SMF4L 400W Surface Mount Diodes Littelfuse SMF4L 400W Surface Mount Diodes consist of a SOD-123FL small and flat lead low-profile package designed to protect sensitive electronic equipment from voltage transients induced by lightning and other transient voltage events. The SMF4L features 400W peak pulse power capability at 10/1000µs waveform with a repetition rate (duty cycle) of 0.1%. The diodes are compatible with industrial standard package SOD-123FL and offer a low inductance with excellent clamping capability in a low profile package of 0.98 maximum height.