TDA1546T Datasheet, PDF (6/40 Pages) NXP Semiconductors – Bitstream Continuous Calibration DAC with digital sound processing BCC-DAC

Philips Semiconductors
Bitstream Continuous Calibration DAC with
digital sound processing (BCC-DAC)
Preliminary specification
TDA1546T
4 GENERAL DESCRIPTION
The TDA1546T is the first Bitstream Continuous
Calibration digital-to-analog converter (BCC-DAC) to
feature unique signal processing functions. In addition to
the basic functions of digital filtering and digital-to-analog
conversion, it offers such advanced digital signal
processing functions as volume control, tone control, bass
boost, peak or spectrum analyzer readout and many more
convenient functions. The digital processing features are
of high sound quality due to the wide dynamic range of the
bitstream conversion technique.
The TDA1546T accepts I²S-bus data input formats with
word lengths of up to 20 bits and various Japanese serial
data input formats with word lengths of 16, 18 and 20 bits.
The circuit can operate as a master or slave with different
system clocks (256f_s or 384f_s) and is therefore, eminently
suitable for use in various applications such as DCC, CD,
DAT and MD.
The range of applications is further extended by an
incorporated Digital Speaker System mode (DSS) with
digital crossover filter.
Four cascaded FIR filters and a sample-and-hold function
increase the oversampling rate from 1f_s to 96f_s
(384f_s system clock) or 128f_s (256f_s system clock).
A second-order noise shaper converts this oversampled
data to a bitstream for the 5-bit DACs.
The DACs are of the continuous calibration type and
incorporate a special data coding technique, which
contributes to a high signal-to-noise ratio and dynamic
range.
On-board amplifiers convert the output current to a voltage
signal capable of driving a line output. Externally
connected capacitors perform the required first-order
filtering. Additional post filtering is not required.
Fig.1 Digital audio reconstruction system using the TDA1546T.
January 1995
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