Audio Amplifier IC
Integrated Circuit
A power amplifier on a chip: signal in, speaker out, minimal external parts. From the venerable LM386 breadboard companion to Class-D chips that drive real watts off a battery without a heatsink.
Schematic symbol
Operational amplifier
How audio amplifier ic appears in a circuit diagram.
Types & variants
Key specs
Output power
WInto a stated load and supply: LM386 ~0.5 W/8 Ω, PAM8403 3 W/4 Ω, TPA3116 2×50 W/4 Ω at 24 V. Real usable power is less than headline figures.
Supply range
VLM386: 4–12 V single rail; TDA2030: ±6–18 V split; TPA3116: 4.5–26 V. Match your available rail first.
Efficiency / class
%Class-AB wastes ~50% as heat (needs heatsinking); Class-D hits 85–92% (battery life, no heatsink at low power).
THD+N
%Distortion at rated power — <0.1% is clean; small chips near clipping reach several percent.
Gain
dBFixed or pin-set: LM386 20–200 V/V via pins 1–8; Class-D chips typically 20–36 dB selectable.
Speaker load
Ω4 or 8 Ω typical; bridged (BTL) outputs must NOT have either speaker wire grounded.
Markings
Standard IC part numbers on DIP-8 (LM386), Pentawatt TO-220-5 (TDA2030), TSSOP/QFN (Class-D). Modules print the chip name and speaker/power terminals.
Standard values
The hobby ladder: LM386 (breadboard audio), PAM8403 module (5 V USB projects), TDA2030/2050 (classic 10–20 W builds), TPA3116D2 modules (serious cheap power), MAX98357 (I2S digital-in for ESP32 streaming).
How to choose
1) Battery/USB project → Class-D (PAM8403/TPA3116). 2) Learning/lo-fi breadboard → LM386. 3) Hi-fi from a chip → LM3886/TDA7294 with a proper split supply. 4) Digital audio from an MCU → I2S DAC-amp (MAX98357). 5) Check BTL vs single-ended before wiring grounds, and add the Zobel/bootstrap parts the datasheet shows — they're not optional decorations.
Pinout & package
Typical: IN+, IN−, gain-set pins, VCC/GND, OUT (or OUT+/OUT− bridged). Class-AB power tabs bolt to heatsinks (tab often at −VE or GND potential — check). Modules: solder pads for supply, L/R in, speaker pairs.
Example circuits
- LM386 'big muff' amp: 10 µF gain cap for ×200, speaker via 220 µF
- PAM8403 + potentiometer as a two-component desktop speaker driver
- TPA3116 stereo board + 19 V laptop brick = bookshelf amplifier
- ESP32 → MAX98357 I2S → speaker: an internet radio in three parts
Common failures
Overheating Class-AB without a heatsink (thermal shutdown or death), motorboating/oscillation from missing supply decoupling, blown outputs from shorted speaker wires, hiss from gain set too high, and grounding one side of a BTL output (instant damage).
How to test
Finger-on-input test: touching the input should produce hum from the speaker — proves the chain amplifies. Feed a 1 kHz sine and scope the output for clean amplitude until clipping. Check DC offset across the speaker (<50 mV single-ended); high offset means a damaged chip.
Substitutes
Same-class chips substitute if supply, load and pinout allow (TDA2030/2040/2050 form an upgrade family). Discrete transistor stages replace ICs educationally. For new designs, Class-D modules replace nearly everything below hi-fi tier.