Potential ESD hit? | Cypress Semiconductor
Potential ESD hit?
We use the CY7C68013A in the QFN56 package on our products. We have received a couple of boards back from the field that have worked and then aren't enumerated after being plugged into a computer. On closer inspection with a scope the I2C bus load executes as expected so the 8051 side seems to be functioning fine, however one board has a constant 1V on both D+/D-, and the other board has 500mV on D+/D-. There is no visible damage to the package, also after inspecting them under a microscope.
Does this sound like the USB port has taken a hit somehow, or could there be another explanation for this behaviour?