TI’s TAS5727 is a 25W digital audio power amplifier used to drive stereo bridge speakers. The VDD voltage ranges from 8V to 26V. It can provide 25W power to 8 ohm loads at 20V power supply. It also supports 4 ohm loads in BTL configuration and supports 44.1- kHz to 48-kHz sampling frequency, mainly used in LCD TVs, LED TVs and sound bars. This article introduces the TAS5727 main features, functional block diagram, simplified application circuit, evaluation modules TAS5727EVM and MC57xxPSIA main features, circuit diagrams and the evaluation module TAS5727EVM bill of materials (BOM).
25-W DIGITAL AUDIO POWER AMPLIFIER WITH EQ AND DRC
The TAS5727 is a 25-W, efficient, digital-audio power amplifier for driving stereo bridge-tied speakers. One serial data input allows processing of up to two discrete audio channels and seamless integration to most digital audio processors and MPEG decoders. The device A fully programmable data path accepts a wide range of input data and data rates. A fully programmable data path routes these channels to the internal speaker drivers.
The TAS5727 is a slave-only device receiving all clocks from external sources. The TAS5727 operates with a PWM carrier between a 384-kHz switching rate and a 288-KHz switching rate, depending on the input sample rate. Oversampling combined with a fourth- order noise shaper provides a flat noise floor and excellent dynamic range from 20 Hz to 20 kHz.
Main features of TAS5727:
Audio Input/Output
25 W Into an 8-Ω Load From a 20-V Supply
Wide PVDD Range, From 8 V to 26 V
Supports BTL Configuration With 4-Ω Load
Efficient Class-D Operation Eliminates Need for Heatsinks
One Serial Audio Input (Two Audio Channels)
I2C Address Selection Pin (Chip Select)
Single Output Filter PBTL Support
Supports 44.1-kHz to 48-kHz Sample Rate (LJ/RJ/I2S)
Audio/PWM Processing
Independent Channel Volume Controls With Gain of 24 dB to
Mute With 0.125-dB Resolution Steps
Programmable Two-Band Dynamic-Range Control
18 Programmable Biquads for Speaker EQ and Other
Audio-Processing Features
Programmable Coefficients for DRC Filters
DC Blocking Filters
General Features
I2C Serial Control Interface
Operational Without MCLK
Requires Only 3.3 V and PVDD
No External Oscillator: Internal Oscillator for Automatic
Rate Detection
Surface-Mount, 48-Pin HTQFP Package
TAS5727 application:
LCD TV, LED TV, Soundbar
figure 1. TAS5727 functional block diagram
figure 2. TAS5727 Power Stage Functional Block
image 3. TAS5727 Simplified Application Block Diagram
TAS5727 25W Digital Digital Amplifier TAS5727EVM
TAS5727 25W Digital Input Amplifier with EQ and 2-Band DRC
The TAS5727EVM evaluation module demonstrates the TAS5727 device from Texas Instruments. The TAS5727 combines a high-performance PWM processor with a class-D audio power amplifier. This EVM can be configured with two bridge-tied loads (BTL) (2.0). The Pulse Width Modulator (PWM) is based on TI’s Equibit™ technology. The TAS5727 has additional audio processing features like 3D, Bass Boost and 2-band DRC.
The EVM software, with its graphic user interface (GUI), facilitates evaluation by providing access to the TAS5727EVM registers through a USB port.
TAS5727EVM and MC57xxPSIA key features:
• Channel evaluation module design
• Self-contained protection systems and control pins
• USB interface
• Standard I2S data input using optical or coaxial inputs
• Analog input through analog-to-digital converter
• Subwoofer connection—the PWM terminal provides the PWM signal and power to an external subwoofer board
• Double-sided, plated-through PCB, 1oz copper, 2mm
• Access to control signal gain and data format through EVM-software GUI
Figure 4. TAS5727EVM Evaluation Module Outline Drawing
Figure 5. TAS5727EVM Signal Path and Complete System Block Diagram
Image 6. TAS5727EVM and MC57xxPSIA General Connection Diagram
Figure 7. TAS5727EVM circuit diagram
Figure 8. MC57xxPSIA circuit diagram (1)
Figure 9. MC57xxPSIA circuit diagram (2)
Figure 10. MC57xxPSIA circuit diagram (3)
TAS5727EVM Bill of Materials (BOM):
For details, see:
http://focus.ti.com/lit/ds/symlink/tas5727.pdf
and
http://focus.ti.com/lit/ug/slou299/slou299.pdf
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