SLAS017F - MARCH 1988 - REVISED MAY 1995
The TLC32044 and TLC32045 are complete analog-to-digital and digital-to-analog input and output systems on single monolithic CMOS chips. The TLC32044 and TLC32045 integrate a bandpass switched-capacitor antialiasing input filter, a 14-bit-resolution A/D converter, four microprocessor-compatible serial port modes, a 14-bit-resolution D/A converter, and a low-pass switched-capacitor output-reconstruction filter. The devices offer numerous combinations of master clock input frequencies and conversion/sampling rates, which can be changed via digital processor control.
Typical applications for the TLC32044 and TLC32045 include speech encryption for digital transmission, speech recognition/ storage systems, speech synthesis, modems (7.2-, 8-, 9.6-, 14.4-, and 19.2-kHz sampling rate), analog interface for digital signal processors (DSPs), industrial process control, biomedical instrumentation, acoustical signal processing, spectral analysis, data acquisition, and instrumentation recorders. Four serial modes, which allow direct interface to the TMS(SMJ)320C17, TMS(SMJ)32020, TMS(SMJ)320C25, and TMS(SMJ)320C30 digital signal processors, are provided. Also, when the transmit and receive sections of the analog interface circuit (AIC) are operating synchronously, it will interface to two SN74(54)299 serial-to-parallel shift registers. These serial-to-parallel shift registers can then interface in parallel to the TMS(SMJ)32010, TMS(SMJ)320C15, and other digital signal processors, or external FIFO circuitry. Output data pulses are emitted to inform the processor that data transmission is complete or to allow the DSP to differentiate between two transmitted bytes. A flexible control scheme is provided so that the functions of the TLC32044 or TLC32045 can be selected and adjusted coincidentally with signal processing via software control.
The antialiasing input filter comprises eighth-order and fourth-order CC-type (Chebyshev/elliptic transitional) low-pass and high-pass filters, respectively. The input filter is implemented in switched-capacitor technology and is preceded by a continuous time filter to eliminate any possibility of aliasing caused by sampled data filtering. When only low-pass filtering is desired, the high-pass filter can be switched out of the signal path. A selectable, auxiliary, differential analog input is provided for applications where more than one analog input is required.
The A/D and D/A architectures ensure no missing codes and monotonic operation. An internal voltage reference is provided to ease the design task and to provide complete control over the performance of the TLC32044 or TLC32045. The internal voltage reference is brought out to a terminal and is available to the designer. Separate analog and digital voltage supplies and grounds are provided to minimize noise and ensure a wide dynamic range. Also, the analog circuit path contains only differential circuitry to keep noise to an absolute minimum. The only exception is the DAC sample and hold, which utilizes pseudo-differential circuitry.
The output-reconstruction filter is an eighth-order CC-type (Chebyshev/elliptic transitional low-pass filter) followed by a second-order (sin x)/x correction filter and is implemented in switched-capacitor technology. This filter is followed by a continuous-time filter to eliminate images of the digitally encoded signal. The on-board (sin x)/x correction filter can be switched out of the signal path using digital signal processor control, if desired.
The TLC32044C and TLC32045C are characterized for operation from 0°C to 70°C. The TLC32044E is characterized for operation from -20°C to 85°C. The TLC32044I and TLC32045I are characterized for operation from -40°C to 85°C. The TLC32044M is characterized for operation from -55°C to 125°C.
View more information about generic part numbers:TLC32044, TLC32045
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