5V rail for harsh environments — 1A LDO with 1V dropout
The Texas Instruments LM2940T-5.0 is a fixed 5V output, 1A low-dropout regulator in a TO-220-3 through-hole package. It delivers up to 1A with a maximum dropout voltage of 1V at full load, making it suitable for post-switcher clean-up or battery-powered rails where input-to-output headroom is tight.
PSRR and protection — what the ratings mean
The 64dB PSRR at 120Hz tells the designer how much 100/120Hz ripple from a rectified AC input or a switching pre-regulator gets attenuated. At 64dB, a 1Vpp ripple on the input drops to about 0.6 mVpp on the output — enough for most analog and logic supplies, though a 5V ADC reference might need a second stage. On-chip protection includes over-current, over-temperature, reverse polarity, and short-circuit shutdown. The reverse polarity clamp means the regulator survives a reversed battery connection without external Schottky diodes — a real advantage in automotive and battery-backed systems.
It remains available for existing production runs and repairs, but TI advises against using it in new projects.