SLVSDA7E February 2017 – August 2019 TPS61178
The bootstrap capacitor between the BST and SW pin supplies the gate current to charge the high-side FET device gate during each cycle’s turn-on and also supplies charge for the bootstrap capacitor. The recommended value of the bootstrap capacitor is 0.1 µF to 1 µF. CBST should be a good quality, low ESR, ceramic capacitor located at the pins of the device to minimize potentially damaging voltage transients caused by trace inductance. A value of 0.1 µF was selected for this design example.