Fixed 5V rail from a 3.2V–5.5V input — the Li-ion boost sweet spot
The TPS61241YFFR is a step-up (boost) converter from Texas Instruments that delivers a fixed 5V output from a single-cell Li-ion battery or 3.3V rail. The internal switch is rated for 600 mA peak current, which sets the practical output current ceiling — at 5V out from a 3.2V input, you get roughly 350–400 mA continuous before the switch current limit kicks in. That makes it a fit for powering a 5V USB peripheral, a small sensor module, or a wireless MCU from a battery that sags to 3.2V at end of discharge.
3.5 MHz switching — small inductor, low ripple
6-DSBGA — the scorch mark fits under a fingernail
The 6-DSBGA package is a wafer-level chip-scale package. There is no mould compound — the die backside is exposed, so the solder joints are the only mechanical attachment.