10-VSON (3x3) with exposed pad — the layout constraint
The TPS62044DRCR is a step-down buck regulator from Texas Instruments in a 10-VFDFN exposed pad package, also designated 10-VSON (3x3). The 0.50 mm pitch around the perimeter means two-layer boards can fan out the outer pins, but the centre pad requires at least a four-layer stack for effective thermal spreading in continuous 1.2A operation.
2.5V to 6V input, fixed 1.8V output at 1.2A
Input range is 2.5V minimum to 6V maximum, making it a fit for 3.3V or 5V rails. The output is fixed at 1.8V — no adjustable version in this order code, so the BOM must match that rail exactly. The 1.2A continuous output rating is the thermal design current; the part will deliver the rated current up to 85°C ambient with adequate PCB copper area under the exposed pad.
1.25 MHz switching with synchronous rectification
The fixed 1.25 MHz switching frequency keeps the inductor and output capacitor small — typical values are 2.2 µH to 4.7 µH and 10 µF ceramic. The 1.25 MHz fundamental is above the AM radio band, which simplifies EMI filtering in noise-sensitive designs.