ISL6420B Datasheet, PDF (18/20 Pages) Intersil Corporation – Advanced Single Synchronous Buck Pulse-Width Modulation (PWM) Controller

ISL6420B
Schottky Selection
Rectifier D2 is a clamp that catches the negative inductor
swing during the dead time between turning off the lower
MOSFET and turning on the upper MOSFET. The diode must
be a Schottky type to prevent the parasitic MOSFET body
diode from conducting. It is acceptable to omit the diode and
let the body diode of the lower MOSFET clamp the negative
inductor swing, but efficiency will drop one or two percent as a
result. The diode's rated reverse breakdown voltage must be
greater than the maximum input voltage.
18
FN6901.0
April 27, 2009