The TPS6594-Q1 device can be configured to automatically start up from a first supply-detection (FSD) event detection. This feature is enabled by setting the FSD_MASK register bit to '0', and setting the NPWRON_SEL[1:0] registers bits to '10' or '11' to mask the functionality of the nPWRON/ENABLE pin. When the device is powered up from the NO SUPPLY state, the FSD detection is validated after the NVM default for this feature is loaded into the device memory.

When the FSD feature is enabled, the PMIC immediately powers up from the NO SUPPLY state to an operation state, configured by the STARTUP_DEST[1:0] bits when VCCA > VCCA_UV, while VCCA_UV gating is performed, and only when VCCA voltage monitoring is enabled (VCCA_VMON_EN = 1). After the device arrives the corresponding STARTUP_DEST[1:0] operation state, the MCU must setup the NSLEEP1 and NSLEEP2 signals accordingly before clearing the FSD_INT interrupt. Once the interrupt is cleared, the device either stays in the current state or moves to the destination state according to the state of the NSLEEP1/2 signals as specified in Table 8-20.