What the MAX8840ELT18+T delivers
The MAX8840ELT18+T is a fixed-output linear regulator from Analog Devices that holds a 1.8V rail at up to 150mA. It comes in a 6-uDFN package (1.5x1 mm footprint) — small enough for space-constrained PCBs in portable or embedded designs. The enable pin lets you gate the output for power sequencing or sleep modes, and the quiescent current sits at 90 µA, which keeps the battery drain low in always-on applications.
PSRR — where it cleans up and where it doesn't
Power-supply rejection ratio is 78 dB at 1 kHz, dropping to 54 dB at 100 kHz. That means this LDO knocks down low-frequency ripple from a switching pre-regulator or a noisy digital rail, but above 100 kHz the attenuation fades. If your load is a sensitive RF front-end or a precision analog chain running at several megahertz, you'll want to pair this with a post-filter or pick a higher-PSRR part. For audio-frequency noise on a 1.8V sensor supply, it's fine.