Analog Devices’ ADAU1373 is a low-Power stereo CODEC with integrated digital audio processing, supports stereo 48kHz recording and playback, stereo ADC and DAC support sampling rates from 8kHz to 48kHz and digital volume control, eight single-ended or four with PGA The differential input provides gain from -12dB to +18dB. The power consumption of 48kHz and 1.8V is 7mW for recording and 6mW for playback. It is mainly used in mobile phones, tablet computers, e-books, and handheld media players. This article introduces the main features of ADAU1373, block diagram, Stereo Class D application circuit diagram and ADAU1373 evaluation board circuit diagram, bill of materials, and PCB component layout.
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.
ADAU1373 main features:
1 stereo ADC and 2 stereo DACs with sampling rates from 8 kHz to 48 kHz
Low power: 7 mW record, 6 mW playback, 48 kHz at 1.8 V
8 single-ended or 4 differential inputs with PGA
2 microphone bias reference voltages with current sense
2 stereo digital microphone inputs
Flexible analog input/output mixers
1 stereo differential or 2 stereo single-ended line outputs
True ground-centered stereo Class-G headphone amplifier, capable of 2 × 50 mW into 16 Ω at 1.8 V, 10% THD
Filterless stereo Class-D speaker amplifier, capable of 2 × 880 mW into 8 Ω at 3.6 V, 10% THD
Differential earpiece amplifier capable of driving 32 Ω
2 PLLs, supporting input clocks from 8 kHz to 27 MHz
I2C control interface
Digital audio processing
3 digital audio input and output ports with ASRC
I2S, PCM, right-justified, left-justified modes
4.05 mm × 3.82 mm, 81-ball, 0.4 mm pitch WLCSP package
−40℃ to +85℃ operating temperature range
Mobile phones, tablet PCs, e-books, portable media players
Figure 1. ADAU1373 Functional Block Diagram
Figure 2. ADAU1373 Typical Stereo Class D Application Circuit Diagram
ADAU1373 Evaluation Board
The ADAU1373 is a low power audio codec that supports stereo record and playback. It provides eight single-ended or four differential analog inputs with PGA for adjusting the gain. The support for two stereo digital microphone inputs is provided so that, in total, four digital microphones can be connected. In addition, three serial digital audio in/out ports are provided with ASRCs to support various sampling rates at the input/output ports, allowing flexible system design.
The analog output side consists of line outputs, a headphone output, a speaker output, and a receiver output. The two stereo single-ended line level outputs are included, which can be configured as two differential outputs. The headphone output is stereo true- ground-centered with efficient Class-G architecture. The efficient stereo filterless Class-D switching amplifier pro-vides around 1 W stereo power for speakers. The differential receiver amplifier can be used to connect the separate receiver speaker.
The ADAU1373 evaluation board includes the complete application circuit for the ADAU1373. The board is featured with USBi connection to the SigmaStudio™ graphical develop-ment tool running on a host PC, which is used to program the ADAU1373.
Included in this user guide is a detailed description for the ADAU1373 evaluation board. It is recommended that the ADAU1373 data sheet be read along with this user guide. Full details about the part are available in the ADAU1373 data sheet, which provides more detailed information about the specifica-tions, internal block diagrams, and application guidance for the codec IC.
Figure 3. ADAU1373 Evaluation Board Circuit Diagram (1)
Figure 4. ADAU1373 Evaluation Board Circuit Diagram (2)
Figure 5. ADAU1373 Evaluation Board Circuit Diagram (3)
Figure 6. ADAU1373 Evaluation Board Circuit Diagram (4)
Figure 7. ADAU1373 Evaluation Board Circuit Diagram (5)
Figure 8. ADAU1373 Evaluation Board Circuit Diagram (6)
Figure 9. ADAU1373 Evaluation Board Circuit Diagram(7)
Figure 10. ADAU1373 Evaluation Board Circuit Diagram(8)
Figure 11. ADAU1373 Evaluation Board Circuit Diagram(9)
ADAU1373 Evaluation Board Bill of Materials:
Figure 12. ADAU1373 Evaluation Board Power Section
Figure 13. ADAU1373 Evaluation Board Digital Audio Interface and Drizzle Digital Microphone Interface Section
For details, see: