The TAS5708 is a 20-W, efficient, digital audio power amplifier for driving stereo bridge-tied speakers. A 32-bit datapath eliminates the need for pre-scaling before processing and preserves signal integrity without sacrificing dynamic range. A digital audio processor with fully programmable digital filters allows designers to custom tune speakers for optimum sound in small enclosures. A programmable DRC can adjust power levels for a scaleable design while also enabling night-mode listening modes.

The closed-loop architecture allows the device to operate from poorly regulated supplies. Figure 1 below shows the benefit of the feedback architecture when a noisy supply (1kHz, 500mVpp ripple) modulates a 10kHz audio input. The figure shows a 40dB improvement in sideband suppression when compared to an open-loop design. This correlates directly to a 24dB improvement in distortion as seen in Figure 2.

• Audio Input/Output
  • 20-W Into an 8-Ω Load From an 18-V Supply
  • Wide PVCC Range (10 V to 26 V); 3.3 V Digital Supply
  • Supports One Serial Audio Input (8 kHz - 48 kHz Sample Rates) (LJ/RJ/I2S)
  • Power-Stage Feedback Allows Operation From Poorly Regulated Power Supplies
• Audio/PWM Processing
  • Factory-Trimmed Internal Oscillator for Automatic Rate Detection
  • High-End 32-Bit Data Path Audio Processor
  • 14 Biquads for Speaker EQ
  • Dynamic Range Control (DRC)
• Benefits
  • EQ: Speaker Equalization Improves Audio Performance
  • DRC: Enables Speaker Protection and Night-Mode Listening.
  • Autobank Switching: Preloaded Coefficients for Three Different Sample Rates Eliminates the Need to Update Coefficients When Sample Rate Changes
  • Autodetect: Automatically Detects Sample-Rate Changes Eliminating the Need for External Microprocessor Intervention
  • Closed-Loop Power Stage: Enables Wide PVCC Operating Range and Reduced Power Supply Ripple Distortion