Active 1A LDO with reset output — what the ratings mean for your rail
The Maxim MAX1793EUE33+ is a positive-output LDO regulator delivering 1A continuous current with a maximum dropout voltage of 0.35V at full load. The output is configurable as adjustable (down to 1.25V) or fixed at 3.3V, selected by the part variant. It includes an Enable pin for shutdown control and a Reset output for power-good sequencing — useful for MCU supply monitoring. The 16-TSSOP package with exposed pad (16-TSSOP-EP) helps pull heat into the PCB copper plane; that thermal pad needs a via stitch under the part to keep junction temperature under control above 500 mA continuous. Operating temperature covers -40°C to 85°C, suiting industrial control, outdoor telecom, and factory automation environments.
Dropout voltage at 1A — headroom planning
The 0.35V dropout at 1A is the worst-case figure across temperature. For a 3.3V output rail, the input must stay above 3.65V to maintain regulation at full load. That leaves a slim margin if the input comes from a 3.6V battery or a 3.3V rail with a diode-OR — the part will drop out before the battery is fully drained. Plan the input rail at 4.0V or higher for reliable regulation through the full load and temperature range.
Protection and control features
Built-in over-current, over-temperature, and short-circuit protection cover the usual fault cases. The Reset output asserts low when the output falls out of regulation — a clean way to hold a microcontroller in reset during power-up or brownout without an external supervisor IC. Quiescent current is 200 µA typical, which is moderate for a 1A LDO; not a micropower part, but acceptable for always-on rails that see intermittent load.
Package and mounting — thermal pad handling
The 16-TSSOP-EP package is surface-mount with an exposed pad on the bottom. The pad is the main thermal path — without a solid copper pour and at least four thermal vias under the pad, the junction temperature will exceed the 85°C ambient rating at currents above 600 mA. The part ships in Tube (not Tape & Reel), so plan for manual or tube-fed pick-and-place.