Описание
The TLC320AC01 analog interface circuit (AIC) is an audio-band processor that provides an analog-to-digital and digital-to-analog input/output interface system on a single monolithic CMOS chip. This device integrates a band-pass switched-capacitor antialiasing input filter, a 14-bit-resolution analog-to-digital converter (ADC), a 14-bit-resolution digital-to-analog converter (DAC), a low-pass switched-capacitor output-reconstruction filter, (sin x)/x compensation, and a serial port for data and control transfers. The internal circuit configuration and performance parameters are determined by reading control information into the eight available data registers. The register data sets up the device for a given mode of operation and application. The major functions of the TLC320AC01 are: 1. To convert audio-signal data to digital format by the ADC channel 2. To provide the interface and control logic to transfer data between its serial input and output terminals and a digital signal processor (DSP) or microprocessor 3. To convert received digital data back to an audio signal through the DAC channel The antialiasing input low-pass filter is a switched-capacitor filter with a sixth-order elliptic characteristic. The high-pass filter is a single-pole filter to preserve low-frequency response as the low-pass filter cutoff is adjusted. There is a three-pole continuous-time filter that precedes this filter to eliminate any aliasing caused by the filter clock signal. The output-reconstruction switched-capacitor filter is a sixth-order elliptic transitional low-pass filter followed by a second-order (sin x)/x correction filter. This filter is followed by a three-pole continuous-time filter to eliminate images of the filter clock signal. The TLC320AC01 consists of two signal-processing channels, an ADC channel and a DAC channel, and the associated digital control. The two channels operate synchronously; data reception at the DAC channel and data transmission from the ADC channel occur during the same time interval. The data transfer is in2s-complement format. There are three basic modes of operation available: the stand-alone analog-interface mode, the master-slave mode, and the linear-codec mode. In the stand-alone mode, the TLC320AC01 generates the shift clock and frame synchronization for the data transfers and is the only AIC used. The master-slave mode has one TLC320AC01 as the master that generates the master-shift clock and frame synchronization; the remaining AICs are slaves to these signals. In the linear-codec mode, the shift clock and the frame-synchronization signals are externally generated and the timing can be any of the standard codec-timing patterns. Typical applications for this device include modems, speech processing, analog interface for DSPs, industrial-process control, acoustical-signal processing, spectral analysis, data acquisition, and instrumentation recorders. The TLC320AC01C is characterized for operation from 0°C to 70°C.
