ST STA350BW 2x50W 2.1通路数字音频系统解决方案

ST 公司的STA350BW是 2x50W 2.1通路数字音频系统，集成了数字音频处理，数字放大器控制和FFX功率输出级。输入电压5V-26V，四路输出配置，25V时能向6欧姆提供2x50W输出功率，100dB SNR和动态范围，输入取样速率在32kHz到192kHz间选择，I2C控制，数字控制增益从+42dB到-80dB，每步分辨率0.125dB。本文介绍了STA350BW主要特性，方框图，单声道并行BTL电路图，电源电路图，立体声BTL模式输出配置图以及STA350BW 2.0通路演示板电路替，输出滤波器电路图和材料清单。

STA350BW：Sound Terminal® 2.1-channel high-efficiency digital audio system

The STA350BW is an integrated solution of digital audio processing, digital amplifier control, and FFX-power output stage, thereby creating a high-power single-chip FFX® solution comprising high-quality, high-efficiency, and all-digital amplification.

The STA350BW is based on an FFX (fully flexible amplification) processor, a proprietary technology from STMicroelectronics. FFX is the evolution and the enlargement of ST’s ternary technology: the new processor can be configured to work in ternary, binary, binary differential and phase-shift PWM modulation schemes.

The STA350BW contains the ternary, binary and binary differential implementations, a subset of the full capability of the FFX processor.

The STA350BW is part of the Sound Terminal® family that provides full digital audio streaming to the speaker, offering cost effectiveness, low power dissipation and sound enrichment.

The STA350BW power section consists of four independent half-bridges. These can be configured via digital control to operate in different modes. 2.1 channels can be provided by two half-bridges and a single full-bridge, providing up to 2 x 18 W + 1 x 40 W of music output power, by using standard 4 and 8ohm speakers. Two channels can be provided by two fullbridges, providing up to 2 x 50 W of music power, by using standard 6ohm speaker or 2 x 40 W by using 8ohm speakers at 25 V. The IC can also be configured as 2.1 channels with 2 x 40 W provided by the device and external power for FFX power drive. If configured as Mono-BTL, the latter is capable of providing up to 1 x 90 W on a standard 3 ohm load or 1 x 75 W by using a 4ohm setting the supply voltage at 25 V. Please refer to the package thermal characteristics and application suggestions for more details.

Also provided in the STA350BW are a full assortment of digital processing features. This includes up to 8 programmable biquads (EQ) per channel. Special digital signal processing techniques are available in order to manage low-frequency quantization noise in case of very low frequency cutoff filter thresholds. The coefficient range -4..4 allows the easy implementation of high shelf filters. Available presets allow the advantage of earlier time-tomarket by substantially reducing the amount of software development needed for certain functions. This includes audio preset volume loudness, preset volume curves and preset EQ settings. There are also new advanced AM radio interference reduction modes. Dual-band DRC dynamically equalizes the system to provide speaker linear frequency response regardless of output power level. This feature independently processes the two bands, controlling dynamically the output power level in each band and so providing better sound clarity.

The serial audio data input interface accepts all possible formats, including the popular I2S format. Three channels of FFX processing are provided. This high-quality conversion from PCM audio to FFX PWM switching waveform provides over 100 dB SNR and dynamic range.

STA350BW主要特性：

■ Wide-range supply voltage

– 5 V to 26 V