AD1847

a FEATURES Single-Chip Integrated ⌺⌬ Digital Audio Stereo Codec Supports the Microsoft Windows Sound System* Multiple Channels of Stereo Input Analog and Digital Signal Mixing Programmable Gain and Attenuation On-Chip Signal Filters Digital Interpolation and Decimation Analog Output Low-Pass Sample Rates from 5.5 kHz to 48 kHz 44-Lead PLCC and TQFP Packages Operation from +5 V Supplies Serial Digital Interface Compatible with ADSP-21xx Fixed-Point DSP I S A B U S Serial-Port 16-Bit SoundPort Stereo Codec AD1847 ASIC AD1847 DSP Figure 1. Example System Diagram External circuit requirements are limited to a minimal number of low cost support components. Anti-imaging DAC output filters are incorporated on-chip. Dynamic range exceeds 70 dB over the 20 kHz audio band. Sample rates from 5.5 kHz to 48 kHz are supported from external crystals. The Codec includes a stereo pair of ∑∆ analog-to-digital converters (ADCs) and a stereo pair of ∑∆ digital-to-analog converters (DACs). Inputs to the ADC can be selected from four stereo pairs of analog signals: line 1, line 2, auxiliary (“aux”) line #1, and post-mixed DAC output. A software-controlled programmable gain stage allows independent gain for each channel going into the ADC. The ADCs’ output can be digitally mixed with the DACs’ input. The pair of 16-bit outputs from the ADCs is available over a serial interface that also supports 16-bit digital input to the DACs and control/status information. The AD1847 can accept and generate 1...