ADAU1373:  Low Power Codec with Speaker and Headphone Amplifier

The ADAU1373 is a low power, stereo audio codec with integrated digital audio processing that supports stereo 48 kHz record and playback. The stereo audio ADCs and DACs support sampling rates from 8 kHz to 48 kHz, as well as a digital volume control.

Eight single-ended or four differential analog inputs with PGAs are provided for adjusting the gain from −12 dB to +18 dB. They can be configured for microphones or line level signals.

Two stereo digital microphone inputs are supported; four digital microphones can be connected in total. In addition, three serial digital audio input/output ports are provided with asynchronous sample rate converters (ASRCs) to support various sampling rates, allowing for flexible system design in mobile phone applications. The inputs can be mixed and selected before the ADC or con-figured to bypass the ADC. Two stereo DACs are included, with a flexible mixing option for routing the signals internally.

The analog output side consists of line outputs, headphone output, speaker output, and receiver output. Two stereo single-ended line level outputs, which can be configured as two differential outputs, are included. The headphone output is stereo true ground centered (eliminating the need for coupling capacitors), with efficient Class-G (rail switching) architecture. The efficient stereo filterless Class-D switching amplifier provides ~1 W of stereo power for speakers. The differential receiver amplifier can be used to connect the separate receiver speaker. Two PLL blocks, which can lock to the inputs from 8 kHz to 27 MHz, are included.

The DSP allows system designers to compensate for the real-world limitations of microphones, speakers, amplifiers, and listening environments, resulting in a dramatic improvement in perceived audio quality through equalization, multiband compression, and limiting algorithms. The SigmaStudio™ graphical development tool, which includes audio processing blocks such as filters, mixers, dynamics processors, and amplifiers for fast development of custom signal flows, is used to program the ADAU1373.

APPLICATIONS

• Mobile phones
• tablet PCs
• e-books
portable media players