TLC32047C

The TLC32047C wide-band analog interface circuit (AIC) is a complete analog-to-digital and digital-to-analog interface system for advanced digital signal processors (DSPs) similar to the TMS32020, TMS320C25, and TMS320C30. The TLC32047 offers a powerful combination of options under DSP control: three operating modes [dual-word (telephone interface), word, and byte] combined with two word formats (8 bits and 16 bits) and synchronous or asynchronous operation. TLC32047C provides a high level of flexibility in that conversion and sampling rates, filter bandwidths, input circuitry, receive and transmit gains, and multiplexed analog inputs are under processor control.
This AIC TLC32047C features a
• band-pass switched-capacitor antialiasing input filter
• 14-bit-resolution A/D converter
• 14-bit-resolution D/A converter
• low-pass switched-capacitor output-reconstruction filter
The antialiasing input filter of TLC32047C comprises eighth-order and fourth-order CC-type (Chebyshev/elliptic transitional) low-pass and high-pass filters, respectively. The input filter is implemented in switchedcapacitor technology and is preceded by a continuous time filter to eliminate any possibility of aliasing caused by sampled data filtering. When low-pass filtering is desired, the high-pass filter can be switched out of the signal path. A selectable auxiliary differential analog input of TLC32047C is provided for applications where more than one analog input is required.

The output-reconstruction filter of TLC32047C 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 sample data signal. The on-board (sin x)/x correction filter can be switched out of the signal path using digital signal processor control. 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 IC. The internal voltage reference of TLC32047C is brought out to REF. Separate analog and digital voltage supplies and ground are provided to minimize noise and ensure a wide dynamic range. The analog circuit path of TLC32047C contains only differential circuitry to keep noise to a minimum. The exception is the DAC sample-and-hold, which utilizes pseudo-differential circuitry.

The TLC32047C is characterized for operation from 0°C to 70°C, and the TLC32047I is characterized for operation from 40°C to 85°C.