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.