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2.1-channel high-efficiency digital audio system

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Product overview


The STA333BW is an integrated solution of digital audio processing, digital amplifier controls and power output stages to create a high-power single-chip FFX digital amplifier with high-quality and high-efficiency. Three channels of FFX processing are provided. The FFX processor implements the ternary, binary and binary differential processing capabilities of the full FFX processor.

The STA333BW is part of the Sound Terminal®family that provides full digital audio streaming to the speakers and offers cost effectiveness, low power dissipation and sound enrichment.

The power section consists of four independent half-bridges. These can be configured via digital control to operate in different modes.

For example, 2.1 channels can be provided by two half-bridges and a single full-bridge, supplying up to 2 x 9 W + 1 x 20 W of output power or two channels can be provided by two full-bridges, supplying up to 2 x 20 W of output power.

The IC can also be configured as 2.1 channels with 2 x 20 W supplied by the device plus a drive for an external FFX power amplifier, such as STA533WF or STA515W.

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

Also provided in the STA333BW are a full assortment of digital processing features. This includes up to 5 programmable biquads (EQ) per channel. Available presets enable a time-to-market advantage by substantially reducing the amount of software development needed for functions such as audio preset volume loudness, preset volume curves and preset EQ settings. There are also new advanced AM radio interference reduction modes. The DRC dynamically equalizes the system to provide a linear frequency speaker response regardless of output power level.

  • All features

    • Wide-range supply voltage, 4.5 V to 21.5 V
    • Three power output configurations:
      • 2 channels of ternary PWM (2 x 20 W into 8 Ω at 18 V) + PWM output
      • 2 channels of ternary PWM (2 x 20 W into 8 Ω at 18 V) + ternary stereo line-out
      • 2.1 channels of binary PWM (left, right, LFE) (2 x 9 W into 4 Ω +1 x 20 W into 8 Ω at 18 V)
    • FFX with 100-dB SNR and dynamic range
    • Scalable FFX modulation index
    • Selectable 32- to 192-kHz input sample rates
    • I²C control with selectable device address
    • Digital gain/attenuation +48 dB to -80 dB with 0.5-dB/step resolution
    • Soft volume update with programmable ratio
    • Individual channel and master gain/attenuation
    • Dynamic range compression (DRC) or anticlipping mode
    • Audio presets:
      • 15 preset crossover filters
      • 5 preset anticlipping modes
      • Preset night-time listening mode
    • Individual channel soft/hard mute
    • Independent channel volume and DSP bypass
    • I²S input data interface
    • Input and output channel mapping
    • Automatic invalid input-detect mute
    • Up to 5 user-programmable biquads/channel
    • Three coefficients banks for EQ presets storing with fast recall via I²C interface
    • Bass/treble tones and de-emphasis control
    • Selectable high-pass filter for DC blocking
    • Advanced AM interference frequency switching and noise suppression modes
    • Sub channel mix into left and right channels
    • Selectable high- or low-bandwidth noise-shaping topologies
    • Selectable clock input ratio
    • 96 kHz internal processing sample rate
    • Thermal overload and short-circuit protection technology
    • Video apps: 576 x fSinput mode supported
    • Pin and SW compatible with STA335BW, STA339BW, STA339BWS, STA559BW and STA559BWS

Circuit Diagram

EDA Symbols, Footprints and 3D Models

STMicroelectronics - STA333BW

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Quality and Reliability

Part Number Marketing Status Package Grade RoHS Compliance Grade Material Declaration**
PowerSSO 36 Industrial Ecopack2



PowerSSO 36

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PowerSSO 36



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(**) The Material Declaration forms available on may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.

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