The digital interface, including the open-drain DIAG pin are functional as soon as VDD rises above the VDD_POR threshold. Analog functions, including the circuitry on the high-side, are enabled as soon as VDD rises above the analog under voltage lockout threshold VDD_UV .

At power-down, analog functions are disabled as VDD falls below the VDD_UV (falling) voltage level. The digital interface, including the open-drain DIAG pin remain functional until VDD drops below the VDD_POR (falling) voltage level. Figure 7-8 shows the different enable thresholds for the AMC3336-Q1.

Below the VDD_POR voltage level the digital output pins are not actively driven, that is they are in a high-impedance state but clamped to one diode-voltage above the VDD supply.