ZHCSO70A march 2023 – may 2023 LMR36501 , LMR36502
PRODUCTION DATA
The high-side switch driver circuit requires a bias voltage higher than VIN to ensure the HS switch is turned on. The capacitor connected between BOOT and SW works as a charge pump to boost voltage on the BOOT terminal to (SW + VCC). The boot diode is integrated on the LMR3650x die to minimize physical solution size. TI recommends a 100-nF capacitor rated for 10 V or higher for CBOOT. The BOOT rail has an UVLO setting. This UVLO has a threshold of VBOOT-UVLO and is typically set at 2.3 V. If the CBOOT capacitor is not charged above this voltage with respect to the SW pin, then the part initiates a charging sequence, turning on the low-side switch before attempting to turn on the high-side device.