Noise-sensitive rail regulator in a 1x1 mm footprint
The LP3991TLX-1.5/NOPB is a fixed 1.5 V output LDO from Texas Instruments, delivering up to 300 mA with a maximum dropout voltage of 0.16 V at full load — the headroom between the input rail and 1.5 V must stay above 160 mV across the load range, or the output falls out of regulation. With a PSRR of 65 dB at 1 kHz, this regulator attenuates upstream ripple by a factor of roughly 1800 — suitable for powering analog front-ends, ADC/DAC reference rails, or audio codecs where supply noise degrades signal integrity.
Housed in a 4-bump DSBGA measuring 1x1 mm (supplier device package 4-DSBGA), the LP3991TLX-1.5/NOPB occupies minimal PCB area — the 0.5 mm pitch demands careful solder-paste stencil design and X-ray inspection to confirm bump wetting. Surface-mount assembly with tape-and-reel or cut-tape packaging options; the enable pin allows the regulator to be gated by a system-level power-good or sleep signal, reducing quiescent draw to near zero when the load is idle.
Protection and compliance
Built-in over-temperature and short-circuit protection prevent damage under fault conditions — the regulator enters thermal shutdown if the die exceeds the safe limit and recovers automatically when it cools. Texas Instruments lists this part as Active in production with ROHS3 compliance — no end-of-life risk for ongoing designs, and the green finish meets current regulatory requirements for most markets.