Obsolete — sourcing the LM2931ADT50RY
The LM2931ADT50RY is listed as obsolete.
5 V fixed rail, 100 mA — what it drives
This is a single-output positive LDO delivering a fixed 5 V at up to 100 mA. The 0.6 V maximum dropout at full load means it holds regulation with an input as low as 5.6 V — useful in automotive 12 V or 24 V systems where the battery can sag during cranking. Quiescent current is 1 mA typical, with a maximum supply current of 30 mA. The 75 dB PSRR at 120 Hz is the spec that matters for alternator whine rejection — it filters the 120 Hz ripple from a full-wave rectified alternator output before it reaches sensitive loads like sensor supplies or microcontroller analogue rails.
Automotive-grade build
The DPAK (TO-252-3) surface-mount package with exposed tab helps conduct heat to the board copper pour. Protection features include current limit and thermal shutdown, which guard against output shorts and overloads in the harsh automotive electrical environment.