It's About Time

Two thousand and nine was the year MEMS-based semiconductor oscillators became ubiquitous.  SiTime has shipped oscillators since 2007, but in 2009 we saw significantly larger volumes and wider applications.  Our sales increased quarter over quarter and our customer base steadily expanded.  But something else, something unexpected for me, happened last year.  We developed a large enough application range that I could no longer say where our oscillators were going.  While I’m sure our company databases have the information, it is more than a single person can follow.

I know we have millions of parts in flat panel televisions, I know we have parts in laptop PCs, and in networking equipment, cameras, phones, printers, set top boxes, disk drives, and many other applications.  But some of our customers are expanding their usage without cross-checking with us.  Our parts are simply working for them and they are building them into additional products.  One of our customers is ordering millions of parts for consumer applications.  I don’t know exactly for what, but they are happy with our parts, our delivery, and our quality.  I know this because they told us so, and they are steadily increasing their order rates.

That is what happened in 2009 – SiTime’s MEMS-based semiconductor oscillators began to significantly replace the legacy technology across a wide range of products.  It is likely as you read this post that you have used our oscillators.  Perhaps in your computer showing this text, the servers that sent the data, the network equipment that carried the data, the destination monitors in the airport through which you last flew, the phone on your desk.  Who knows, but millions of our parts are running in products around the world, and you may already be using them.

The quartz industry has a reputation for poor quality.  Some of it is because it is difficult to maintain consistency in quartz production.  However, part of it is self inflicted by the way quartz companies resell and relabel their product.

Because there are so many combinations of frequency, package, supply voltage, and various other specifications, there are thousands of “standard” quartz resonators.  Far too many to keep in stock or tool-up to build.  So the quartz industry has developed a resale-and-swap model where many, and in some cases most of the product a supplier may “manufacture” is actually bought from partners or even competitors.  This is how many quartz suppliers offer a wide range of product – they re-label parts from manufacturers.

In general re-labeling is fine and does not cause problems as long as the manufacturers are high quality and the relationships are durable and consistent.  But in this case the agreements are often ad-hoc and temporary.  They are often short term buy-sell deals rather than corporate relationships and there is often a lack of quality control.  Problem is that the customers think they are buying well qualified and stable product.  But really the parts are coming from wide ranges of unqualified manufacturers.  And because the ceramic quartz packages tend to look the same (there are only a few package manufacturers) the suppliers can change manufacturers.  They can and do even change manufacturers in the middle of their customer’s production runs.

Granted the high quality suppliers don’t do this, but many others do.  And chances are you may be buying untraceable product.  If your supplier changes manufacturers or the manufacturers change their process then the parts you buy might not work as you expect.  Specifically, they may not work like the ones you qualified.  They may shift in production; they may fail in your application circuit.  How does quartz fail?  Main problem is latent startup issues.  They may work well enough in your factory, but when they are cold or hot they may not start.  Scary?  You bet!

A few years ago my brother gave me a fine pair of audio speakers and I have recently been looking for a decent amp to drive them.  I want something well built, but not too expensive.  I am not a big electronics consumer and do not even have a TV, but since I am an analog engineer I am particular about amp quality.  That has sent me looking at and listening to amps in audiophile shops.  Most of the amps at these stores are solid state systems, but a few are vacuum tube designs.  The tube amps don’t perform very well, they distort the signals, but some people like “the tube sound”.  I don’t.

That got me thinking about tubes.  When I was a kid there were tubes everywhere.  They didn’t actually work very well, they burned out all the time, they had low gain, they came in only one polarity, they were hot enough to singe my fingers, and the voltages on them could shock me!  I didn’t like tubes, transistors were much better.

Nowadays tubes are used in just a few narrow applications.  High power microwave sources and RF amps still use tubes, and some audiophiles like they way their distortion sounds.  That is about it.  Application by application tubes have given way to smaller, higher performance, more efficient, and more reliable silicon transistors.  That is what is happening to quartz crystals.  Silicon is replacing them – application by application crystal oscillators are giving way to silicon oscillators.

Two years ago SiTime introduced the first commercial MEMS-based silicon timing solutions.  These support processor and general clocking applications and offer programmability, short lead times, and fantastic reliability.  Eighteen months ago we introduced low jitter oscillators for serial datacom applications.  Ten months ago we introduced high frequency oscillators (up to 800 MHz!) for very low jitter differential applications.  We also have spread spectrum and voltage controlled oscillators, and we are now releasing multi-frequency clock generators and low power oscillators to full production.  Our new SiT8003 takes less power than the vast majority of crystal oscillators, and supports battery operated and hand held applications.

So we have general purpose, low jitter, high frequency, spread spectrum, voltage controlled, multi-output, and low power oscillators.  And one by one quartz applications are moving to silicon.  Eventually quartz oscillators will be relegated to a few narrow applications.  Perhaps some audiophiles will like how they sound.

We are in the early stages of a historic change in the timing industry. This change is important and will impact the majority of electronic products. It is worth writing about and worth reading about.

I will discuss this change and the new timing industry it is creating. I will describe how Silicon Timing, with MEMS at its core, is replacing Quartz Timing.  I will describe how it will grow to impact crystals, oscillators, clock generators, clock distribution, and nearly all facets of electronic timing.

Here is the back story: Quartz crystals are used to build precise clock oscillators for electronic systems. They sequence computation and communications in the vast majority of electronic products, with about fourteen billion units sold this year. Quartz is available as resonators and oscillators. When people say “crystals” they are referring to passive resonators that must be electronically driven with external circuitry. When people say “oscillators” they mean active components that include resonators with drive circuitry in one or two packages. Quartz crystals and oscillators were first developed in 1920 and have been slowly and steady improved.

Silicon Timing is now replacing Quartz Timing. In Silicon Timing the precision timing signals are made by silicon resonators and silicon circuits. At the core of Silicon Timing is a technology called MEMS, which is an acronym for Microelectromechanical Systems. With MEMS technology we can build tiny mechanical components that sense motion, pressure, chemicals, or in this case vibrate at precise frequencies. The first MEMS oscillators were described in 1966; it has taken the intervening forty years to develop the technology and bring commercial products to market, but now Silicon Timing is commercially available and servicing a wide range of applications.

SiTime is the first company to produce commercial silicon oscillators and we lead the field. We are a spin-out of Bosch, the highly respected German automotive supplier and one of the world’s largest MEMS companies. Working at Bosch and Stanford University we developed the technology that would become SiTime. We realized that we had the final pieces of the technology necessary to make commercial Silicon Timing possible, and we set up SiTime to do that.

The figure below is an illustration of how new technologies displace old ones. It shows an incumbent with a dominant position and a new arrival growing and displacing the incumbent. The incumbent technology is not completely replaced, but usually survives in narrow applications, while the new technology grows to levels never achieved by the incumbent. We have seen this pattern repeated across every area of technology. This is how tractors replaced horses, airplanes replaced trains, transistors replaced tubes, and email replaced faxes.

This is how Silicon Timing is replacing Quartz Timing. How far along are we? Just starting.