Power amplifier suits portable applications

The TPA2013D1 generates high output power from a low supply voltage without distorting the audio.

Texas Instruments has released a monolithic, filter-free, Class-D audio power amplifier with an integrated boost convertor, which provides constant output power for portable applications such as personal navigation devices, PDAs, mobile phones, portable media players and handheld gaming devices.

The combination of the 2.7W Class-D amplifier and integrated boost convertor provides 85% overall efficiency, with little heat dissipation, to prolong battery life when the user is playing music or in a telephone conversation.

The TPA2013D1 generates high output power from a low supply voltage without distorting the audio, and can also supply the power of external devices such as TI's TPA2010D1, and other similar Class-D amplifiers.

The device has a supply voltage operation of 1.8 to 5.5V to simplify power supply design and allow for direct connection to the battery.

The new device provides a maximum output power of 2.7W across a 4ohm load or 2.2W across an 8ohm load in addition to providing an adjustable constant output power of up to 1.5W in the entire Lithium-Ion battery range of 2.3 to 4.8V.

This capability makes the audio output power insensitive to battery voltage fluctuations, thereby maintaining audio quality and volume as the battery discharges.

The design of the TPA2013D1 eliminates the requirement for some external components enabling a total solution size of 6.5 x 6.5mm, which includes the amplifier, boost convertor and external components.

This represents a board area reduction of more than 50% compared to typical solutions.

The combination of size, features and performance reduces overall system cost and allows for a sleeker end product.

"Consumers expect smaller, more power-efficient portable devices, including mobile phones, where future battery voltages may go as low as 2.3V next year and even lower in 2009 and 2010", said Gary Reichmuth, TI's Manager Of Audio and Imaging Products.

"Benefiting from TI's in-depth systems expertise, products like the TPA2013D1 allow end equipment manufacturers to meet these consumer demands while increasing performance and functionality".

All internal modules run off the same reference clock, silencing potential audible beat frequencies that could occur when using a separate discrete amplifier and boost convertor.

The synchronised clock and power supply rejection ratio (PSRR) of 95dB at 217Hz, serve to further reduce noise in the system, avoiding "buzzing" on amplifier outputs that can often be generated from RF power amplifiers in GSM phones, for instance.

The TPA2013D1 provides thermal and short circuit protection with an auto recovery option to ensure excellent reliability and robust operation.

The device's pinout has been optimised to reduce EMI, providing easy layout and meeting EMI requirements of the Federal Communications Commission (FCC).

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