ST公司的TS4657是集成高性能音频线路驱动器的立体声DAC,能从3.0V-5.5V单电源中产生2.2Vrms的输出.取样频率32-48kHz,16-24位音频数据格式,SNR为95dB,主要应用在数字机顶盒,DVD播放器,DTV,笔记本电脑,手提音频设备和声卡.本文介绍了TS4657主要特性,方框图,典型应用电路和测试电路.

The TS4657 is a stereo DAC that integrates a high-performance audio line driver capable of generating a 2.2 Vrms output level from a single 3.0 to 5.5 V supply. One single supply is sufficient for the digital and analog parts of the circuit, thus eliminating the need for external regulators.

The TS4657 is a low-power consumption device. It features only 22 mW power dissipation at a 3.0 V power supply in full operation. A 16-bit multi-bit sigma delta DAC is used,operating at 256xFs with oversampling digital interpolation filters. The digital audio data can be 16-to 24-bit long and sample rates from 32 to 48 kHz are supported.

The output stage signal is ground-referenced by using an internal self-generated negative power supply, and as such external bulky output coupling capacitors are not necessary.

The TS4657 is packaged in a small 4 x 4 mm QFN20 package, ideal for portable applications.

TS4657主要特性:

■ Single 3.0 to 5.5 V supply for DAC and line driver

■ Audio line output: 2.2 Vrms for all VCC range

■ 16- to 24-bit audio data format stereo DAC, 32 to 48 kHz sample rate

■ I²S, right- or left-justified compatible digital audio interface

■ 95 dB SNR A-weighted at 48 kHz, VCC =5 V

■ 7.4 mA current consumption at VCC = 3.0 V, full operation

■ Internal negative power supply to ensure ground-referenced, capless outputs

■ No external capacitor needed for the negative power supply generation

■ Integrated structure to suppress pop and click noise

■ Available in thin QFN20 4 mm x 4 mm package

TS4657应用:

■ Digital set-top boxes

■ DVD players

■ Digital TVs

■ Notebooks

■ Portable audio equipment

■ Sound cards

图1.TS4657方框图

图2.TS4657典型应用电路

图3.TS4657典型测试电路图