ZHCSCO8E June 2014 – May 2019 TPS65283 , TPS65283-1
PRODUCTION DATA.
The device has an integrated boot regulator and requires a small ceramic capacitor between the BST and LX pins to provide the gate drive voltage for the high-side MOSFET. The boot capacitor is charged when the BST pin voltage is less than VIN and BST-LX voltage is below regulation. The value of this ceramic capacitor should be 47 nF. TI recommends a ceramic capacitor with an X7R or X5R grade dielectric with a voltage rating of 10 V or higher because of the stable characteristics over temperature and voltage. To improve dropout, the device is designed to operate at 100% duty cycle as long as the BST to LX pin voltage is greater than the BST-LX UVLO threshold, which is typically 2.1 V. When the voltage between BST and LX drops below the BST-LX UVLO threshold, the high-side MOSFET is turned off and the low-side MOSFET is turned on allowing the boot capacitor to be recharged.