A Type-C USB Power Delivery Chip Faced Catastrophic Failure

A Type-C power delivery (PD) chip using a Type-C connector with Integrated V CONN power switch suffered catastrophic failure during application board power up and/or Type-C cable plug in. Failed devices showed signs of minor to severe damage on integrated V CONN power switch, ESD diodes, ESD rails of CC 1 and CC 2 and V CONN connector facing pins and bond wires of the V CONN pin.Accurate study, simulations and analysis of the V CONN switch, its layout, related parasitic BJT and potential SCR showed robustness of the design, layout and implementation. Also, different experiments with multiple failure analysis including emission and de-processing on multiple damaged parts provided a direction to understand the root cause. More investigation showed the off-chip boost converter on the application board was unstable and caused the problem. It over stressed the V CONN pin with a voltage much higher than its absolute maximum tolerance level which either killed the die immediately or wounded ESD structure and made it vulnerable against cable discharges.