Out in Front: May 9, 1996
Probing minuscule leads on QFPs and TSOPs that have leads spaced on centers as close as 0.3 mm is not a job for the faint of heart or for anyone who lacks patience, a steady hand, excellent vision, a brightly lit workspace, and a good optical magnifier. Even if you possess all of these prerequisites, one more is virtually essential—a set of thoughtfully designed, miniature clip-on probes. If the probes aren't right, you probably should look for some other way of making the connection.
Emulation Technology has spent a lot of time looking for ways to construct tiny test clips whose characteristics can be controlled to more than 300 MHz, that do not distort 100-MHz waveforms, and that are rugged and usable enough to meet users' needs. The company believes that its MicroGrabbers, which cost $32.50 each (10), are the best solution.
Among the MicroGrabbers' features are an insulated metal barrel to keep adjacent clips from shorting to each other, a stackable tongue-in-groove design that makes groups of clips more stable on device leads than individual clips, and an actuator that lets you easily open a clip's jaws using just your thumb and forefinger. Some other clip designs force you to use both hands to attach a clip. Emulation Technology points out that, despite the existence of several alternative probing technologies (IEEE-1149.1 boundary-scan, for example) and the skill needed to use ultraminiature clips, the tiny clips are still a popular item with project managers. First, the clips are dramatically less costly than competing probing devices. Second, clips are reusable on a variety of package styles, whereas nearly all specialized probing adapters work with packages of only one type and size. Third, clips are available even before new packages become available. Specialized adapters can take months to reach the market; some never do if the package for which they were designed proves unpopular.
—by Dan Strassberg
Emulation Technology, Santa Clara, CA, (408) 982-0660, fax (408) 982-0664.