Features: `Low Cost, Pin- and Register-Compatible Alternative to D1848
`Single-Chip Integrated Digital Audio Stereo Codec
`Supports the Microsoft Windows Sound System*
`Multiple Channels of Stereo Input and Output
`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
`68-Lead PLCC Package
`Operation from +5 V Supply
`Byte-Wide Parallel Interface to ISA and EISA Buses
`Supports One or Two DMA Channels and Programmed I/OPinout
Specifications Min Max Units
Power Supplies
Digital (VDD) 0.3 6.0 V
Analog (VCC) 0.3 6.0 V
Input Current
(Except Supply Pins) ±10.0 mA
Analog Input Voltage (Signal Pins) 0.3 (VCC) + 0.3 V
Digital Input Voltage (Signal Pins) 0.3 (VDD) + 0.3 V
Ambient Temperature (Operating) 0 +70 °C
Storage Temperature 65 +150 °C
*Stresses greater than those listed under "Absolute Maximum Ratings" may cause ermanent damage to the device. This is a stress rating only and functional peration of the device at these or any other conditions above those indicated in the perational section of this specification is not implied. Exposure to absolute aximum rating conditions for extended periods may affect device reliability.DescriptionThe Parallel-Port AD1846 SoundPort® Stereo Codec integrates ey audio data conversion and control functions into a single integrated ircuit. The AD1846 is intended to provide a complete, ingle-chip audio solution for business audio and multimedia pplications requiring operation from a single +5 V supply.
It provides a direct, byte-wide interface to both ISA ("AT") and ISA computer buses for simplified implementation on a computer otherboard or add-in card. The AD1846 generates enable d direction controls for IC buffers such as the 74_245.
The AD1846 SoundPort Stereo Codec supports a DMA request/grant architecture for transferring data with the host computer us. One or two DMA channels can be supported. rogrammed I/O (PIO) mode is also supported for control register ccesses and for applications lacking DMA control. Two nput control lines support mixed direct and indirect addressing f twenty-one internal control registers over this asynchronous nterface.
External circuit requirements are limited to a minimal number f low cost support components. Anti-imaging DAC output ilters are incorporated on-chip. DAC dynamic range exceeds 0 dB over the 20 kHz audio band. Sample rates from 5.5 kHz o 48 kHz are supported from external crystals.
The Codec includes a stereo pair of analog-to-digital converters nd a stereo pair of digital-to-analog converters. Inputs o the ADC can be selected from four stereo pairs of analog ignals: line, microphone ("mic"), auxiliary ("aux") line #1, and ost-mixed DAC output. A software-controlled programmable ain stage allows independent gain for each channel going into he ADC. The ADCs' output can be digitally mixed with the ACs' input.
The pair of 16-bit outputs from the ADCs is available over a yte-wide bidirectional interface that also supports 16-bit digital nput to the DACs and control information. The AD1846 can ccept and generate 16-bit twos-complement PCM linear digital ata, 8-bit unsigned magnitude PCM linear data, and 8-bit -law or A-law companded digital data.
The DACs are preceded by a digital interpolation filter. An ttenuator provides independent user volume control over each AC channel. Nyquist images and shaped quantization noise re removed from the DACs' analog stereo output by on-chip witched-capacitor and continuous-time filters. Two stereo pairs f auxiliary line-level inputs can also be mixed in the analog domain ith the DAC output.
AD1846 Data Sheet
