IC LM 380 is a
Power audio amplifier
The LM380 is a fixed-gain audio power amplifier — option 3. It delivers about 2.5 W into 8 Ω from a single supply of 12 to 22 V, with an internally set voltage gain of 50 (34 dB) and an output that self-centres at half the supply so that no coupling capacitor is needed at its input side.
| Parameter | Value |
|---|---|
| Output power | 2.5 W into 8 Ω |
| Voltage gain | 50, fixed internally |
| Supply | Single, 12 – 22 V |
| Output quiescent level | VCC/2, set internally |
| Package | 14-pin DIP with heat-sink pins |
Why the gain is fixed at 50. The internal feedback network is on-chip, which removes the external components a discrete design would need and guarantees stability — at the cost of flexibility. Its middle pins are bonded to the die's substrate so that the printed-circuit copper acts as the heat sink, which is what allows a plastic DIP to dissipate several watts.
Why the other options are wrong — and what those part numbers would be.
| Function | Typical IC |
|---|---|
| Voltage regulator | LM78xx series, LM317 |
| Rectifier | Not an IC function — discrete diodes or a bridge |
| Audio power amplifier | LM380, LM386, TDA2003 |
| Comparator / Schmitt trigger | LM311, LM339, 74LS14 |
The number is easy to confuse with the LM386, its smaller cousin: 8-pin, 0.5 W, gain 20 by default but settable to 200 by bridging pins 1 and 8 with a capacitor. Both are the standard "one-chip loudspeaker driver" of hobby and instrument electronics.
The classification worth carrying away is that of the four options only two describe things an integrated circuit does at all — regulation and amplification — and the "LM" prefix with a three-digit number in the 300s belongs to National Semiconductor's linear range, of which the LM380 is the audio member.
Hence, the LM380 is a power audio amplifier.
Similar Questions
Consider the following ICs :
1. LM 78 05
2. LM 78 15
3. LM 78 12The correct sequence of the output noise voltage (at 25 °C and for an operating frequency range of 10 Hz ≤ f ≤ 100 KHz) in decreasing order is given by
Assertion (A) : The series pass transistor in a regulator is in class A mode.
Reason (R) : Class A is a switching mode and yields high efficiency.
Important Questions from Power Amplifiers and 555 Timer and Voltage Regulators
In VCO IC 566, the value of charging & discharging is dependent on the voltage applied at ________.
Which among the following are the features of push-pull amplifier?
(i) Noise rejection
(ii) Can give efficiency of more than 50
(iii) Output may have cross over distortion
(iv) Output may have harmonic distortion
Power amplifiers generally use transformer coupling because transformer permits
In a single tuned capacitance coupled amplifier, the frequency response depends on
If a high degree of selectivity is desired, then double tuned circuit should have
