Analog Devices ADAU1787 Low Power Codec Incorporating Digital Signal Processors

one month ago by Abdulwaliy Oyekunle

The ADAU1787 is one of the latest digital processing solutions from Analog Devices. The device is a low-power codec incorporating digital signal processors (DSPs) within a robust evaluation board for applications in multimedia speaker systems, smartphones, and more.

Key Features

ADAU1787 features a programmable FastDSP audio processing engine with a sampling rate of up to 768KHz. The product features 24-bit data converters. It has four analogue-to-digital converters (ADCs), two digital signal processors (DSPs) and two digital-to-analogue converters (DACs).

The DSPs process the inputs and the output coming from digital-to-analogue converters. The process of conversion of signals by the data converters is optimized for low latency. This makes the component ideal for use in noise-cancelling headsets.

 

Compatability with SigmaStudio 

Per the ADAU1787’s datasheet, the FastDSP audio processing engine can be programmed using SigmaStudio, an application software by Analog Devices. SigmaStudio features a library of audio processing blocks such as filters, mixers, and low-level digital signal processing functions. The software also supports a graphic user interface (GUI) that allows users to design DSP signal flows. The ADAU1787 also features eight digital microphone inputs and two analogue differential audio inputs that can be configured as either a line output or headphone driver.

 

Power Supply

The product has flexible routing power supplies. It can be operated from an analogue power supply ranging from -0.3V to +1.98V and a digital power supply ranging from -0.3V to +1.21V. It also has a supply for digital input and output pins ranging from -0.3V to +1.98V. The  ADAU1787 is a power-efficient product that consumes only about 11.027mW. It can function reliably in temperatures ranging from −40°C to +85°C.

Furthermore, the ADAU1787 has a clock speed of 24.576MHz with a bandwidth within the audio range of 20Hz to 20KHz. It also features biquad filters, limiters, and volume controls. 

 

The evaluation board for the ADAU1787.

The EVAL-ADAU1787Z evaluation board. Image Credit: Analog Devices.

 

 

Signal and Audio 

The signal-to-noise ratio of the ADAU1787 is 96dB when an audio signal is passed through the ADCs with A-weighted filters, and 105dB when the audio signal is passed through the DACs with A-weighted filters. It can generate its internal clocks using the on-board bypassable fractional PLL. The PLL accepts inputs from 30KHz to 27MHz. It supports interfaces with I2C and SPI with a self-boot function from electronically erasable programmable read-only memory (aka EEPROM). 

 

Comparison with Other Audio Codecs

ADAU1788 is a comparable product by Analog Devices that features two ADCs and one DACs. Like ADAU1787, the ADAU1788 incorporates two digital signal processors. It also has a programmable FastDSP audio processing engine.The ADAU1777 also has features seven multipurpose pins for digital controls and outputs. The signal-to-noise ratio when an audio signal is passed through its digital to analogue converter is 108dB. It can be operated from an analog power supply that ranges from -0.3V to +3.63V.

 

Applications

With its audio processing cores, the ADAU1787 is ideal for use in noise-cancelling applications. It is suitable for use in a host of electronic devices including digital still and video cameras, multimedia speaker systems, headphones and smartphones. The product is packaged in a 42-ball, 2.695 mm × 2.320 mm Wafer-level chip-scale packaging (WLCSP). 

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