SNVSAH5A September 2017 – May 2020 LM73605 , LM73606
PRODUCTION DATA.
The driver of the HS switch requires a bias voltage higher than the VIN voltage. The capacitor, CBOOT in the Simplified Schematic, connected between CBOOT and SW pins works as a charge pump to boost voltage on the CBOOT pin to (VSW + VCC). A boot diode is integrated on the die to minimize external component count. TI recommends a high-quality 0.47-µF, 6.3-V or higher voltage ceramic capacitor for CBOOT. The VBOOT_UVLO threshold is designed to maintain proper HS switch operation. If the CBOOT is not charged above this voltage with respect to SW, the device initiates a charging sequence using the LS switch before turning on the HS switch.