Adafruit STEMMA Piezo Driver Amp - PAM8904

Piezos generate sound when an AC voltage is applied, with volume increasing as voltage peaks higher. Using a standard 3V logic microcontroller, you can achieve 3V peak-to-peak with PWM out, or double that with differential outputs. For more intensity or distance-sensing applications using ultrasonic bounces, the PAM8904 amplifier is ideal.

This specialized piezo amplifier is designed for up to 300 KHz, unlike typical audio amplifiers. It features a switched-cap piezo driver with bridge-tied load (BTL) output and a built-in boosting circuit that multiplies voltage, producing up to 13V peak-to-peak. Our breakout board, based on the 2mm JST-PH STEMMA format, facilitates loud and powerful sound output.

Operating the device is straightforward: supply 3 to 5VDC to the Vin and GND pins and input a square wave from 20Hz to 300KHz on the signal pin. A dual DIP switch allows you to adjust gain settings: off, x1, x2, or x3. The differential output with 2x gain results in 4xVin peak-to-peak across piezo terminals. Connect the piezo to the terminal block to get started.

Be cautious when setting gain: with 5VDC power, avoid x3 gain to prevent exceeding the driver's specifications, while it's feasible at 3.3V power. Note that piezo elements and 3-pin JST PH cables, available separately, are required for operation.