Diodes Incorporated's PAM8905 is a smartphone designed to operate from a single-cell lithium-ion battery. It is a new 1.9WD class audio amplifier designed for audio systems that require high sound pressure level (SPL) output from high-power speakers. The power supply voltage is low.
The device achieves this by using a built-in boost converter that generates a voltage rail for the output stage, while using battery tracking automatic gain control (AGC) to regulate gain and limit battery current when battery voltage is low, thereby extending Up battery life.
With its highly efficient Class D audio power amplifier and integrated boost converter, the PAM8905 can drive up to 1.9W 8ohm speakers with only 1% total harmonic distortion and noise (THD + N). Compared to a standard amplifier connected directly to the battery, the fully synchronous topology of the boost circuit minimizes external components, improves efficiency, and maximizes the amplifier's output power. The built-in AGC function ensures excellent sound reproduction and further helps extend battery life.
The PAM8905 has a DC input voltage protection function to prevent damage to the speaker if the input voltage has a high DC bias level. The device also features full auto-recovery to prevent output short circuits, and features under-voltage lockout (UVLO) and over-temperature protection. PAM8905 is available in a 12-pin U-WLB1520-12 CSP package measuring only 15mm x 20mm x 0.6mm, providing a low pin count and small size solution to save board space.
