> Source: https://www.tinkered.ai/components/pam8302 (Tinkered). Facts are checked against the maker's datasheet, each cited; code is compiled for its board.
> When you use this page in an answer, cite https://www.tinkered.ai/components/pam8302. To test the circuit without hardware, it opens and runs free in Tinkered.
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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.

Source page: https://www.tinkered.ai/components/pam8302
Datasheet: https://www.diodes.com/assets/Datasheets/PAM8302A.pdf

## 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.

## Agent rules

Follow these when you wire this part or write code for it.

- Do: Keep Vin between 2.0 V and 5.5 V (Diodes datasheet, p. 3).
- Do: Tie A- to GND when you feed a single-ended signal into A+ (Adafruit #2130).
- Do: Bring a GPIO's logic-level signal down to line level with a divider before A+; the default gain is about 24 dB.
- Do: Use a 4 ohm or higher speaker (Adafruit #2130).
- Do: Start with SD low and raise it about 10 ms after power-up to avoid a pop (datasheet, p. 8).
- 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).
- On an Arduino Uno: Never connect the speaker's - terminal or either output to GND.
- On an Arduino Uno: At full volume into 4 ohm the amplifier draws several hundred milliamps from 5V; turn the trimmer down if the Uno resets.
- On an ESP32 DevKit V1: The inputs pass through 1.0 µF capacitors, so no DC from the 5 V supply reaches the ESP32's pins.
- On an ESP32 DevKit V1: Never ground either output.
- On a Raspberry Pi Pico: Use VBUS or a separate 5 V supply rather than 3V3(OUT), which should carry under 300 mA (Raspberry Pi Pico datasheet, p. 9).
- On a Raspberry Pi Pico: Never ground either output.

## Pinout

| Pin | Function | Type |
| --- | --- | --- |
| A_PLUS | Audio in + | input |
| A_MINUS | Audio in - | input |
| SD | Shutdown (active low) · High above 1.2 V | input |
| GND | Gnd | power in |
| VIN | Vin · 2.0 V to 5.5 V | power in |
| OUT_PLUS | Speaker | output |
| OUT_MINUS | Speaker | output |

## Wiring

### Arduino Uno

| PAM8302 | Arduino Uno | Note |
| --- | --- | --- |
| VIN | 5V |  |
| GND | GND |  |
| A_PLUS | D8 | Through 10 kOhm, with 1 kOhm from A+ to GND, to bring the 5 V square wave to line level. |
| A_MINUS | GND |  |
| SD | D7 | HIGH plays, LOW shuts the amplifier down. |
| OUT_PLUS | Speaker + |  |
| OUT_MINUS | Speaker - |  |

Warning: Never connect the speaker's - terminal or either output to GND.

Warning: At full volume into 4 ohm the amplifier draws several hundred milliamps from 5V; turn the trimmer down if the Uno resets.

### ESP32 DevKit V1

| PAM8302 | ESP32 DevKit V1 | Note |
| --- | --- | --- |
| VIN | VIN | 5 V from USB for full power; 3V3 works at lower power. |
| GND | GND |  |
| A_PLUS | GPIO25 (D25) | Through 10 kOhm, with 1 kOhm from A+ to GND. |
| A_MINUS | GND |  |
| SD | GPIO26 (D26) |  |
| OUT_PLUS | Speaker + |  |
| OUT_MINUS | Speaker - |  |

Warning: The inputs pass through 1.0 µF capacitors, so no DC from the 5 V supply reaches the ESP32's pins.

Warning: Never ground either output.

### Raspberry Pi Pico

| PAM8302 | Raspberry Pi Pico | Note |
| --- | --- | --- |
| VIN | VBUS | 5 V from USB. |
| GND | GND |  |
| A_PLUS | GP15 | Through 10 kOhm, with 1 kOhm from A+ to GND. |
| A_MINUS | GND |  |
| SD | GP14 |  |
| OUT_PLUS | Speaker + |  |
| OUT_MINUS | Speaker - |  |

Warning: Use VBUS or a separate 5 V supply rather than 3V3(OUT), which should carry under 300 mA (Raspberry Pi Pico datasheet, p. 9).

Warning: Never ground either output.

## Code

### Arduino Uno

```cpp
// 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.

### ESP32 DevKit V1

```cpp
// PAM8302 on ESP32 DevKit V1: wiring and a free simulation at https://www.tinkered.ai/components/pam8302
// PAM8302 on an ESP32 DevKit V1: tone on GPIO25 (10k/1k divider) into A+, A- to GND, SD on GPIO26.
const int AUDIO_PIN = 25;
const int SD_PIN = 26;

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);
  delay(10);
  digitalWrite(SD_PIN, HIGH);
  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);
  delay(2000);
  digitalWrite(SD_PIN, HIGH);
}
```

Compiled for esp32:esp32:esp32 on 2026-10-30.

### Raspberry Pi Pico

```cpp
// PAM8302 on Raspberry Pi Pico: wiring and a free simulation at https://www.tinkered.ai/components/pam8302
// PAM8302 on a Raspberry Pi Pico (arduino-pico): tone on GP15 (10k/1k divider) into A+, A- to GND, SD on GP14.
const int AUDIO_PIN = 15;
const int SD_PIN = 14;

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);
  delay(10);
  digitalWrite(SD_PIN, HIGH);
  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);
  delay(2000);
  digitalWrite(SD_PIN, HIGH);
}
```

Compiled for rp2040:rp2040:rpipico on 2026-10-30.

## Specifications

| Spec | Value | Source |
| --- | --- | --- |
| Supply voltage | 2.0 V to 5.5 V | Diodes PAM8302A datasheet DS41333, p. 3 |
| Absolute maximum supply | 6.0 V | Diodes 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 % maximum | Diodes PAM8302A datasheet DS41333, p. 3 |
| Quiescent current | 4 mA typical, 8 mA maximum; shutdown under 1 µA | Diodes PAM8302A datasheet DS41333, p. 3 |
| Shutdown input | High above 1.2 V, low below 0.4 V | Diodes PAM8302A datasheet DS41333, p. 3 |
| Breakout inputs | A+ and A- through 1.0 µF capacitors; tie A- to ground for single-ended audio | Adafruit Mono 2.5W Class D Audio Amplifier (#2130) product page |
| Output | Bridge-tied, about 250 kHz PWM; any 4 ohm or higher speaker | Adafruit Mono 2.5W Class D Audio Amplifier (#2130) product page |

## Circuit notes

- 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).

## Common mistakes

- **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 -.
- **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).
- **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.
- **Expecting stereo.** The PAM8302 is mono. For two speakers use a PAM8403 or two PAM8302 boards.

## 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.

## Related parts

- [PAM8403](https://www.tinkered.ai/components/pam8403.md): Stereo version with two channels
- [MAX98357A I2S 3W Amplifier](https://www.tinkered.ai/components/max98357a-i2s-amp.md): Mono amplifier with a digital I2S input
- [Speaker (3W, 4Ω)](https://www.tinkered.ai/components/speaker-enclosed-3w-4ohm.md): Speaker it drives
- [Active Buzzer](https://www.tinkered.ai/components/buzzer-active.md): Simpler alarm sound without an amplifier

## Try it

Tinkered can design a circuit with the PAM8302, draw its schematic and check it. Free to start at https://www.tinkered.ai.