by James Montgomery, News Editor, Solid State Technology
July 16, 2007 – High-speed interfaces (e.g., PCI Express I and II, HyperTransport 2.0 and 3.0, XAUI, XDR, RapidIO, and InfiniBand) are increasingly being used to deliver faster data rates, but traditional “functional” testing becomes ineffective at ever-faster speeds (~>6Gbps). [See images above and below.] Sourcing test data from and receiving back to the device for recognition is simple and cheaper, but this “near-end” loopback method tends to result in incomplete testing and test escapes. Credence Systems Corp. says its new integrated test system, the Sapphire D-6432DFT, can help IC manufacturers flexibly and comprehensively test key variables impacting device and system performance.
Developed in partnership with AMD, the new tool combines at-speed loopback testing with jitter measurement and injection (as well as scan/functional tests and DC parametrics), offering 4x greater density than comparative offerings, the company claims. “Far-end loopback” techniques combine DFT with in-depth diagnostics of functional testing to lengthen the feedback path by placing the DUT in communication with an intelligent tester channel to enable production-level testing of high-speed buses (up to 16 lanes on a single instrument). Capabilities include simultaneous and parallel jitter injection and jitter measurement per lane (i.e., no need for additional instruments); full eye closure testing in voltage and time; integrated 400/800 Mbps data subsystem for scan/functional test; and increased detecting sensitivity to signal integrity issues. Receiver and transmitter channels can be used to deliver test vectors to the core logic and protocol stack, Credence says, and the tool offers access to device pins for full DC parametric testing.
Credence says it has more than 200 Sapphire D-6432DFT systems being used in production, including at AMD, where it is accelerating time-to-test and time-to-market of advanced products, achieving better coverage than a full functional test as well as offering “a very attractive cost-of-test proposition,” according to Pete Hodakievic, senior member of technical staff and manager of ATE technology at AMD, in a statement. “The increasing design challenges of high-speed bus interfaces together with even faster data rates necessitates more robust testing than what is possible with simple loadboard loopback techniques,” he said. “The Sapphire D-6432DFT enables us to perform high-speed loopback tests, DC parametric tests, and scan and functional tests — all in the same socketing.” — J.M.