AD1849K

The Serial-Port AD1849K SoundPort® Stereo Codec integrates the key audio data conversion and control functions into a single integrated circuit. The AD1849K is intended to provide a complete, single-chip audio solution for multimedia applications requiring operation from a single +5 V supply.

External signal path circuit requirements are limited to three low tolerance capacitors for line level applications; anti-imaging filters are incorporated on-chip. The AD1849K includes on-chip monauralspeaker and stereo headphone drive circuits that require no additional external components. Dynamic range exceeds 80 dB over the 20 kHz audio band. Sample rates from 5.5 kHz to 48 kHz are supported from external crystals, from an external clock, or from the serial interface bit clock.

The Codec includes a stereo pair of SD analog-to-digital converters and a stereo pair of SD digital-to-analog converters. Analog signals can be input at line levels or microphone levels. 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 left and right channel 16-bit outputs from the ADCs are available over a single bidirectional serial interface that also supports 16-bit digital input to the DACs and control information.

The AD1849K can accept and generate 8-bit m-law or A-law companded digital data. The SD DACs are preceded by a digital interpolation filter. An attenuator provides independent user volume control over each DAC channel. Nyquist images and shaped quantization noise are removed from the DACs' analog stereo output by on-chip switched-capacitor and continuous-time filters. Two independent stereo pairs of line-level (or one line-level and one headphone) outputs are generated, as well as drive for a monaural (mono) speaker.