Fixed 2.5 V rail at 800 mA — the BOM anchor
The LD1117V25C is a positive fixed-output low-dropout regulator from STMicroelectronics, delivering a regulated 2.5 V at up to 800 mA. The single-output LDO is designed for through-hole mounting in a TO-220-3 package, making it a straightforward drop-in for existing board layouts that need a clean 2.5 V rail from a 15 V maximum input.
Dropout voltage and protection — the real-world margins
Maximum dropout voltage is 1.3 V at the full 800 mA load. Quiescent current is 10 mA.
Ripple rejection at line frequency
Power-supply rejection ratio is 75 dB at 120 Hz.
Temperature grade and package — industrial deployment
The TO-220-3 package with a metal tab can be bolted to a heatsink or chassis for thermal management; junction-to-case thermal resistance is low enough that 800 mA at high dropout may still require a heatsink, depending on ambient airflow.
STMicroelectronics has classified the LD1117V25C as Obsolete. For BOM lines that still specify this exact code, the only supply channel is the surplus and broker market. The TO-220-3 package and the fixed 2.5 V output are the two non-negotiable fit criteria for any replacement candidate.