The STA369BWS is an integrated solution of digital audio processing, digital amplifier controls and power output stage 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 STA369BWS 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.
One other option is to configure the IC as having one channel output that can be provided by parallel BTL to obtain 1 x 40 W of output power. In this configuration the CONFIG pin must be connected to VDD.
Also provided in the STA369BWS 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 to manage low-frequency quantization noise in filters with very low cut-off frequencies. The coefficient range -4 to +4 allows easy high-shelf filter usage and better sound shaping. 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. Dual-band DRC dynamically equalizes the system to provide linear frequency speaker response regardless of output power level. This feature separates the audio frequency band into two sub-bands independently processed to provide better sound clarity and to avoid speaker saturation.
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.
The new F3X™ modulation is capable of digitally filtering the PWM carrier to simplify external filtering requirements, AM interference and EMI. F3X™ is implemented in the auxiliary output of STA369BWS and it is specifically designed for application where a simple op-amp can be used to drive an auxiliary headphone line.
- 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 (up to 100%)
- Selectable 32- to 192-kHz input sample rates
- I2 C control with selectable device address
- Digital gain/attenuation +48 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 (B2 DRC) or as independent limiters/compressors with optional global DRC capability
- 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 night-time listening mode
- Individual channel soft/hard mute
- Independent channel volume and DSP bypass
- I2 S input data interface
- Input and output channel mapping
- Automatic invalid input-detect mute
- Up to 8 user-programmable biquads/channel
- Three coefficients banks for EQ presets storing with fast recall via I2 C interface
- Extended filter dynamics +4/-4 for better sound shaping and easier filter implementation
- Bass/treble tones and de-emphasis control
- Selectable high-pass filter for DC blocking
- Advanced AM interference frequency switching and noise suppression modes
- F3X™ advanced PWM modulation scheme for carrier suppression (headphone or line output)
- 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 cut-off frequency filters
- Thermal overload and short-circuit protection embedded
- Video apps: 576 x fS input mode supported
- PCB manufacturing short-circuit protection technology