The onsemi LP2950CDT-3.0 is a single-output, positive fixed LDO regulator delivering 3.0 V at up to 100 mA. It is built for applications where a clean, regulated 3.0 V rail is needed from a higher input — think sensor supplies, MCU analogue front-ends, or always-on standby rails in industrial and automotive gear.
Dropout and headroom — the 0.6 V margin
Maximum dropout voltage is 0.6 V at the full 100 mA load. That means the input must stay above 3.6 V to maintain regulation at full current; below that the output starts to track the input minus the dropout. For a 5 V rail feeding this LDO, there is 1.4 V of headroom — plenty. But if the input is a 3.7 V lithium cell near end-of-discharge, the margin disappears and the output droops. Budget the dropout against the worst-case input voltage in your system.
Protection features — over-current and over-temperature
Built-in over-current and over-temperature protection let the part survive a hard short or a stalled load without immediate destruction. The thermal shutdown kicks in when the junction exceeds the die temperature limit; once it cools, the regulator restarts. This is standard for industrial-grade LDOs and saves an external current-limit circuit.
Package and thermal — TO-252-3 (DPak)
The TO-252-3 (DPak) surface-mount package has a metal tab on the output pin that acts as the primary heat path. A 1-inch-square copper pour on the top layer with thermal vias to an internal plane is typical for this package class.
Sourcing an obsolete regulator
The LP2950CDT-3.0 is listed as obsolete. For BOM lines that still call out this exact code, supply is limited to surplus and broker-channel inventory — sealed reels or tube stock with date-code spreads typical of factory overruns and end-of-life buybacks.