Place the VDD capacitor as close
as possible between the VDD terminal and GND of the UCCx808-x, tracked directly
to both terminals.
A small, external filter
capacitor is recommended on the CS terminal. Track the filter capacitor as
directly as possible from the CS to GND terminal.
The tracking and layout of the FB
terminal and connecting components is critical to minimize noise pick-up and
interference in the magnetic sensing block. Minimize the total surface area of
trances on the FB net.
The OUTA/OUTB terminal has high
internal sink or source current capability. An external gate resistor is
recommended. The value depends on the choice of power MOSFET, efficiency and EMI
considerations. A pulldown resistor on the gate of the external MOSFET is
recommended to prevent the MOSFET gate from floating on if there is an
open-circuit error in the gate drive path.