SNVSBA0D February 2020 – August 2021 LM61480-Q1 , LM61495-Q1 , LM62460-Q1
A BOOT resistor can be connected between the CBOOT and RBOOT pins to slow the rise-time of the SW node. If EMI performance is not critical, these two pins can be shorted. If EMI is critical, use a 0-Ω placeholder. The value can be increased if additional EMI margin is required. Increase to 200 Ω as a first step. This slows the rise-time of the SW node, reducing EMI at hundreds of MHz by a few dBµV. This is at the expense of about 0.3% efficiency at 400 kHz at 10 A. Use 50 Ω for a similar efficiency drop at 2.2 MHz at 6 A. In this example, 0 Ω is chosen to maximize efficiency. Continue to increase the value of RBOOT to further improve high-frequency EMI emissions at the expense of more efficiency. RBOOT connected to pins RBOOT and CBOOT can be any value between a short and an open without triggering BOOT UVLO.