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TI intros charge pump-based headphone amp

Posted: 10 Jan 2007 ?? ?Print Version ?Bookmark and Share

Keywords:amplifiers? headphone amplifiers? headphone? Texas Instruments? DirectPath?

Texas Instruments Inc. (TI) has introduced a new headphone amplifier optimized for cellular handsets and other portable audio applications.

The TPA6130A2, the first product in the company's DirectPath line of charge pump-based headphone amplifiers, is said to outperform other charge pump-based headphone drivers on the market today, offering a PSRR of 109dB, the lowest quiescent current at 4mA, the first differential stereo inputs and 64-step software-based volume control. These features make it possible for manufacturers to minimize noise disturbances, extend battery life and maximize audio quality in cellphones, PDAs, portable media players and portable audio players.

Traditional headphone amplifiers require large-output DC blocking capacitors that typically require significant board space and have a high profile. To reduce this solution size, manufacturers might use smaller, lower quality capacitors, which impact the low frequency response of headphones and limit the overall base content.

Charge-pump architecture
TI's DirectPath charge-pump architecture generates a negative supply rail, so that the amplifier can reference true ground. This provides a direct path from the amplifier outputs to the headphone speakers and eliminates the need for any DC blocking capacitors. This enables developers to create a more elegant and compact headphone driver solution that improves low frequency response, while lowering system cost and PCB space requirements.

The TPA6130A2 offers a quiescent current of 4mA, said to be the lowest in the industry, and shutdown current of less than 1?A. This efficiency enables developers to create headphones that maximize battery life and extend listening time.

Cost is a major consideration in headphone design, and TI has integrated volume control into the TPA6130A2, eliminating the need for an additional potentiometer to control volume. Because the 64-step volume control is managed via software over an I?C control bus, it also has the added benefit of maximizing the headphone SNR. Since volume is controlled via software, developers can drive the audio source at its maximum output and reduce or increase volume within the amplifier, enabling the highest possible SNR and the highest audio quality.

Maximum user experience
TI is focused on maximizing the user experience at all levels and has implemented its high-performance circuitry in the TPA6130A2, which suppresses pop noise to an inaudible level. Other features of this device include 138mW of output power per channel into standard 16-ohm headphone speakers at 5V, 0.0055 percent THD+N (35mW at 1kHz) and 8kV ESD protection. Its wide voltage rail of 2.5-5.5V enables developers to connect the headphone amplifier directly to the power supply, simplifying overall design by eliminating the need for a dedicated power management device, such as an LDO regulator.

The TPA6130A2 is available now in production volumes in a Pb-free 2-by-2mm WCSP package and costs $1.55 each in 1,000-unit quantities. QFN 4-by-4mm packaging an evaluation module and software are planned for release in early 2007.

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Related Datasheets
Part Number Description Category
? TPA6130A2 138-mW DirectPath Stereo Headphone Amplifier With I2C Volume Control (Rev. B) Actives - Sensors and Transducers



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