Fixed 5V rail for industrial and mixed-signal loads
Key protection features include over-current, over-temperature, and short-circuit shutdown — no under-voltage lockout, so the output follows the input during power-up ramps. An enable pin provides external on/off control for sequencing multiple rails.
Maximum dropout voltage is 0.22 V at 50 mA load. For a 5 V output, the input must stay above 5.22 V worst-case to maintain regulation. That 0.22 V floor is typical for a 50 mA LDO of this era — newer parts like the LP5907 achieve lower dropout at higher currents, but the LP2980's 16 V input maximum gives it headroom for unregulated supplies that sag under load. PSRR is 63 dB at 1 kHz, which attenuates a 1 Vpp ripple on the input to about 0.7 mVpp on the output at that frequency. At higher switching frequencies (100 kHz to 1 MHz) the rejection rolls off — if your design uses a switching regulator upstream and needs clean 5 V for an ADC or analog front-end, budget a post-filter or consider a newer LDO with higher bandwidth PSRR. That Iq is acceptable for always-on rails in battery-backed equipment but not competitive with modern ultra-low-Iq LDOs that draw under 10 µA. For a 50 mA load, the efficiency floor is about 98% at dropout — the quiescent loss dominates at light loads.
New designs should not target this part; existing BOM lines must be sourced through independent distribution or surplus channels. Date-code spread and packaging condition (sealed reels vs cut tape) vary by lot and are verified per order.
SOT-23-5 footprint and layout notes
The LP2980IM5X-5.0 is supplied in a SOT-23-5 package (also designated SC-74A, SOT-753). The 5-pin footprint is standard for this package family — 0.95 mm pitch, 2.9 mm body length. The output capacitor should be a 1 µF to 10 µF ceramic placed within 5 mm of the output pin for stability. This part is surface-mount only.