0.8V minimum input — single-cell battery boost
The TPS61260DRVT is a synchronous boost regulator from Texas Instruments that starts from an input as low as 0.8 V and delivers an adjustable output between 1.8 V and 4 V. The 100 mA output ceiling keeps it squarely in the low-power domain; if your load pulls 150 mA peak, this part will current-limit or drop out, so size the load budget before layout.
2.5 MHz switching — small inductor, fast loop
The 2.5 MHz switching frequency lets you use a 1 µH to 2.2 µH inductor and a small ceramic output cap, which keeps the total solution footprint tight on a 6-WSON (2x2) package. The trade-off is that switching losses rise at light loads — expect efficiency to peak around 50–70 mA and taper above 80 mA.