industry” number of designs a year from a prototype fabrication perspect. The FPGA industry has 100,000 design starts per year — we are shooting for 1,000 to 10,000 when this approach is fully baked and adopted (that's our hopes anyway – execution required).

  4. mtripoli
    May 1, 2013

    Hi Reid. Just as I was thrilled to see Scott Elders post, I am as equally excited (more perhaps) to read this one. As I had mentioned, I have in mind a few devices that, though relatively simple, would make producing product much more efficient than the discrete approach we now take. I have looked at commercial products such as programmable analog (Anadigm) and such but these still have short comings. The idea that one can have both analog and digital frankly makes my head swim with possibilities.

    A couple of questions come to mind; from the initial (for discussion sake) $10,000 how many devices would come from this run? Secondly, given that you know the die size and structure ahead of time, can you ball park the device cost in small production runs, say 50,000 and 100,000 units? Having done semi-custom devices in the past (microcontroller based ROM masked “sound chips” from Sunplus, Alpha Semi, etc.) I'm aware that it is a volume based business, however if you can give some idea it would be very helpful. I'd be very interested in seeing the specifications for the devices available (op amps, etc.). How does one get an “invite”? Thanks for the post! 

  5. Via Monger
    May 1, 2013

    A prototyping run provides 50 parts or $200/part.

    Production pricing is a function of:

    1) Die size – which particular VCA from Triad you select

    2) Package (pin count & package type)

    3) Production test requirements

    4) Production volume

    We have a range of VCA die that go from 4mm2 up to 100mm2 so prices vary a bunch but for volumes in the 50K to 100K range you can think of prices from $3 to $8 depending on the variables above.

    Right now, to get early access to the flow we simply need to take a look at your design under NDA and make sure it is a good fit.

  6. mtripoli
    May 1, 2013

    Thanks for the info. I just watched the “ViaDesigner Intro” on Youtube. Very exciting technology. Interestingly enough, this video describes one of the “devices” I have in mind. I also filled out the form for the trial at the Triad website.

    http://www.youtube.com/watch?v=V2Eb9g3QpK8

  7. EMCgenius
    May 1, 2013

    The editor would have choked less if you had mentioned your two or three closest competitors.  A great article talks about technology as such, and it is fair if it just so happens to use your product offering as an example.  If you're as good as you say you are, checking your competitors will help convince us of that.  If my project is a slant fit at best to what you offer, and brand x fits better, then you have done us both a favor.  If the competitor is better at exactly what you do, hiding it from us won't help.  You are part of a community here, and should approach writing for this forum from that perspective.

     

  8. Via Monger
    May 1, 2013

    I agree with your comments for balance. I do tends towards preachy when I talk about our stuff…

    On the competitive landscape I would list at least the following:

    • “Inertia Corp” – bit of a joke but I'll explain
    • Cypress PSOC
    • Anadigm FPAA
    • Microsemi SmartFusion Mixed-Signal FPGA
    • Xilinx newest FPGA with some 3D-stacked analog
    • Full-Custom Mixed-Signal ASIC

    I'm not trying to be too cute with the “Inertia Corp” reference but for most modest volume customers the choice tends to be do nothing (Inertia Corp) and stick with a discrete PCB design or go to a full-custom mixed-signal ASIC.

    I always tell folks that if your designs fits on a PSOC, FPAA or other field-programmable device and it meets your performance, power, footprint and price targets you should use those solutions because they have zero development NRE.

    In other posts on this site, I try to make the case for a single-mask, via-configurable approach to analog compared the field-programmable (active transistor) approach. But, since I'm the one spouting out “use it if it is good enough” I should eat my own medicine. If a field-programmable analog device satisfies your project goals then that's the way to go. If not, we seek to offer a low cost way to allow you to design your own integrated analog & digital solution. 

  9. EMCgenius
    May 1, 2013

    Thanks for the information.  I really did like the article, and your competition owes you the same courtesy when they get to brag.

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