Eight-channel High Dynamic-Range Audio Processor from STMicroelectronics

July 3 2014, 10:00
STMicroelectronics’ STA311B is a single-chip solution for digital audio processing and control in multichannel applications and provides output capabilities for FFX (full flexible amplification). In conjunction with an FFX power device, it provides high-quality, high-efficiency, all digital amplification. The device is extremely versatile, allowing for input of most digital formats including 6.1/7.1-channel and 192 kHz, 24-bit DVD-audio, DSD/SACD. In a 5.1 application the additional 2 channels can be used for audio line-out or headphone drive.
The STA311B is a single chip solution for digital audio processing and control in multichannel applications, providing FFX (Full Flexible Amplification) compatible outputs. Together with a FFX power amplifier the STA311B can provide high-quality, high-efficiency, all-digital amplification, ideal for active speakers, docking stations, and digital media players, from entry-level to high-end equipment.

The chip accepts digitized audio input information in either I2S (left or right justified), LSB or MSB first, with word lengths of 16, 18, 20 and 24 bits. Its pop-noise removal feature does not discriminate against the music genre but instead prevents any audible transients or pops finding their way through to the power amp where they may damage the speakers. Device control is via an I2C interface.
HDR signal acquisition allows digital signals with a dynamic range exceeding 130dB to be generated without the need for expensive, high-performance ADCs (Analog-to-Digital Converters).  This technique, for which ST has a patent application pending, allows the STA311B to process sounds as low as a whisper or as high as jet engine noise with the same degree of clarity, delivering an unprecedented audio quality. 
Housed in a compact 8.0x8.0x0.9mm VFQFPN package, the STA311B embeds eight audio-processing channels with up to 10 independent user-selectable biquadratic filters per channel, input and output mixing capabilities, multi-band dynamic range compression, advanced pop-free operation, auto-detection of input sampling frequency, input and output (pre- and post-processing) RMS (Root Mean Square)  metering, ST’s proprietary FFX Pulse Width Modulation technology, and HDR acquisition inputs in a single device. This allows audio equipment and subsystem manufactures to reduce costs by developing multiple products based on the same design still tailored for a variety of price/performance scenarios.
The STA311B’s input/output RMS metering function delivers an increased level of safety to the final product without any additional hardware cost. Whereas previous solutions relied on using over-specified and more expensive speakers capable of sustaining high power peaks, the STA311B allows the application to suppress unwanted energy surges that could potentially damage the speakers. The STA311B’s pop-free circuitry also enables a seamless start-up, eliminating unwanted noise due to the bridge charge sequence in both Single-End and Bridge-Tied Load configurations.
“Ever since SGS Microelettronica, one of our parent companies, developed the first single-chip audio power amplifiers in 1968, we have set new standards year after year, and with the STA311B we have raised the bar again. The unprecedented combination of performance and flexibility built into the STA311B allows our customers to simultaneously reduce their costs and improve their customers’ listening experience,” explains Andrea Onetti, General Manager Analog and Audio Systems Division, STMicroelectronics.
The latest member of the well-established Sound Terminal product family, the STA311B is fully supported by ST’s free APWorkbench software development tool that allows all ST audio products to be configured via an intuitive, user-friendly graphical interface.
More information about the STA311B here
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