Analog & Digital Chips On The Same Silicon

jukal writes "Forbes.com writes: "Intel Corp. Monday announced plans to put some functions of analog and digital chips onto the same piece of silicon, its latest push into the communications semiconductor industry.", "which will be available early in 2004, could lead to a single-chip hand-held device that offers cellular phone, wireless-data-network and other connection services.", so, I quess this will be a competitor to the Texas Instruments' OMAP chip?"

Comments

Phone size

[Winterblink]

As if we need even smaller cell phones. Oh I can't wait for the day when I lose my cell phone in my EAR.

Re:Phone size

[silverhalide]

Have no fear, you'll lose it in your mouth first!

Not new, it's called Mixed signal.

[msgmonkey]

A large section of embedded IC's have digital & analog on one chip. This has been done for years, just beacuse Intel are now doing it does n't make it news.

Re:Not new, it's called Mixed signal.

[jaoswald]

You are completely right about mixed signal chips being a reality for a long time: you don't need to look any further than a video card in your computer to see that. Intel mentions "silicon radio" as if it is a new idea, but a company already exists called Cambridge Silicon Radio, so you can see it isn't just Intel in this business.

I have a feeling that something important is being left out of this article. If you look at the original press release you see that it is a total mishmash of different Intel developments. The poor journalist was stuck trying to find a lead in this story (other than "Intel has bunches o' innovation") and zeroed in on the part that mentioned Moore's law, which he had heard before.

The most interesting part that I see is the tunable laser using silicon photonics. Si has an indirect band-gap, which makes it not very good for making lasers and optical devices. That could be big news.

Re:Oh goodie....

[GigsVT]

Single chip calculators have been around for several year. Single chip remote controls, single chip alarm clocks, single chip video transmitters... It's all there, you just don't see it, that's sort of the point.

Single Chiped Celluar!

[famazza]

This means that instead of two-chips cellular will have single-chip celluar!

That's a huge advance!

RIAA immedietly files to block the technology

[doublem]

RIAA Spokeswoman Hillary Rosen immedietly began a legal action to block this technology. "It would allow for the creation of Analog to digital and digital to Analog translation devices! It must be stopped. All industry must bow before RIAA profits! All technology that can be used to pirate music must be destroyed! Kill them! Hang them all!"

Re:This is new?

[jaoswald]

An A-D converter is not necessarily a truly hybrid device. The point is that there are transistors that are good for producing gain, possibly at high frequencies. Those make up what are generically called "linear" chips. Mostly op-amps and so on.
These tend to be bipolar junction transistors or related technologies. The key thing is that they tend to pass current all the time.

Then, there are transistors which are good for switching, for creating logic gates & CPU logic. These tend to be CMOS field-effect transistors which are designed to only pass current when they are switching, in order to reduce power consumption so that you can raise the clock rate to obscene levels. However, logic gates are ideally non-linear: either on or off, with nothing in between.

The problem is that these technologies are differently optimized, and aren't naturally compatible. Coming up with a process that can produce nice linear transistors along with high-performance logic gates is tough. You can also try to approach it from the other end: come up with some kind of circuit which can make nicer amplifiers out of lousy transistors.

That's what makes true mixed-signal chips difficult: you either give up linear behavior, or increase current draw, or you give up the gate density and clock performance.

Problem with Mixed Signal Chips Like This

[Anonymous Coward]

As ambitious as this effort is, there are significant barriers to getting it to work properly.

First off, analog and digital go hand in hand. All digital circuits are essentially analog circuits operating in a non-linear range. However, high-frequency analog circuitry is particularly problematic. Even basic structures such as phase locked loops and analog-to-digital converters can generate a lot of on-chip noise, both in the silicon substrate itself and through parasitic coupling above it. For basic PLLs, you need a good 50-100 microns of space between it and the nearest logic gate. Higher-speed cores will require structures like isolation tubs and additional spacing, and will significantly hamper placement and routing of the remaining circuitry. In other words, it is very easy to run out of die space and/or introduce signal integrity problems.

Speaking of signal integrity problems, the smaller geometry ICs (0.18um feature size and below) are having their signal integrity problems get worse and worse. Noise, delay, and wire melt are common problems that need repair in the digital circuitry, and noise margins are getting razor thin as it is. Power distribution is also going to be a nightmare, considering that every analog block will need its own power, probably multiple FC lands per block. The thing is, the CAD tools aren't there yet. Chips are still taped out with marginal signal integrity problems despite "simulating ok". Mind you, the analog portions are given a wide berth as I mentioned above, but who knows if they've fully covered this in the CAD tools or in the formulation of the design methodology. Lots of test vehicle chips will be needed.

Also, integrating passives can be precarious at best. Chips can have elements such as inductors and capacitors, but they're not area efficient at all, and you'll need external passive components anyway. And if you want power regulation for charging functions and battery regulation, fuggeddaboudit. These structures are particularly area inefficient. I don't think that this is what they're trying to do, but if you think we'll have literally everything integrated onto one chip, it won't happen.

I also have very little faith in the process technologies. If you look at some of the problems that 0.13um manufacturing has had with via voids and low-k dielectric brittleness that have been shown in the trade journals lately, I'd be very nervous with releasing something like this with just anyone's process. TI seems to be better for manufacturability, but TSMC or UMC? Don't count on it - yet. To accommodate the highly integrated nature of this device, they need a small process technology with very rigorous manufacturing capabilities to avoid some of these problems.

Finally, integrating analog RF and digital requires advanced packaging technologies. If I've got the output to an antenna block in my chip package, how do I get it out? Most likely, this would go into a flip-chip package to accommodate the high integrated nature of this. Well, the flip-chip redistribution layer, the package substrate, and the surrounding pins will all have to be very carefully designed so that the RF signal will be sufficiently isolated. On RF-only chips, this isn't a problem. Heck, they have fully-integrated Bluetooth chips. But Bluetooth only has enough power to reach 30 meters. We're talking a signal that has to reach several kilometers here. That's a difference. It's doable, but it is just another big constraint on the design.

Can they do it? I think they *might* be able to, but not without significant design effort. Personally, I think they're better off going with a multi-die package and leaving the RF block as a die right beside the other, and specially route through the substrate with its own power. Integrated doesn't always have to mean "everything on one chip". Just like gift wrapping multiple presents in the same wrapper, I think this would be a better way to go for this effort, and will deliver fruit MUCH faster than what I believe they're implying in the article.

Re:Pedantics...

[stevelinton]

Or, of course, silicone-geranium. Brightens up the garden without needing all that tedious watering.

NYT Article

[asv108]

There is also a NYT Article.