PCM1741/E2K BURR-BROWN [Burr-Brown Corporation], PCM1741/E2K Datasheet - Page 20

• Manufacturer Part Number: PCM1741/E2K
• Description: +3.3V Single-Supply, 24-Bit, 96kHz Sampling Enhanced Multilevel, Delta-Sigma, Audio DIGITAL-TO-ANALOG CONVERTER
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

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data is transmitted via a coaxial cable to the digital audio
receiver on the DEM-DAI1741 demo board. The receiver is
then configured to output 24-bit data in either I
justified data format. The DAC audio interface format is
programmed to match the receiver output format. The ana-
log output is then taken from the DAC post filter and
connected to the analog analyzer input of the measurement
system. The analog input is band limited using filters resi-
dent in the analyzer. The resulting THD+N is measured by
the analyzer and displayed by the measurement system.
DYNAMIC RANGE
Dynamic range is specified as A-Weighted, THD+N mea-
sured with a –60dBFS, 1kHz digital sine wave stimulus at
the input of the DAC. This measurement is designed to give
a good indicator of how the DAC will perform given a low-
level input signal.
FIGURE 18. Test Setup for Dynamic Range and SNR Measurements.
NOTES: (1) Infinite Zero Detect Mute disabled.
(2) Results without A-Weighting will be approxi-
mately 3dB worse.
S/PDIF
Output
(Dynamic Range)
Dither Off (SNR)
1kHz Sine Wave
0% Full-Scale,
–60dBFS,
Generator
Digital
rms Mode
Analyzer
Display
and
2
S or left-
Evaluation Board
DEM-DAI1741
Receiver
S/PDIF
A-Weight
Filter
(1)
The measurement setup for the dynamic range measurement
is shown in Figure 18, and is similar to the THD+N test
setup discussed previously. The differences include the band
limit filter selection, the additional A-Weighting filter, and
the –60dBFS input level.
IDLE CHANNEL SIGNAL-TO-NOISE RATIO
The SNR test provides a measure of the noise floor of the
DAC. The input to the DAC is all “0”s data, and the DAC’s
Infinite Zero Detect Mute function must be disabled (default
condition at power up for the PCM1741). This ensures that
the delta-sigma modulator output is connected to the output
amplifier circuit so that idle tones (if present) can be ob-
served and effect the SNR measurement. The dither function
of the digital generator must also be disabled to ensure an all
“0”s data stream at the input of the DAC. The measurement
setup for SNR is identical to that used for dynamic range,
with the exception of the input signal level (see the notes
provided in Figure 18).
Option = A-Weighting
HPF = 22Hz
LPF = 22kHz
PCM1741
Band Limit
(1)
(2)
f
–3dB
Notch Filter
2nd-Order
Low-Pass
f
C
Filter
= 1kHz
= 54kHz
PCM1741
SBAS175