Class-G amplifier delivers analog audio performance, extends battery life

STMicroelectronics has introduced a stereo headphone amplifier IC that achieves higher efficiency than previous-generation devices, enabling listeners to enjoy high-quality sound for longer between battery charges.

The TS4621 delivers the high audio performance of a traditional analog amplifier, and saves power by operating from a lower supply voltage for the majority of audio-signal levels. While connected to two supplies, power is drawn from the higher-voltage rail for only those brief periods when peak audio power levels are required. By using this principle, known as class G, the TS4621 is among the first such headphone amplifiers targeting portable applications.

The TS4621 simplifies system design with features including an industry-standard I2C interface enabling digital volume control from -60 dB to +4 dB, and integrated switch-on/switch-off circuitry that eliminates pop and click noise. Its ultra-small 1.65 mm x 1.65 mm chip-scale package allows the amplifier to be positioned very close to the headphone connector for optimum audio performance.

Joining ST's portfolio of audio ICs targeting products such as cellphones, multimedia and MP3 players, game terminals and GPS devices, the TS4621 has four-times lower quiescent current consumption than the existing TS4601; a class AB amplifier. The saving is valuable in energy-sensitive applications such as battery-powered devices. At the same time, the TS4621 excels in key audio performance parameters to deliver an outstanding listening experience for end users.

Major features of the TS4621:

  • 0.006 percent THD+N at 1 kHz
  • 100 dB PSRR at 217 Hz (high immunity to GSM signaling noise)
  • 100 dB SNR at 0 dB gain
  • 0.6 mA/channel quiescent current
  • 2.1 mA/channel active current at 100 µW audio output

Availability and Pricing
The TS4621 is sampling to lead customers now and will be available for production orders from April 2010, priced from 0.95 US Dollars for orders over 1000 units.

Datasheet: TS4621

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