Regulator with a low quiescent draw and dual-mode output
The Maxim MAX603ESA+ is a single-output positive LDO regulator that delivers up to 500 mA from an input rail as high as 11.5 V. Its standout feature for always-on or battery-backed rails is the 35 µA quiescent current — that is the current the regulator burns just to stay alive, regardless of load. For a microcontroller or sensor node that spends most of its time in sleep, that 35 µA Iq is the difference between a battery that lasts a season and one that lasts a year. The output can be set as adjustable from 1.25 V up to 11 V, or strapped for a fixed 5 V output using the same pin configuration. Dropout voltage is 0.55 V at the full 500 mA load, so the input must stay at least that far above the output to maintain regulation. Protection circuits cover over-current, over-temperature, and reverse polarity on the input. The enable pin lets a system controller gate the regulator on and off, which is how you drop the load current to near zero in a sleep state. The part is rated across the industrial temperature range of -40°C to 85°C, so it fits outdoor telecom, factory-floor sensors, and engine-bay electronics that see thermal cycling.
Package and footprint
Housed in an 8-pin SOIC package (3.90 mm body width), the MAX603ESA+ is a surface-mount part that reflows on a standard SOIC-8 land pattern. The supplier device package is listed as 8-SOIC, and the shipping form is Tube — not Tape & Reel, so if your pick-and-place line expects reels, factor in a tube-to-reel transfer or order the tape-compatible variant.
Lifecycle and sourcing
ROHS3 compliant, so it passes the EU material restrictions without an exemption expiry to track.