Fixed 2.7 V rail for low-power analog and mixed-signal loads
The ADP3308ART-2.7-RL is a single-output LDO from the anyCAP® family, delivering a fixed 2.7 V at up to 50 mA from an input rail as high as 12 V. The 170 mV typical dropout at full load means the input must stay at least 170 mV above 2.7 V — a 3.0 V rail is sufficient, but a 3.3 V rail gives comfortable headroom for line transients. The Enable pin lets a GPIO or supervisor pull the output off, dropping the quiescent current from 300 µA to near zero — useful for sequenced power-up or sleep modes in battery-powered instruments.
Dropout, Iq, and protection — what the numbers mean for your rail budget
Dropout of 170 mV at 50 mA is tight enough for a 3.0 V input to 2.7 V output, but the spec is a maximum — at lower loads the dropout shrinks, so a 2.85 V rail (say, from a nearly-depleted Li-ion cell) still regulates cleanly as long as the load is well below 50 mA. Quiescent current of 300 µA is moderate — not the sub-µA territory of a dedicated ultra-low-Iq LDO, but acceptable for always-on peripherals drawing a few mA. The max supply current of 1.4 mA includes the internal bias and pass-element drive; the actual efficiency at 50 mA output is roughly 2.7 V / 3.3 V = 82 %, minus the 1.4 mA overhead. Over-current and over-temperature protection are built in — the LDO folds back current during a hard short and shuts down if the die exceeds the thermal limit. No external current-limit resistor or thermal shutdown circuit is needed.
SOT-23-5 footprint and temperature grade
The part is supplied in a SOT-23-5 package (SC-74A, SOT-753 footprint), surface-mount, with a Bulk shipping medium. The five pins are IN, OUT, GND, EN, and the NC tab — the Enable pin is active-high; leave it tied to IN if not used. Operating temperature range is -20°C to 85°C (ambient), which covers most indoor and telecom-grade equipment but not extended industrial or automotive under-hood environments.