Fixed 10V rail — what the dropout and PSRR tell you
The LM2940IMPX-10/NOPB is a fixed 10V positive LDO from TI's LM2940 family, delivering 1A continuous with a maximum dropout of 1V at full load. That 1V headroom means the input rail must stay above 11V (plus ripple) to maintain regulation — a common gotcha when reusing a 12V bus that sags under load. PSRR is 63dB at 120Hz, which is the 2x line-frequency ripple rejection figure. For a 12V input with 100 mVpp of 120Hz ripple, the output sees roughly 70 µVpp — clean enough for most analog front-ends, but if you need better rejection above 1 kHz, this part's PSRR rolls off and a post-filter stage may be needed.
Protection set and quiescent current
Protection covers over-current, over-temperature, reverse polarity, and short circuit — all on-chip. That saves a Schottky on the input and a PTC on the output in many designs. Quiescent current is 10 mA typical; supply max is 15 mA, so the regulator's own consumption is non-trivial in battery-powered gear but fine for a 10V rail in industrial or automotive-adjacent systems.