JAJSKY7A February 2020 – November 2021 LM61480 , LM61495 , LM62460
PRODUCTION DATA
The driver of the power switch (HS switch) requires bias higher than VIN when the HS switch is ON. The capacitor connected between CBOOT and SW works as a charge pump to boost voltage on the CBOOT terminal to (SW + VCC). The boot diode is integrated on the LM6x4xx die to minimize the physical solution size. TI recommends a 100-nF capacitor rated for 10 V with X7R or better dielectric for the CBOOT capacitor. The boot (CBOOT) rail has a UVLO to protect the chip from operation with too little bias. This UVLO has a threshold of VBOOT_UVLO and is typically 2.1 V. If the CBOOT capacitor voltage drops below VBOOT_UVLO, then the device initiates a charging sequence using the low-side FET before attempting to turn on the high-side device.