The TPS25990 implements insertion delay at start-up to ensure the supply has stabilized before the device tries to turn on the power to the load. This is helpful in hotswap applications where a card is hot-plugged into a live backplane and can have some contact bounce before the card is firmly plugged into the connector. The device initially waits for the VDD supply to rise above the V_UVP threshold and all the internal bias voltages to settle. After that, the device remains off for an additional delay of t_INSDLY irrespective of the EN/UVLO pin condition. This action helps to prevent any unexpected behavior in the system if the device tries to turn on before the card has made firm contact with the backplane or if there is any supply ringing or noise during start-up.

The insertion delay can be changed by programming the INS_DLY register value in the Non-volatile memory/EEPROM using PMBus®.