The TPS2585x-Q1 provides an integrated bootstrap voltage regulator. A small capacitor between the BOOT and SW pins provides the gate drive voltage for the high-side MOSFET. The BOOT capacitor is refreshed when the high-side MOSFET is off and the low-side switch conducts. The recommended value of the BOOT capacitor is 100 nF. A ceramic capacitor with an X7R or X5R grade dielectric with a voltage rating of 10 V or higher is recommended for stable performance over temperature and voltage. The BOOT rail has a UVLO to protect the chip from operation with too little bias, and is typically 2.2 V. If the BOOT capacitor voltage drops below the UVLO threshold, the device initiates a charging sequence using the low-side FET before attempting to turn on the high-side device.