The MAX1973EUB+ is a 1A continuous-output synchronous buck converter switching at 1.4 MHz. Input range spans 2.6 V to 5.5 V, covering single-cell Li-Ion (3.6 V nominal) and 5 V USB rails. The output is adjustable down to 0.75 V via an external resistor divider, with fixed presets at 1.8 V and 2.5 V — the 0.75 V floor suits core voltages for low-power MCUs and FPGAs. Internal synchronous rectifier eliminates the external Schottky diode, saving board space and bill-of-materials count. Efficiency peaks above 90 % at moderate loads; the 1.4 MHz switching frequency places the fundamental ripple above the audio band and keeps the output ripple low enough for most analog supplies.
10-uMAX package — rework and board-fit considerations
Housed in a 10-lead uMAX (also called uSOP), the package is 3.0 mm wide with 0.5 mm pitch — small enough for tight layouts but still hand-reworkable with a hot-air station. The exposed pad underneath is the thermal path; a via array under the pad to the ground plane keeps the junction temperature in check at full 1 A load. The lead frame is tin-plated; a no-clean flux and 350 °C hot air for 20–30 seconds lifts the part cleanly without lifting pads, provided the board has been pre-baked per J-STD-033 if moisture-sensitive.