The STA350Bx 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 STA350Bx 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 STA350Bx contains the ternary, binary and binary differential implementations, a subset of the full capability of the FFX processor.
The STA350Bx 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 STA350Bx 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 8 W speakers. Two channels can be provided by two full-bridges, providing up to 2 x 50 W of music power, by using standard 6 W speaker or 2 x 40 W by using 8 W 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 W load or 1 x 75 W by using a 4 W, setting the supply voltage at 25 V. Please refer to the package thermal characteristics and application suggestions for more details.
Also provided in the STA350Bx 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-to-market 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.
**Key Features**
Wide-range supply voltage
5 V to 26 V (operating range)
30 V (absolute maximum rating)
Four power output configurations
2 channels of ternary PWM (stereo mode) (2 x 50 W into 6 W at 25 V)
3 channels - left, right using binary and LFE using ternary PWM (2.1 mode) (2 x 18 W + 1 x 40 W into 2 x 4 W, 1 x 8 W at 25 V)
2 channels of ternary PWM (2 x 50 W) + stereo lineout ternary
1 channel of ternary PWM as mono-BTL (1 x 90 W into 3 W at 24.5 V)
FFX™ 100 dB SNR and dynamic range
Selectable 32 to 192 kHz input sample rates
I2 C control with selectable device address
Digital gain/attenuation +42 dB to -80 dB with 0.125 dB/step resolution
Soft-volume update with programmable ratio Individual channel and master gain/attenuation
Two independent DRCs configurable as a dual-band anti-clipper (B2DRC) or independent limiters/compressors
EQ-DRC for DRC based on filtered signals
Dedicated LFE processing for bass boosting with 0.125 dB/step resolution
Audio presets:
15 preset crossover filters
5 preset anti-clipping modes
Preset nighttime listening mode Individual channel and master soft/hard mute
Independent channel volume and DSP bypass
Automatic zero-detect mute
Automatic invalid input-detect mute
I2 S input data interface
Input and output channel mapping
Up to 8 user-programmable biquads per channel 3 coefficient banks for EQ presets storing with fast recall via I2 C interface
Extended coefficient dynamic up to -4..4 for easy implementation of high shelf filters
Bass/treble tones and de-emphasis control
Selectable high-pass filter for DC blocking
Advanced AM interference frequency switching and noise suppression modes
Selectable high or low bandwidth noise-shaping topologies
Selectable clock input ratio
96 kHz internal processing sample rate with quantization error noise shaping for very low cutoff frequency filters
Thermal overload and short-circuit protection embedded
