ZHCSNW4 October 2022 LM5012-Q1
PRODUCTION DATA
The LM5012-Q1 integrates an N-channel buck switch and an associated floating high-side gate driver. The gate-driver circuit works in conjunction with an external bootstrap capacitor and an internal high-voltage bootstrap diode. A high-quality 2.2-nF, 50-V X7R ceramic capacitor connected between the BST and SW pins provides the voltage to the high-side driver during the buck switch on time. During the off time, the SW pin is pulled down to approximately 0 V, and the bootstrap capacitor charges from the internal VCC through the internal bootstrap diode. The minimum off timer, set to 50 ns (typical), ensures a minimum time each cycle to recharge the bootstrap capacitor. When the on time is less than 300 ns, the minimum off timer is forced to 250 ns to ensure that the BST capacitor is charged in a single cycle. This is vital during wake-up from sleep mode when the BST capacitor is most likely discharged.