The Texas Instruments TPS61031PWPRG4 is a step-up (boost) DC-DC converter with a fixed 3.3V output, designed to generate a regulated 3.3V rail from a lower input voltage source such as a single Li-ion battery or USB power. Its input range spans 1.8V to 5.5V, meaning it can operate from a Li-ion cell down to its end-of-discharge voltage of roughly 2.7V and still hold the output steady, while also handling a 5V USB bus input without issue.
3.6A switch current — sizing the output load
The internal switch is rated for 3.6A, which translates to a practical continuous output current of roughly 2A at 3.3V from a 3.6V input, before hitting the switch current limit or thermal constraints in the 16-HTSSOP package. The switching frequency is fixed at 600kHz, a common choice that balances inductor size against switching losses — a 4.7 µH to 10 µH inductor typically works for most 3.3V output designs at this frequency.