Dual-output LDO for noise-sensitive rails
The Texas Instruments TPS728330185DRVT is a fixed-output, positive-voltage LDO regulator that delivers a 3.3 V rail and a 1.85 V rail from a single input, rated for 200 mA total output.
PSRR — what the 65 dB to 40 dB roll-off means for your rail
The PSRR of 65 dB at 100 Hz dropping to 40 dB at 100 kHz tells you how much ripple from a switching pre-regulator this LDO can reject. At 100 kHz you get 40 dB of rejection, which attenuates a 100 mVpp ripple to about 1 mVpp. The 80 µA quiescent current keeps the overhead low for always-on subsystems.
Protection and control
Built-in over-current, over-temperature, and under-voltage lockout (UVLO) protect the load and the regulator. The enable pin lets you sequence the rail on/off with a logic signal, which is useful for power-sequencing in multi-rail designs.