EVAL-ADAU1401EBZ View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'EVAL-ADAU1401EBZ' PDF : 52 Pages View PDF
ADAU1401A
AUDIO DACs
The ADAU1401A includes four Σ-Δ DACs. The SNR of the
DACs is 104 dB, and the THD + N is −90 dB. A full-scale
output on the DACs is 0.9 V rms (2.5 V p-p).
The DACs are in an inverting configuration. If a signal inversion
from input to output is undesirable, it can be reversed either by
using an inverting configuration for the output filter or by simply
inverting the signal in the SigmaDSP program flow.
The DAC outputs can be filtered with either an active or passive
reconstruction filter. A single-pole, passive, low-pass filter with
a 50 kHz corner frequency, as shown in Figure 18, is sufficient
to filter the DAC out-of-band noise, although an active filter may
provide better audio performance. Figure 19 shows a triple-pole,
active, low-pass filter that provides a steeper roll-off and better
stop-band attenuation than the passive filter. In this configuration,
the V+ and V− pins of the AD8606 op amp are set to VDD and
ground, respectively.
To properly initialize the DACs, the DS[1:0] bits in the DAC
setup register (Address 2087) should be set to 01.
DAC_OUT
47µF 560Ω
FILTER_OUT
5.6nF
Figure 18. Passive DAC Output Filter
DAC_OUT
4.75kΩ 4.75kΩ
150pF
C8
470µF
AD8608
47µF 604Ω
3.3nF
49.9kΩ
FILTER_OUT
Figure 19. Active DAC Output Filter
Rev. A | Page 21 of 52
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