Definition

Quad Flat No-lead (QFN) is a leadless surface-mount package with contact pads on the bottom perimeter and typically an exposed thermal pad in the center. QFNs offer smaller size, better thermal performance, and lower inductance than leaded packages like QFP. The exposed pad requires via-in-pad or closely spaced thermal vias for heat transfer to inner layers. QFN assembly requires careful stencil design to avoid voids under the thermal pad that cause overheating. Standard pitches are 0.5mm and 0.65mm.