The LM74502-Q1 has an enable pin, EN/UVLO. The enable pin allows for the gate driver to be either enabled or disabled by an external signal. If the EN/UVLO pin voltage is greater than the rising threshold, the gate driver and charge pump operates as described in Gate Driver and Charge Pump sections. If the enable pin voltage is less than the input low threshold, the charge pump and gate driver are disabled placing the LM74502-Q1 in shutdown mode. The EN/UVLO pin can withstand a voltage as large as 65 V and as low as –65 V. This feature allows for the EN/UVLO pin to be connected directly to the VS pin if enable functionality is not needed. In conditions where EN/UVLO is left floating, the internal sink current of 3 uA pulls EN/UVLO pin low and disables the device.

An external resistor divider connected from input to EN/UVLO to ground can be used to implement the input Undervoltage Lockout (UVLO) functionality. When EN/UVLO pin voltage is lower than UVLO comparator falling threshold (V_EN/UVLOR) but higher than enable falling threshold (V_ENF), the device disables gate drive voltage, however, charge pump is kept on. This action ensures quick recovery of gate drive when UVLO condition is removed. If UVLO functionality is not required, connect EN/UVLO pin to VS.