DSD1793_08 Datasheet, PDF (43/50 Pages) Texas Instruments – 24 BIT 192 KHZ SAMPLING ADVANCED SEGMENT AUDIO STEREO DIGITAL TO ANALOG CONVERTER

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DSD1793
SLES075B − MARCH 2003 − REVISED NOVEMBER 2006
THEORY OF OPERATION
Digital
Input
24 Bits
8 fS
Upper
6 Bits
ICOB
Decoder
0–62
Level
MSB
and
Lower 18 Bits
3rd-Order
5-Level
Sigma-Delta
0–4
Level
0–66
Advanced
DWA
Current
Segment
DAC
Figure 48. Advanced Segment DAC With I/V Converter
I/V
Converter
Analog
Voltage
Output
The DSD1793 uses TI’s advanced segment DAC architecture to achieve excellent dynamic performance and
improved tolerance to clock jitter. The DSD1793 provides balanced voltage outputs.
Digital input data via the digital filter is separated into 6 upper bits and 18 lower bits. The 6 upper bits are converted
to inverted complementary offset binary (ICOB) code. The lower 18 bits, in association with the MSB, are processed
by a five-level third-order delta-sigma modulator operated at 64 f_S by default. The 1 level of the modulator is equivalent
to the 1 LSB of the ICOB code converter. The data groups processed in the ICOB converter and third-order
delta-sigma modulator are summed together to an up to 66-level digital code, and then processed by data-weighted
averaging (DWA) to reduce the noise produced by element mismatch. The data of up to 66 levels from the DWA is
converted to an analog output in the differential-current segment section.
This architecture has overcome the various drawbacks of conventional multibit processing and also achieves
excellent dynamic performance.
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