The TPS611781RNWR is a Texas Instruments step-up (boost) converter with a 10A integrated switch and a fixed 2.2 MHz switching frequency. Synchronous rectification is built in — the low-side FET replaces the usual catch diode, which cuts the forward-drop loss at high current and saves a Schottky from the BOM. The trade-off is that the part needs a bootstrap capacitor and careful dead-time control, but TI handles that internally.
Input range, output range, and the adjustable feedback loop
Input voltage spans 2.7V to 20V, which covers single-cell Li-ion up to a 12V or 15V rail. The adjustable output goes from a 4.5V minimum up to 20V — set by a resistor divider on the FB pin. The 4.5V floor means you cannot use this part for a 3.3V rail; it is designed for 5V, 9V, 12V, or 15V intermediate buses. The single-output positive configuration is straightforward: one feedback resistor pair, one inductor, input and output caps. No external compensation network — the internal loop is stable over the full range as long as the output cap ESR stays within the datasheet guidelines.
Package, temperature grade, and sourcing posture
No official second-source or direct replacement is listed; the base product number TPS611781 covers the family.