LM386
Public Unreviewedby adom
TI mono low-voltage audio power amp, DIP-8. Gain 20-200, drives 8 ohm, 4-12 V. Datasheet-verified.
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markdownLM386
Texas Instruments · Mono audio power amplifier · PDIP-8
A mono low-voltage audio power amplifier that drives a small 8 ohm speaker directly, in a DIP-8, the default for hobby audio and intercoms. Its voltage gain is internally fixed at 20, and a capacitor (or RC) across the gain pins (1 and 8) raises it up to 200 without extra parts. It runs from 4 to 12 V, draws only a few milliamps quiescent, and keeps the output biased at half-supply so a single output capacitor couples the speaker. Add a volume pot on the input and a 250 uF output cap and it is a complete amplifier.
Pinout
| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | GAIN | passive | Gain-setting pin (feedback network tap). Left open, an internal 1.35 kΩ resistor sets gain to 20 (26 dB). Placing a capacitor from pin 1 to pin 8 bypasses the 1.35 kΩ and raises gain to 200 (46 dB); a series R+C between pins 1 and 8 sets any gain 20-200. |
| 2 | -INPUT | input | Inverting audio input. Ground-referenced; internal 50 kΩ resistor to ground biases the input. Typical input bias current 250 nA; input resistance 50 kΩ. Maximum analog input voltage ±0.4 V. |
| 3 | +INPUT | input | Noninverting audio input. Ground-referenced; internal 50 kΩ resistor to ground biases the input. Typical input bias current 250 nA; input resistance 50 kΩ. Maximum analog input voltage ±0.4 V. |
| 4 | GND | power_in | Ground reference for the amplifier. All input signals and the internal bias network are referenced to this pin. |
| 5 | VOUT | output | Class-AB audio output. Self-centers at approximately VS/2 at quiescence. Drives 4-32 Ω speaker loads; typical output power 325 mW (VS = 6 V, RL = 8 Ω) up to 1 W (VS = 16 V, RL = 32 Ω, LM386N-4). Typical output should be AC-coupled to the load via a large series capacitor. |
| 6 | VS | power_in | Positive supply voltage. Recommended 4-12 V (LM386N-1/-3/M-1/MX-1/MM-1) or 5-18 V (LM386N-4). Absolute maximum 15 V (or 22 V for LM386N-4). Quiescent current ~4 mA. Bypass locally with a 0.05 µF decoupling cap for stability. |
| 7 | BYPASS | passive | Internal bias-network bypass node. Connect a bypass capacitor (typ. 10 µF) from this pin to ground to improve power-supply rejection (PSRR increases from ~10 dB with no cap to ~50 dB with 10 µF at 1 kHz). May be left open if PSRR is not critical. |
| 8 | GAIN | passive | Second gain-setting pin. Paired with pin 1: an external capacitor (optionally in series with a resistor) between pins 1 and 8 bypasses the internal 1.35 kΩ feedback resistor, raising the closed-loop gain from 20 up to 200. |
Key specifications
| Parameter | Value |
|---|---|
| Type | Mono audio power amplifier |
| Voltage gain | 20 (default) to 200 (via pins 1/8) |
| Output power | ~325 mW into 8 Ω at 6 V |
| Load | 8 Ω speaker (direct) |
| Supply voltage | 4-12 V |
| Quiescent current | ~4 mA |
| Input | ground-referenced |
| Package | PDIP-8 |
Ordering variants
Same part, different packaging or reel option.
LM386N-1 (PDIP-8)LM386N-4 (PDIP-8, higher supply)
CAD (KiCad official)
- Symbol:
Amplifier_Audio:LM386 - Footprint:
Package_DIP:DIP-8_W7.62mm - 3D model: DIP-8 (KiCad packages3D)
Provenance
Data extracted from the manufacturer datasheet, not a distributor listing:
- Datasheet: Texas Instruments datasheet (34 pp, sha256
b6019669384baef7, retrieved 2026-08-17, tier: manufacturer) - Extractor:
ds2sf(Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate. - CAD: KiCad official libraries (CC-BY-SA 4.0).