The VR_FAULT# pin is an open drain output, which alerts the system to potentially catastrophic power supply faults. The VR_FAULT# pin is an open drain structure. Connect an external pull-up resistor to this pin.

Only the most critical fault conditions assert the VR_FAULT# pin. Fault responses configured to be ignored, do not assert the VR_FAULT# pin. The VR_FAULT_CONFIG PMBus command provides some options to control which fault conditions cause this pin to assert.

Fault conditions which assert the VR_FAULT# pin include:

• Over-voltage fault (including pre-bias OVP, fixed OVP, and tracking OVP)
• Powerstage fault (TAO_HIGH)
• Input overcurrent fault
• Output overcurrent fault (configurable)
• Over-temperature fault (configurable)
• Faults from channel A only, or channel A+B (configurable)