300 mA synchronous buck in a SOT-23-5
The TPS62240DDCR is a 300 mA synchronous step-down converter from Texas Instruments, switching at 2.25 MHz to keep external inductor and capacitor values small — a 2.2 µH inductor and 10 µF output cap are typical for a 1.8 V rail. Input range from 2 V to 6 V covers single-cell Li-Ion through 5 V regulated rails, and the adjustable output down to 0.6 V lets it feed low-voltage core rails for MCUs or FPGAs.
Sizing the output for a 1.8 V rail
With the adjustable output set by a resistor divider from the 0.6 V reference, generating 1.8 V is straightforward — the feedback pin voltage is regulated to 0.6 V, so the divider ratio is (1.8 / 0.6) - 1 = 2.0. The 300 mA continuous output current is adequate for powering a small MCU, a sensor module, or a wireless transceiver; derate above 85°C ambient per the datasheet thermal curve.
Housed in a SOT-23-5 Thin (TSOT-23-5) package — 5 pins, 0.95 mm pitch, 2.9 mm × 1.6 mm body — the footprint is compact enough for space-constrained portable designs but demands careful solder-paste stencil design to avoid bridging on the small pads.