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My Favorite Entrepreneurs: #1: Robert Chao (ALD)


If you write about technology for a living, you talk to a lot of company founders.  Sometimes they hit home runs; sometimes they strike out. From time to time in these blogs, I’ll write about some.  Here’s one about a fellow many design engineers would like to emulate. He instantiated a basic technology and ever since, he’s been targeting products that embody it for unique applications.

Once or twice a year, I get a new product release from Advanced Linear Devices (ALD), his company.  I always know what the technology behind the new product is, because it's always the same -- Bob has a lock on a particular kind of floating-gate MOSFET that can be tuned for a threshold of zero volts.  What Bob has done over the years is study potential applications that can only be solved, or can far better be solved, by his technology.  Then he works with customers to tailor his process to the application.

The latest result of that approach is a small signal, low power, dual MOSFET with a dynamic current range that is more than eight orders of magnitude greater than anything that's been done, (or, Bob Says, is capable of being done with any other MOSFET technology. 

Explicitly, Bob's release says that the ALD212900A/ALD212900 family of dual high-precision monolithic N-Channel MOSFET arrays provides: operating ranges greater than 100,000,000:1. In other words, put in 30 pA; get 30 mA out. Zin is 2.5 x 1010Ω.  The devices can work with less than 5 nA of operating supply current while delivering typical output drive levels of more than 50 mA.)

In this implementation of the technology, Bob says that target applications include sensor arrays, energy harvesting systems, and low-power mobile devices.

A specific example, he says, would be, "a developer building high-end audio headset systems that need to closely match wide sensitivity of the human ear. If the desire is to accurately reproduce the wide range of sound levels between the faintest pin drop and the loudest boom, the dynamic range and high drive of these new devices is required.”

ALD's Floating Gate Technology

When the gate voltage on one of ALD's devices is set at 0.00 V (Trimming the threshold is the point of the floating gate.), the drain current is +20 µA at a VDS of 0.1 V. That allows circuit designs where the output voltage level is biased at or near the input voltage level.

Another neat benefit of the technology is that, since the quiescent gate charge is programmed at time of manufacture, there are no variations batch-to batch.

To get a notion of the range of applications Bob has dreamed up for his technology, take a look at the ALD Website.

TAGS: Analog
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