SPICE subcircuitLM386M-1lm386
LM386 (audio amplifier)
Power amplifier for 4–8 Ω speakers, 4–12 V. Gain 20 (pins 1/8 open) to 200 (10 µF between 1 and 8), output biased to VS/2, inputs 50 kΩ to ground. Macromodel: gain, operating point, swing limit ≈ 0.4 V below the rails, quiescent current 4 mA; no frequency-response or distortion details.
Key data
- Category
- ICs
- Simulation model
- SPICE subcircuit
- Manufacturer part number
- LM386M-1
- Reference prefix
- U
- Pins
- 8
- Land pattern
- SOIC-8_3.9x4.9mm_P1.27mm
Simulation model
The part is a small SPICE netlist (below), solved by the analog engine together with the rest of the circuit. Pin ids are the node names, {braces} are parameters.
SPICE netlist
Ri1 3 4 50k
Ri2 2 4 50k
E1 a 4 3 2 1
Re a 1 150
Rg 1 8 1.35k
H1 o m 8 4 30k
E2 m 4 6 4 0.5
Ro o 5 0.5
E3 hi 4 6 4 1
Vhi hi lim 0.9
D1 5 lim D386
Vlo lo 4 0.3
D2 lo 5 D386
Rq 6 4 2.25k
Rb1 6 7 15k
Rb2 7 4 15k.model D386 D(IS=1e-12 N=1 RS=0.05)Pins 8
| Pin | Name | Use |
|---|---|---|
| 3 | +INInput pin | Non-inverting input: audio in through a volume pot |
| 2 | −INInput pin | Inverting input: usually to GND |
| 1 | GAINAnalog pin | Gain set: 10 µF between pins 1 and 8 for gain 200, open for gain 20 |
| 8 | GAINAnalog pin | Gain set: see pin 1 |
| 5 | OUTOutput pin | Output: 250 µF to the speaker, Zobel network 10 Ω + 47 nF to GND |
| 7 | BYPAnalog pin | Bypass: 10 µF to GND for better supply rejection |
| 6 | VSSupply pin | Supply 4–12 V: 100 nF + 100 µF to GND |
| 4 | GNDGround pin | Ground |
PCB
Verified land pattern
SOIC-8_3.9x4.9mm_P1.27mm