TLC32040C Datasheet, PDF (2/33 Pages) Texas Instruments – ANALOG INTERFACE CIRCUITS

TLC32040C, TLC32040I, TLC32041C, TLC32041I
ANALOG INTERFACE CIRCUITS
SLAS014E – SEPTEMBER 1987 – REVISED MAY 1995
description (continued)
The device offers numerous combinations of master clock input frequencies and conversion/sampling rates,
which can be changed via digital processor control.
Typical applications for this integrated circuit include modems (7.2-, 8-, 9.6-, 14.4-, and 19.2-kHz sampling rate),
analog interface for digital signal processors (DSPs), speech recognition/storage systems, industrial process
control, biomedical instrumentation, acoustical signal processing, spectral analysis, data acquisition, and
instrumentation recorders. Four serial modes, which allow direct interface to the TMS32011, TMS320C17,
TMS32020, and TMS320C25 digital signal processors, are provided. Also, when the transmit and receive
sections of the analog interface circuit (AIC) are operating synchronously, it can interface to two SN74299
serial-to-parallel shift registers. These serial-to-parallel shift registers can then interface in parallel to the
TMS32010, TMS320C15, 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 this integrated circuit can
be selected and adjusted coincidentally with signal processing via software control.
The antialiasing input filter comprises seventh-order and fourth-order CC-type (Chebyshev/elliptic transitional)
low-pass and high-pass filters, respectively and a fourth-order equalizer. 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 no filtering is desired, the entire composite 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 converters each have 14 bits of resolution. The A/D and D/A architectures ensure no missing
codes and monotonic operation. An internal voltage reference is provided on the TLC32040 to ease the design
task and to provide complete control over the performance of this integrated circuit. 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 a seventh-order CC-type (Chebyshev/elliptic transitional low-pass filter
followed by a fourth-order equalizer) 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 TLC32040C and TLC32041C are characterized for operation from 0°C to 70°C, and the TLC32040I and
TLC32041I are characterized for operation from – 40°C to 85°C.
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