Stereo headphone amplifier boosts battery life for consumer handhelds

Toshiba’s new amplifier, the TC94B06, is a class-G amplifier that achieves significantly higher efficiency than conventional class-A/B operation while retaining inherently low audio distortion. It will allow customers to build ultra low-power headphone amplifiers while avoiding the high costs and complex filtering associated with a class-D amplifier. A class-G amplifier operates at low supply voltages for the majority of audio-signal levels, but is able to increase its dynamic range temporarily when high signal levels are received. This enhances energy efficiency and reduces overall power consumption.

The TC94B06 delivers high audio performance, with less than 0.02% distortion (THD+N), at low active current of less than 1.5mA. In addition, its 1µA standby mode, allowing designers to use power management to further increase system energy efficiency for maximum battery lifetime. The versatile device is able to drive loads from 16Ω to 600Ω, allowing use in a variety of equipment types.

In addition, the TC94B06 saves component count and board space compared to alternative linear or digital devices. Its built-in DC/DC converter circuitry allows direct connection to the battery. Internal volume control enhances the system dynamic range, allowing adjustment from -60db to +4dB, and saves external components. Also there is no requirement for output coupling capacitors. The integrated I2C port provides a convenient, industry-standard interface for volume control and diagnostic monitoring. The device is delivered in a miniature 16-pin 0.4mm-pitch wafer-level chip-scale package (WCSP) measuring just 1.65mm x 1.65mm.