MC34119, TDA2822, or PAM8403 — Which Small Audio Amp IC Should You Use?

What the Three Classes Actually Are

Three amplifier classes dominate small audio: voice-band differential, stereo class-AB, and class-D. Each was built for a different product, and the datasheet tells you which.

The MC34119 is a speakerphone part that happens to be an amplifier. The TDA2822 is the 1980s stereo workhorse that never died. The PAM8403 is what the 1980s would have built if class-D were cheap.

A Three-Question Decision Tree

Three questions settle the choice before you look at a pinout: voice or music? mute or always-on? battery or wall?

One note from the bench: the decision tree looks obvious on paper, but in our experience (2025–2026) the most common mis-pick is mute — designs that need a logic-controlled silence end up on a part without one, then bolt on a transistor switch. The MC34119's CD pin exists exactly for that.

The Power Reality Check

Datasheet power figures hide two traps: the package and the load impedance. Both change what a "1W" part actually delivers.

When NOT to Use Any of These

Three situations where all three parts are the wrong answer — and what to reach for instead.

The "cheap three" are for products that make sound, not products that make audiophile sound. A doorbell, a toy, an intercom, a radio — those are the home turf. The moment a BOM says "hi-fi" or "car," these parts are out of their depth.

Frequently Asked Questions

Q1: Which of the three is cheapest?

A: The TDA2822 is usually the cheapest, but they're all within pennies. At volume, the TDA2822 and PAM8403 trade places depending on the week; the MC34119 is rarely the cheapest. Price is the worst selection criterion here — a wrong topology costs more in rework than any price difference.

Q2: Can I use the MC34119 for music?

A: Technically yes; practically no. Its gain shaping and bandwidth are tuned for the 300Hz–3.4kHz voice band. Music plays, but it sounds like a phone call — because that's what the part is. Use the TDA2822 or PAM8403 for music.

Q3: Do I need an LC filter with the PAM8403?

A: No — it's filterless by design. The PAM8403 drives the speaker directly with a spread-spectrum PWM output. Keep the speaker wires short (under ~10cm) and it passes EMC without output inductors, which is why it dominates battery designs.

Q4: What's the biggest amplifier mistake in small products?

A: Picking the amp before defining the speaker load. From our experience (2025–2026), boards fail or sound weak because the amp was chosen for price while the speaker ended up at an impedance the part wasn't rated for. Define load impedance and target power first; the part number follows.

Q5: Can I bridge the MC34119 for more power?

A: No — it's already differential. The outputs swing in opposition by design, which is the bridge principle built in. There's no further bridging possible; to get more power you move to the TDA2822 bridged or class-D.

Q6: Which one should I stock first?

A: All three — they cover three different product families. If you stock only one: the TDA2822 (covers stereo and bridged voice at the lowest cost). Add the MC34119 for speakerphone products and the PAM8403 for battery designs, and your bench covers the whole small-audio space.