The driver of the power switch (HS switch) requires bias higher than V_IN when the HS switch is ON. The capacitor connected between C_BOOT and SW works as a charge pump to boost voltage on the BOOT pin to (V_SW + V_CC). The boot diode is integrated on the LM76005-Q1 die to minimize physical size. TI recommends a 0.47-µF, 6.3-V or higher capacitor for C_BOOT. The V_{BOOT_UVLO} threshold is typically 2.2 V. If the C_BOOT capacitor is not charged above this voltage with respect to SW, the device initiates a charging sequence using the low-side FET.