What this PMIC does for an energy-harvesting rail
The TPS65290ZBRHFT is a three-output converter IC from Texas Instruments, purpose-built for energy-harvesting applications. Its input range of 2.2V to 5V covers single-cell Li-ion, two-cell alkaline, or a small solar panel — the typical source in a remote sensor node.
The 2.2V to 5V input window means the part starts up cleanly from a nearly depleted Li-ion cell (3.0V nominal) and tolerates a fully charged one at 4.2V. Without that, the junction temperature rise at full output current will exceed the 85°C ambient ceiling. The datasheet layout recommendation on page 7 is the starting point.
For a design that may run for years in the field, this part does not carry single-source risk from an obsolescence standpoint.