Class-D amp offers cost-efficient, smartphone friendly solution

Silicon Laboratories Inc. has introduced a 5-W stereo digital Class-D audio amplifier designed to address EMI issues in price- and noise sensitive consumer electronics applications like smartphone docks, TV sound bars/monitors, boom boxes and radios. According to the company, the Si270x amplifier reduces radiated interference by 10X in the EMI compliance band, by 100X in the FM radio band and by 1000X across the AM band compared to existing Class-D solutions.

The Si270x integrates a power stage, PWM DAC, and an internal audio DSP that includes a seven-band equalizer, dynamic range compressor, tone control, volume control, tone generation and 3D sound support. The Si270x is also designed to be combined seamlessly with the company's Si473x AM/FM radio tuner products to enable complete consumer audio platform solutions.

Other key features include:

  • Digital input Delta-Sigma PWM
  • AM radio band noise-free notch
  • GSM/iPhone friendly
  • Wideband PWM carrier switching
  • Power stage slew rate control
  • Power stage feedback for PSR/THD
  • 88% efficiency with >50 dB PSRR
  • 95 dB dynamic range and <0.1% THD
  • Stereo PWM DAC line analog outputs
  • Master/slave I2S with 3 inputs
  • Dual supply voltage: 2.7–3.6 V main and 4.0–6.6 V power stage

 The Si270x is available in 4×4 24-pin Power QFN and 7×7 48-pin Power TQFP packages. Samples and pre-production quantities are available today in a 24-pin QFN package.

Pricing in 10,000-unit quantities begins at $1.17 (USD). A full-featured evaluation board (Si270x-A-EVB) is available priced at $325 (USD).

Silicon Laboratories Inc. , 877-444-3032,

Related links:
Si270x information page
Si270x datasheet
Video overview of the Si270x Class-D amplifier

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