Step-up from a single cell to 3.3V or 5V
The MAX756ESA+: Switching at 500 kHz, the converter keeps the inductor small enough for a compact layout, though the absence of a synchronous rectifier means an external Schottky diode is needed to maintain efficiency at higher output currents.
Input range and thermal envelope
With a maximum input of 7 V, the part tolerates a 2-cell Li-ion or a regulated 5 V bus, but the 0.7 V minimum lets it harvest energy from a nearly depleted cell — useful in battery-backed instrumentation where the rail must hold until the last millivolt.