The nFAULT pin has an open-drain output and should be pulled up to a 5-V or 3.3-V supply. When a fault is detected, the nFAULT line is logic low. For a 5-V pullup the nFAULT pin can be tied to the DVDD pin with a resistor (see the Section 8 section). For a 3.3-V pullup, an external 3.3-V supply must be used.

Figure 7-10 nFAULT Pin

During the device power-up sequence, or when exiting sleep mode, the nFAULT pin is held low until the digital core is alive and functional. This low level signal on the nFAULT line does not represent a fault condition. The signal can be used by the external MCU to determine when the digital core of the device is ready; however, this does not mean that the device is ready to accept input commands via the INx pins.