2.5W mono into 8Ω — the headline fit decision
The LM380N-8/NOPB delivers 2.5W into an 8Ω load from a single supply rail — this is the output power that governs the loudspeaker selection and the enclosure's acoustic budget. For a desktop speaker or intercom, 2.5W is enough for moderate listening levels; for a portable PA or outdoor announcement system, it will clip before reaching room-filling volume. The supply range spans 10V to 22V, so it runs off a common 12V or 18V DC wall adapter without a separate regulator. At the low end, output swing is limited; at 22V the device reaches its maximum undistorted swing into the rated load.
Class AB operation means the output stage biases into a low-current conduction region, avoiding the crossover distortion of Class B while keeping quiescent dissipation lower than a pure Class A stage. For a 2.5W output, expect a heatsink on the 8-DIP package if the ambient exceeds 50°C — the thermal resistance of the plastic DIP without a copper plane is around 100°C/W junction-to-ambient. Built-in short-circuit and thermal protection eliminate the need for an external current-limit resistor or a thermal cutoff. The thermal shutdown threshold is typically 150°C junction; the amplifier recovers automatically when the die cools, which is useful in a fault-tolerant design but means the load fault must be cleared before the part cycles back on. This part is not qualified for automotive or outdoor enclosures that see sub-zero startups or sustained heat above 70°C ambient.
8-DIP through-hole — board-fit and sourcing reality
The 8-pin DIP package (0.300-inch row spacing, 7.62 mm body width) is a legacy through-hole footprint. It is straightforward to hand-solder or wave-solder, but it occupies more board area than an equivalent SOIC-8 surface-mount amplifier. For a new design where board space is tight, consider the surface-mount variant LM380N-8/SO or a smaller Class D alternative; for a repair or a low-volume build, the DIP is easier to work with and swap. The LM380N-8/NOPB is the lead-free (NOPB) version of the original LM380N. The suffix confirms it is the same die in the same package, just with ROHS-compliant plating. If your BOM calls out the older LM380N, this part is a drop-in replacement — no board changes needed.