Stereo Audio Digital-to-Analog Converter IC with High-power Audio Power Amplifier from Atmel

The AT73C240 integrates a complete high-performance stereo audio digital-to-analog converter delivering a 90 dB dynamic range, followed by a 32-Ohm stereo headset driver with programmable volume control and mute function. The stereo DAC comprises a multi-bit sigma-delta modulator with dither, continuous time analog filters and analog output drive circuitry. The master clock is 256 or 384 times the sampling frequency, allowing the choice of input data rate up to 50 kHz, including standard audio rates of 48, 44.1, 32, 16 and 8 kHz. The stereo 32-Ohm headset drivers also include a mixer for a pair of stereo inputs.

The DAC outputs can also be played back through a mixer buffer stage to the integrated audio power amplifier. The mono buffer stage can also receive the mixing of the stereo inputs as well as the differential monaural auxiliary input (which can be, for example, from a voice CODEC output driver in a mobile phone). The audio power amplifier is a dual-mode AB class amplifier with differential output and programmable volume control. In full power mode, it is capable of driving an 8-Ohm loudspeaker at maximum power of 1W at 5.5V supply and 440mW at 3.6V supply. The volume, mute, power down, de-emphasis controls and 16-, 18-, 20-bit audio formats are digitally programmable via a 4-wire SPI bus and the digital audio data is provided through a multi-format I2S interface.

“We are very excited with the introduction of the AT73C240,” commented Michele Casetta, Marketing Manager for Atmel’s Power Management and Analog Audio Companion (PMAAC) Product Line. “After the great success of the AT73C213 audio DAC that was launched 4 years ago, the AT73C240 answers customers’ requests for a smaller package and lower price, while keeping the high quality and the powerful audio amplifier.”

“Atmel’s strategy to offer high quality analog features external to microcontroller ICs, in order to have highest quality performance using a lower-cost analog-optimized process, is getting increasing success in the market. The AT73C240 can be used with Atmel’s proprietary AVR® microcontroller family or with its SAM and CAP™ ARM®-based MCUs , allowing customers to get the highest audio quality at the lowest system cost. Also, the AT73C240 is a breakthrough solution for current and future consumer product generations where the generic digital processing integrated circuits are migrating below 90 nm technologies, while putting the analog section outside to decrease system cost,” concluded Michele Casetta.