Test System Adds Logic-Analyzer Capability At GHz Speeds

Design and test engineers pushing the IC limits of speed and density will want to check out IMS-Waves, a real-time, logic analyzer just added to the Vanguard tester from Integrated Measurement Systems Inc. (IMS). Vanguard, a high-speed IC validation system, targets the high-performance chip-design realm. This includes microprocessor design and high-density, custom logic, such as system-on-a-chip (SoC) devices, where critical timing problems often arise.

The instrument's new real-time software interfaces with the device-under-test (DUT) at up to 512 I/O test points. Each test point can handle gigahertz signals found in the latest high-speed designs. IMS utilizes a fly-by dual-coax cable system that's terminated at both ends to minimize round-trip delays and signal reflections (Fig. 1). Vanguard comes with a 1-Msample capture buffer.

IMS-Waves is a standard component of IMS-Tools that provides four major functions. The first is the ability to display simulated results based on the Digital Virtual Tester support. The next is showing timing signals sent from Vanguard to the DUT. The third function is a logic-analyzer display of signals from the DUT. The last is an analog display of the signals from the DUT. All results can be overlaid or displayed in synchronized windows.

Typically, test systems like Vanguard have remained in the realm of test engineers experienced in the intricacies of configuring the tester, running batch-oriented scripts, and interpreting results from the test system. IMS-WAVES provides a more interactive environment with a simpler interface to allow design engineers to exercise a chip, immediately see the results, and setup a new test.

Getting design engineers involved at this point of the development loop is critical for minimizing and correcting errors. It helps shorten the time-to-market window because problems discovered after this point are more difficult to isolate and correct.

The ability of IMS-Waves to overlay results from a test of a working chip makes it easier for design engineers to pinpoint the differences. Overlay information often results from a prior test of a working part.

Design and test engineers generate initial conditions and clock signals, as well as trace the results. Then, the results are compared against the simulated results and timing signals. Detecting problems would be tedious at best if IMS-Waves couldn't detect differences and marginal transitions. Color-coded waveforms highlight differences. IMS-Waves adds edge counting and searching that's handy when dealing with lots of information (Fig. 2). The ability to zoom in and out applies not only to logic signals but also to analog waveforms.

IMS Vanguard is a rather expensive piece of hardware and software. Although mobile, it isn't something you would want to move around regularly. Luckily, a network connection provides access to Vanguard and IMS-Waves, as well as to a collaborative debugging environment. Multiple workstations can run IMS-Waves, which allows designers and test engineers at remote locations to perform tests and compare results.

Remote collaboration supports synchronized windows plus independent views and overlays. Waveforms and data can be saved to analyze later or e-mail to a colleague. Multiple signal layouts provide different views of recorded information.

Integrated Measurement Systems Inc., 9525 S.W. Gemini Dr., Beaverton, OR 97008; (503) 626-7117; www.ims.com.