Logic Analyzers Never Die

But these traditional debugging instruments are taking on different forms now.


Logic analyzers, long a mainstay of chip design, are finding new demand for IoT devices—and frequently in different forms than in the past.

Once associated with big, bulky benchtop instruments, this technology has evolved significantly over the past 40 years. In some cases it has been moved into software, where the measurement results are more likely to be viewed upon a laptop screen or a big flat-screen display than in a tiny screen on the front of the logic analyzer. That is often paired with oscilloscopes as engineers test and debug circuit and system designs.

Debugging cellphones and PCs remain a key application for logic analyzers, but the number of applications is expanding.

The first instrument actually known by that name was the HP 5000A Logic Analyzer, introduced by Hewlett-Packard in 1973. Three months later, the HP 1601L debuted as a plug-in for the HP 180 oscilloscope mainframe line, providing a truly parallel instrument.

Fig. 1: The HP 1601L. Source: hpmemoryproject.org

The logic analyzer vendor base also transformed over the years. HP and Tektronix logic analyzers dominated the market for a long time. If you were a German engineer, you might have preferred logic analyzers from Kontron Electronics or Dolch Logic Instruments. Kontron has evolved into a supplier of embedded computer systems for a variety of industries. Volker Dolch, the founder and CEO of Dolch Logic Instruments, sold that company to BMW in 1987 and started Dolch Computer Systems, a supplier of portable instrumentation computers and rugged portable computers, which he sold in 1996. Kontron bought Dolch Computer Systems in 2005, after Volker Dolch’s death in 2003, and sold the rugged mobile platform to Azonix in 2007.

Fluke gave HP and Tek some competition in logic analyzers for a time in the 1980s. LeCroy was another rival.

Those four suppliers have gone through ownership changes in the past two decades. Danaher acquired Fluke in 1998 for $625 million, and it bought Tektronix in 2007 for $2.85 billion. Danaher split into two companies in 2015, with the Fortive spinoff taking along Fluke, Tek, and other acquisitions. Teledyne Technologies purchased LeCroy (now called Teledyne LeCroy) in 2012 for about $291 million.

HP’s original instrumentation business was spun off into Agilent Technologies in 1999 and spun off from Agilent as Keysight Technologies in 2014.

The logic analyzer market has another entrant, as well. National Instruments early on took “The software is the instrument” as a marketing catchphrase. The company took its software tools, combined them with field-programmable gate arrays, and eventually branched out into modular hardware platforms for instruments, too.

At last week’s DesignCon 2017 conference in Santa Clara, Calif., NI brought out the latest model in its VirtualBench All-In-One Instrument, the VB-8054, which pairs a four-channel, 500-megahertz mixed-signal oscilloscope with a new function generator, while also providing a digital multimeter; related instrument software; Ethernet, USB, and Wi-Fi connectivity to Windows, and Wi-Fi connectivity to the Apple iPad software application. It includes application programming interfaces to automate measurements in LabVIEW and C environments.

Screen Shot 2017-02-05 at 12.09.14 PM
Fig. 2: NI’s VirtualBench. Source: National Instruments

“Engineering workbenches and test systems are getting more and more crowded every day as technologies converge in the latest smart devices,” said Luke Schreier, director of automated test product marketing at NI. “VirtualBench provides the ideal combination of capability at performance levels that can legitimately replace five or more instruments needed to characterize new product designs or validate assembled units on a production floor. With 500 MHz of scope bandwidth and a faster generator in the latest model, VirtualBench meets the needs of even more engineers wrestling with how to lower their cost of capital equipment.”

Bill Driver, senior product marketing manager at NI, noted that mixed-signal oscilloscopes (MSOs) have been around for two decades, offering 100 or more channels, while some logic analyzers come equipped with scope cards.

“We don’t have a dedicated logic analyzer,” he said. “However, VirtualBench incorporates a logic analyzer and protocol decoding as part of its mixed signal oscilloscope. We saw the trend going toward multiple instruments in one,” Driver commented. “But it’s also many other instruments. So, we have a 34 channel digital logic analyzer, a function generator, a 5 ½ digit DMM, a programmable power supply, and DIO lines lumped in. That’s how we have addressed our first entry into the logic analyzer interactive use, is the VirtualBench. It’s probably more channels than most MSOs have. They are probably limited to eight, or 16 or 17.”

Dedicated logic analyzers are often being displaced by protocol analyzers, according to Driver.

VirtualBench can be used for test and measurement in the Internet of Things. “NI definitely sees this area and wants to continue providing products,” Driver said. “Although VirtualBench is our answer now, there are areas where we’re looking to expand, as well.” IoT devices typically don’t need 136 channels to debug, he added.

VirtualBench “is well-positioned because it has a true DMM,” Driver said. “The FGEN can also generate high quality waveforms. It’s better integrated than some of the MSOs that could be out there.”

NI isn’t alone in seeing this convergence, although companies tackle it differently. Jennie Grosslight, Keysight’s product manager for logic analyzer memory solutions, said logic analyzers can pull a trace from an oscilloscope into the logic analyzer waveform. A year ago, Keysight introduced the U4164A logic analyzer module and the related B4661A memory analysis software, for DDR4 and LPDDR4 memory chip design, debug, and validation.

Keysight U4614A logic analyzer
Fig. 3: Keysight U4614A logic analyzer. Source: Keysight

“The scope can work with the logic analyzer with signal integrity issues,” she said. “Let’s say you have an issue where you need the power of the logic analyzer triggering to trigger on exact data patterns on the bus and then you want to look at some specific channels of the bus to see what they’re doing from a scope standpoint where you have a far better signal integrity view and you’ve got much better resolution and response on the scope.”

Grosslight concluded, “The logic analyzer is an extraordinarily powerful general-purpose tool with specialty probing and software that provide unique insight, specifically in the use area of high-performance memory. HP, Hewlett-Packard, invented the logic analyzer. We go where no one else goes. As long as they can probe it, they can get insights.”

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