4A buck in a 2x3 mm QFN — load budget and board fit
The TPS621361RGXT delivers 4A continuous output from a 3V to 17V input rail, switching at 1 MHz to keep the inductor and output capacitor physically small. The 11-VQFN-HR (2x3 mm) package is one of the smallest footprints for a 4A monolithic buck, but the 0.50 mm pitch exposed-pad land pattern demands a thermal via array and a controlled stencil — a 2-layer board with a solid ground plane under the pad is the minimum for full current capability. Synchronous rectification eliminates the external catch diode; the internal low-side FET handles the freewheeling path, which keeps the BOM to one inductor, two ceramic caps, and the feedback divider.
Output voltage range and adjustment
The adjustable output spans 0.8V to 12V, set by a resistor divider from the FB pin. The 0.8V minimum floor suits low-voltage core rails; the 12V ceiling covers most 12V intermediate-bus applications. The 1 MHz fixed switching frequency keeps the ripple amplitude predictable across the full output range.