Melexis CMOS Hall Sensors

Gideon Analytical Laboratories received five failed Melexis US2881 in a UA style package for failure analysis. The Melexis US881 is a bipolar Hall-effect switch designed in mixed signal CMOS technology. A Hall-effect sensor is a transducer that varies its output voltage in response to a magnetic field. When a current-carrying conductor is placed into a magnetic field, a voltage will be generated perpendicular to both the current and field. This is the Hall effect. Hall sensors can be used in switching, positioning, and detection applications.

All the devices had a resistive reading between the ground and output. In one failed device, massive destruction was encapsulating pins 2 and 3, as well as the circuitry. There was black residue found also, which was a result of carbon formed by burning epoxy in the absence of air. In another failed device, massive destruction and the black carbon residue was found around pins 2 and 3. Both damaged areas on the Melexis US2881s indicated very high heat because all the epoxy was carbonized. The ground wires were also pulled from the lead frames, causing an open. The damaged areas indicate that this was an Electrostatic discharge (ESD) event. ESD occurs when the sudden flow of electricity between two electrically charged objects caused by contact, an electrical short, or dielectric breakdown. ESD events are loaded with voltage.

Gideon Analytical Laboratories has been helping electronic companies by performing electronic failure analysis for over two decades. We have helped hundreds of companies save millions of dollars. With accurate and informative analysis that pinpoints the exact cause of failures, companies can adjust, improve, and correct their mistakes. If you need any kind of testing, call Gideon Analytical Laboratories. Whether it is ion chromatograph, moisture ingress, passivation, or anything else, we have the knowledge, the experience, and the equipment to get the job done.