5V fixed LDO — where the dropout and PSRR matter
The LM2931AZ50AP is a 5 V fixed-output low-dropout regulator from the LM2931 family, rated for 100 mA continuous output. Its 0.6 V maximum dropout at full load means the input rail can sag to 5.6 V before the output loses regulation — a tight headroom budget that suits battery-backed or lightly regulated supplies. Power supply rejection is 75 dB at 120 Hz, which filters the mains-frequency ripple from a rectified bulk supply or a switching pre-regulator. That PSRR figure, combined with the 1 mA quiescent current, makes this part a clean post-regulator choice for sensitive analog loads downstream of a noisy rail.
Temperature range and application envelope
The TO-92-3 through-hole package with formed leads is a straightforward hand-assembly or wave-solder fit for legacy boards and retrofit repairs. Protection features include current limit and thermal shutdown — the regulator survives a sustained output short or overload without secondary damage, which is a practical advantage in field-deployed equipment where a blown regulator means a service call.
The LM2931AZ50AP carries an obsolete product status.