TLC32044C Datasheet, PDF (2/39 Pages) Texas Instruments – VOICE-BAND ANALOG INTERFACE CIRCUITS

TLC32044C, TLC32044E, TLC32044I, TLC32044M, TLC32045C, TLC32045I
VOICE-BAND ANALOG INTERFACE CIRCUITS
SLAS017F – MARCH 1988 – REVISED MAY 1995
TA
0°C to 70°C
– 20°C to 85°C
– 40°C to 85°C
– 55°C to 125°C
AVAILABLE OPTIONS
PACKAGE
PLASTIC CHIP
CARRIER
(FN)
PLASTIC DIP
(N)
CERAMIC DIP
(J)
TLC32044CFN
TLC32044CN
TLC32045CFN
TLC32045CN
TLC32044EFN
TLC32044IN
TLC32045IN
TLC32044MJ
CHIP CARRIER
(FK)
TLC32044MFK
description (continued)
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.
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