Fixed 8 V rail for noise-sensitive loads
The Texas Instruments LM2940S-8.0/NOPB is a fixed-output positive LDO regulator delivering 1 A at 8 V with a maximum dropout of 1 V at full load. The protection block covers over-current, over-temperature, reverse polarity, and short circuit — the four failure modes that kill a linear regulator in an automotive or industrial 24 V environment.
Dropout and headroom planning
The 1 V maximum dropout at 1 A sets the minimum input-to-output differential. For an 8 V output rail, the input must stay above 9 V worst-case — a 12 V nominal bus with 3 V of ripple or sag still clears the headroom. Below that the regulator drops out and the output follows the input minus the pass element's drop, losing regulation. Quiescent current is 10 mA typical, rising to 15 mA maximum at full supply. That Iq is higher than a modern CMOS LDO's microamp-level draw, but acceptable for a 1 A-rated bipolar design where the load current dominates the thermal budget.
At 1 A with a 2 V input-to-output differential, the power dissipation is 2 W — the tab copper area and airflow set the junction temperature, not the package itself.