Two new 25-mW Class-G stereo headphone amplifiers from Texas Instruments were released using DirectPath technology. These devices minimize power dissipation by adjusting the voltage supply to the audio signal. In tests performed by TI, the TPA6140A2 and TPA6141A2 reduced power consumption by 30 percent over a competing ground-reference Class-AB device, allowing for the length of music playback to be increased by 20 percent.
Included in the devices is TI's DirectPath technology which removes the need for large DC-blocking capacitors to improve low-frequency audio fidelity. As well, the devices include built-in pop suppression circuitry to remove pop noises when the amplifier power on.
Additional features and benefits of the TPA6140A2 and TPA6141A2:
– These amplifiers consume only 0.6 mA/channel quiescent current and deliver 5 mW/channel into a 32-ohm load, while keeping the total supply current below 5 mA, to extend battery life
– The TPA6140A2 and TPA6141A2 enable an energy-efficient system when coupled with TI's low-power audio converters, speaker amplifiers, OMAP 3 processors and TMS320C550x and TMS320C540x devices
– The TPA6140A2 provides a variable gain range of -59 dB to +4 dB programmable via a 32-step I2C volume control to maximize design flexibility. The TPA6141A2 offers two fixed gain settings of 0 dB and +6 dB for customers who require less flexibility
– Separate SGND pin reduces ground loop noise when interfacing with a non-headphone accessory
The TPA6140A2 is available in volume now at a suggested resale pricing is $0.95 in 1,000-unit quantities. The TPA6141A2 will be available in 2009.