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PAM8302

A 2.5 W mono class-D amplifier breakout with differential inputs, a volume trimmer and a shutdown pin, for one 4 to 8 ohm speaker.

  • Supply voltage2.0 V to 5.5 V
  • Absolute maximum supply6.0 V
  • Output power at 5 V2.5 W into 4 ohm, 1.5 W into 8 ohm at 10 % THD+N (typical)
  • Gain23.5 dB typical (Adafruit board: 24 dB default, trimmer turns it down)
Build with it in TinkeredDatasheet
PAM8302, A 2.5 W mono class-D amplifier breakout with differential inputs, a volume trimmer and a shutdown pin, for one 4 to 8 ohm speaker.
In short

The PAM8302 is a mono class-D amplifier that delivers 2.5 W into 4 ohm or 1.5 W into 8 ohm at 5 V and 10 % THD, from a 2.0 V to 5.5 V supply (Diodes PAM8302A datasheet DS41333, p. 3). Adafruit's breakout puts 1.0 µF capacitors on its A+ and A- inputs and a volume trimmer down from the default 24 dB gain; with a single-ended source you tie A- to ground (Adafruit #2130 product page). The speaker goes between the + and - terminals, never to ground.

The PAM8302A is the mono sibling of the PAM8403: a filterless class-D amplifier with 85 % to 88 % peak efficiency, 4 mA quiescent current and under 1 µA in shutdown (Diodes datasheet, p. 3). It suits battery and USB projects that need one loud speaker: alarms, talking toys, doorbells and voice prompts.

Adafruit's breakout makes the inputs fully differential through two 1.0 µF capacitors, adds a trimmer that turns the volume down from the 24 dB default, and brings out SD, the active-low shutdown (Adafruit #2130). Its output is bridge-tied, switching at about 250 kHz, so the speaker connects straight across the output terminals.

Because the output is a high-frequency PWM rather than an audio waveform referenced to ground, it cannot feed another amplifier or a line input. Treat it as the last stage before the speaker.

PAM8302 pinout

tinkered.ai/components/pam8302PAM8302A_PLUSAudio in +A_MINUSAudio in -SDShutdown (active low)GNDGroundVINPowerOUT_PLUSSpeakerOUT_MINUSSpeaker
PinFunctionType
A_PLUSAudio in +input
A_MINUSAudio in -input
SDShutdown (active low)High above 1.2 Vinput
GNDGndpower in
VINVin2.0 V to 5.5 Vpower in
OUT_PLUSSpeakeroutput
OUT_MINUSSpeakeroutput

How to wire the PAM8302

Pin by pin, for the board you have.

PAM8302Arduino UnoNote
VIN5V
GNDGND
A_PLUSD8Through 10 kOhm, with 1 kOhm from A+ to GND, to bring the 5 V square wave to line level.
A_MINUSGND
SDD7HIGH plays, LOW shuts the amplifier down.
OUT_PLUSSpeaker +
OUT_MINUSSpeaker -
  • Never connect the speaker's - terminal or either output to GND.
  • At full volume into 4 ohm the amplifier draws several hundred milliamps from 5V; turn the trimmer down if the Uno resets.
Design this circuit on an Arduino Uno

PAM8302 code

Every example here compiles for its board.

No library needed
// PAM8302 on Arduino Uno: wiring and a free simulation at https://www.tinkered.ai/components/pam8302
// PAM8302 on an Arduino Uno: tone on D8 (10k/1k divider) into A+, A- to GND, SD on D7.
const int AUDIO_PIN = 8;
const int SD_PIN = 7;

void beep(int freq, int ms) {
  tone(AUDIO_PIN, freq, ms);
  delay(ms + 50);
}

void setup() {
  Serial.begin(115200);
  pinMode(SD_PIN, OUTPUT);
  digitalWrite(SD_PIN, LOW);  // off while the supply settles
  delay(10);
  digitalWrite(SD_PIN, HIGH); // amplifier on
  Serial.println("PAM8302 ready");
}

void loop() {
  Serial.println("Siren");
  for (int f = 600; f <= 1200; f += 20) { tone(AUDIO_PIN, f); delay(10); }
  for (int f = 1200; f >= 600; f -= 20) { tone(AUDIO_PIN, f); delay(10); }
  noTone(AUDIO_PIN);
  Serial.println("Two beeps");
  beep(880, 150);
  beep(880, 150);
  digitalWrite(SD_PIN, LOW); // shut down between alerts: under 1 uA
  delay(2000);
  digitalWrite(SD_PIN, HIGH);
}
Compiled for arduino:avr:uno on 2026-10-30

Before you wire it

Do
  • Keep Vin between 2.0 V and 5.5 V (Diodes datasheet, p. 3).
  • Tie A- to GND when you feed a single-ended signal into A+ (Adafruit #2130).
  • Bring a GPIO's logic-level signal down to line level with a divider before A+; the default gain is about 24 dB.
  • Use a 4 ohm or higher speaker (Adafruit #2130).
  • Start with SD low and raise it about 10 ms after power-up to avoid a pop (datasheet, p. 8).
Don’t
  • Never connect either output terminal to ground or to another amplifier's input: it is a bridge-tied 250 kHz PWM output (Adafruit #2130).
  • Never exceed 6.0 V on Vin (datasheet, p. 2).
  • Never drive the inputs beyond the supply rails: -0.3 V to VDD + 0.3 V (datasheet, p. 2).
  • The board's 1.0 µF input capacitors block DC, so the source can sit at any DC level within the rails, such as a GPIO idling at 0 V or 3.3 V.
  • The 10 kOhm and 1 kOhm divider turns a 5 V square wave into about 0.45 Vpp, or a 3.3 V one into about 0.3 Vpp.
  • SD reads high above 1.2 V and low below 0.4 V (datasheet, p. 3), so a 3.3 V GPIO controls it directly; in shutdown the chip draws under 1 µA.
  • The trimmer only turns the gain down from the default; for more level, raise the input signal, not the supply.
  • Thermal shutdown and short-circuit protection are built in (datasheet, p. 1).

Specifications

Supply voltage
2.0 V to 5.5 VDiodes PAM8302A datasheet DS41333, p. 3
Absolute maximum supply
6.0 VDiodes PAM8302A datasheet DS41333, p. 2
Output power at 5 V
2.5 W into 4 ohm, 1.5 W into 8 ohm at 10 % THD+N (typical)Diodes PAM8302A datasheet DS41333, p. 3
Gain
23.5 dB typical (Adafruit board: 24 dB default, trimmer turns it down)Diodes PAM8302A datasheet DS41333, p. 3; Adafruit #2130 product page
Peak efficiency
85 % typical, 88 % maximumDiodes PAM8302A datasheet DS41333, p. 3
Quiescent current
4 mA typical, 8 mA maximum; shutdown under 1 µADiodes PAM8302A datasheet DS41333, p. 3
Shutdown input
High above 1.2 V, low below 0.4 VDiodes PAM8302A datasheet DS41333, p. 3
Breakout inputs
A+ and A- through 1.0 µF capacitors; tie A- to ground for single-ended audioAdafruit Mono 2.5W Class D Audio Amplifier (#2130) product page
Output
Bridge-tied, about 250 kHz PWM; any 4 ohm or higher speakerAdafruit Mono 2.5W Class D Audio Amplifier (#2130) product page

From the PAM8302A 2.5W Filterless Class-D Mono Audio Amplifier, DS41333 Rev. 6-2, published by Diodes Incorporated.

Common mistakes

  1. Speaker - wired to ground

    The output is bridge-tied (Adafruit #2130): both terminals switch. Grounding one shorts the output; connect the speaker only across + and -.

  2. Leaving A- floating

    With a single-ended source and A- unconnected, the differential input picks up noise and the volume drops. Tie A- to GND (Adafruit #2130).

  3. Square wave straight from a pin

    A full 5 V square wave at 24 dB gain clips and sounds harsh. Add the 10 kOhm and 1 kOhm divider, or turn the trimmer down.

  4. Expecting stereo

    The PAM8302 is mono. For two speakers use a PAM8403 or two PAM8302 boards.

PAM8302 questions

PAM8302 or PAM8403?

The PAM8302 is mono, 2.5 W into 4 ohm at 5 V (Diodes datasheet, p. 3), with differential inputs and a volume trimmer on Adafruit's board. The PAM8403 is stereo, 3.2 W per channel into 4 ohm. Choose by the number of speakers.

Can the PAM8302 run from 3.3 V?

Yes, it works down to 2.0 V (datasheet, p. 3), but the power falls: at 3.6 V it gives about 1.25 W into 4 ohm. For full volume use 5 V.

How do I connect a single-ended audio source?

Signal into A+, A- to ground (Adafruit #2130). The board's 1.0 µF capacitors remove any DC offset.

Is the PAM8302 better than an LM386?

For battery and USB projects, yes: Adafruit calls it an upgrade from the LM386, with 85 % to 88 % efficiency (datasheet, p. 3) and 2.5 W from 5 V, where an LM386 gives well under a watt and runs warmer.

Build something with the PAM8302

  • Talking clock

    Announce the hour through a speaker.

    Build this

  • Loud alarm siren

    A battery alarm that wails when a door opens.

    Build this

  • Game sound effects

    Add beeps and jingles to a handheld game.

    Build this
For AI assistants

This page as plain Markdown, for ChatGPT, Claude or your own agent. /components/pam8302.md

What will you build with it?