0.9 V rail from a 5-DSBGA package
The Texas Instruments TPS72009YZUT is a single-output, positive linear regulator delivering a fixed 0.9 V at up to 350 mA. It comes in a 5-DSBGA package (0.96 x 1.33 mm).
PSRR and quiescent current — the noise-vs-battery tradeoff
PSRR starts at 85 dB at 10 Hz and rolls off to 50 dB at 1 MHz. Quiescent current is 38 µA.
Protection and temperature range
On-chip protection includes over-current, over-temperature, and under-voltage lockout (UVLO). The enable pin lets the system power-cycle the rail without a separate load switch.