Regulator fit for 5V or adjustable rails
The onsemi LP2951CDR2G is a positive LDO regulator delivering up to 100 mA from an input rail that can reach 30 V. The output can be set as a fixed 5 V rail or adjusted from a 1.235 V reference — the same device covers both architectures, reducing BOM line count when a design uses multiple output voltages across variants.
Dropout and headroom at full load
Maximum dropout voltage is 0.45 V at 100 mA output. For a 5 V fixed output, a 5.5 V input rail at the low end of tolerance still holds 50 mV of headroom — marginal but workable if the input capacitor is sized for the transient dip. Quiescent current is 120 µA typical, rising to 12 mA max under full supply current. The 120 µA Iq matters for always-on or battery-backed rails where the regulator's own draw cuts into standby time. Over-current and over-temperature protection are built in, so the part survives a sustained short or a high-ambient stall without external crowbar circuitry.