Sep 27, 2013

Analog to Digital Convergence? Not So Fast!

In 1996, Dan Sheingold, the editor of Analog Devices’ magazine, Analog Dialogue, wrote an introduction in the “Editor's Notes” entitled: Analog Dialectic.
A little more than 30 years ago, the undersigned held a responsible technical marketing position with George A. Philbrick Researches, Inc., and was editor of a journal called "The Lightning Empiricist." For the edification of a sizeable portion of our readers who weren't around at the time, GAP/R, a company with annual sales of $6M, virtually owned the operational amplifier market-such as it was. The only significant competitors were then a lot smaller-Tom Brown's Burr-Brown Research Corporation, and Al Pearlman and the late Roger Noble's Nexus Research Laboratory, Inc.Aye, what's in a name? Do you find it interesting that "Research" was part of all three names? The founders of a new company, Ray Stata and Matt Lorber, did. They believed that the existing companies were getting prices* that would interest only researchers (who had much fatter budgets in those days), and that a significant industrial volume market for operational amplifier modules with a wide variety of performance was waiting to be tapped (ICs with decent performance were still pretty far over the horizon, so you didn't need venture capital to buy an expensive fab; you could still build modules in your own garage, or in this case, a loft-or was it a basement?-in Cambridge, MA).So they gave their company the highly descriptive and serviceable name, Analog Devices, Inc., and offered high-performance op amps at reasonable prices, along with strong application support. They were right, of course! The company's sales took off almost immediately. And ADI was aided by an incredible stroke of luck-both Philbrick and Nexus were acquired by the giant Teledyne, Inc., and merged. As often happens in such circumstances, the effect was like to putting two resistors in parallel; their joint effectiveness actually decreased. Not only that, but ADI was able to acquire the services of a number of talented, and perhaps disgruntled, former employees of Teledyne Philbrick Nexus, a move that proved synergistic. The rest is history! Should the next sentence read: "And with its primacy in analog devices, ADI lived happily ever after?"*For example, the P2 solid-state parametric electrometer was priced at $227 (in mid-1960s US dollars!)
Sheingold was a brilliant editor and I love the historical context.  But that wasn’t his point for this editorial.  Sheingold went on to discuss DSP as a complement to analog circuitry.  Dialectic is a form of argument (e.g., the Socratic method) and the argument started well before 1996 and continues on today.  Digital will make Analog obsolete, says one side.  Digital increases the demand for Analog, says the other side.  From my vantage point, the argument gets more and more irrelevant as time goes on.  The analog circuit design techniques involved in today’s “digital” chips is often the differentiating factor due to the incredibly fast switching speeds, ultra-low voltages and dynamic power management requirements.  The digital circuitry inside the most “analog” of analog chips is growing such that Verilog is no longer a foreign language.  No, from my vantage point the chasm between analog and digital peaked in 1978 with the AD574 12-bit monolithic Analog-to-Digital Converter (ADC) – thank you, Paul Brokaw.  The 10-bit predecessor, AD571 was introduced in the IEEE Journal of Solid-State Circuits, (Vol. SC-13, pp. 736-745, December 1978) as the first complete monolithic ADC.  The AD574 was much more popular and widely copied.  It had a co-bonded reference and required an external sample-and-hold amplifier (SHA) but it represents the turning point in my mind for analog and digital integration.  Prior to that, everything was separate.  Since then, the floodgates were open and the two continue to merge and blur the distinction.  It has been 35 years, so perhaps "floodgates" is not the right image.  This is analog, after all.

I welcome your opinion, so please add your comments below.  Also, as always, if you feel something is incorrect or incomplete, please let me know and I make the necessary corrections!

“Analog Dialectic” Analog Dialogue, Volume 30, Number 3, 1996 (editor Dan Sheingold)
“The Data Conversion Handbook”, Analog Devices, edited by Walt Kester

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