Diodes Inc. : PAM8905 – 1.9W Class-D audio amplifier produces high SPL and helps extend battery life

The PAM8905 from Diodes Inc., is a 1.9W Class-D audio amplifier designed for audio systems which need to deliver a high Sound Pressure Level (SPL) output from a low supply voltage, such as that provided by a single-cell lithium-ion battery.

It achieves this with a built-in boost converter which generates the voltage rail for the output stage, while using a battery-tracking automatic gain control to adjust the gain and to limit battery current when the battery voltage is low, thus prolonging battery life.

Offering typical efficiency of 85%, the PAM8905 can drive up to 1.9W into an 8Ω speaker with a total harmonic distortion plus noise figure of just 1%. The fully synchronous topology of the boost circuit minimises the need for external components, while improving the efficiency and increasing the output power of the amplifier compared to a standard amplifier connected directly to the battery.

The PAM8905 features DC input-voltage protection to prevent damage to the speaker should the input voltage reach a high DC bias level. The device is also protected against output short-circuits with full auto-recovery, and has under-voltage lockout and over-temperature protection. It is supplied in a 12-pin CSP package measuring just 15mm x 20mm x 0.6mm.


  • Operating voltage range: 2.8V to 5.2V
  • Minimised On/Off pop noise
  • 20dB maximum gain
  • 95dB signal-to-noise ratio
  • -70dB PSRR
  • Thermal shut-down


  • Satellite navigation equipment
  • Portable electronics devices
  • Speakers


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